AskNat – Your GCSE Science Questions Answered by Students

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List of popular questions asked in GCSE Sciences

• A 45-year-old man exercised on a rowing machine for six minutes. A fitness monitor recorded his heart rate and breathing rate every minute. The graph below shows the results Explain the ways the man’s body has responded to the exercise. Use information from the graph above. – 7039
• A book rests on a table. Draw a free body force diagram to show the forces acting on the book. Use arrows to represent the forces. – 7513
• A boy picks up a hot plate and quickly drops it. This is a reflex action. Describe the sequence of events that happens in his nervous system during this reflex action. – 7616
• A car takes 6 m to brake when moving at 8 m/s. Look at the graph of a car travelling at 8 m/s, starting to brake and then stopping. Calculate the acceleration of the car during braking. Show your working and state the unit. – 7512
• A cube-shaped nanoparticle has sides of length 50 nm. Calculate the surface area to volume ratio for this nanoparticle. Use the equation: ratio = surface area ÷ volume Surface area to volume ratio – 7553
• A defibrillator can transfer a charge to regulate a person’s heartbeat. Figure 2 shows a defibrillator. When the defibrillator is in use, a potential difference of 4800 V is applied across the person’s chest. A charge of 0.16 coulombs passes through the person’s chest in 4.0 ms Calculate the resistance of the person’s chest. – 6033
• A domestic wind turbine has a power rating which varies from 1.0 kW to 3.0 kW. The domestic wind turbine has an electrical resistance of 23 Ω. It generates a current of 11 A on a windy day. Calculate the power output in kW of the turbine on this day. – 7528
• A gardener wants to add compost to the soil to increase his yield of strawberries. The gardener wants to make his own compost. Some of the leaves from the gardener’s strawberry plant die. The dead leaves fall off the strawberry plant onto the ground. The carbon in the dead leaves is recycled through the carbon cycle. Explain how the carbon is recycled into the growth of new leaves. – 7086
• A glucose tolerance test can help identify if a person has diabetes. The graphs show a glucose tolerance test in three people A, B, and C. One person is healthy and the other two people have different types of diabetes. Explain the differences between the three graphs and describe how each person with diabetes could control their blood glucose levels. Use information from the graphs in your answer. – 7611
• A group of students investigate the effect of temperature on the breakdown of the fat in milk by the enzyme lipase. In their investigation they use an indicator called phenolphthalein. Phenolphthalein is pink in alkali conditions but becomes colourless when the pH falls below pH 8. A student puts 5 drops of phenolphthalein and 5 ml of full fat milk in to a test tube. She adds 1 ml of lipase, stirs the mixture and times how long it takes to lose the pink colour. Other students repeat this but at different temperatures. Plot a graph of the results and draw a line of best fit. – 7607
• A large amount of aluminium sulfate was accidentally added to the drinking water supply at a water treatment works. Plan an investigation to find the total mass of dissolved solids in a 100 cm3 sample of the drinking water. Your investigation should produce valid results. – 6177
• A Light Dependent Resistor (LDR) is used to turn on an outside lamp when it gets dark. Part of the circuit is shown in Figure 2.A student investigated how – 6035
• A local council wants to keep a particular section of a road clear of ice in the winter. Describe the advantages and disadvantages of keeping the road clear of ice using: • energy storage • salt • undersoil electrical heating. – 6003
• A mixture contains 1.00 kg of aluminium and 3.00 kg of iron oxide. The equation for the reaction is: 2 Al + Fe2O3 → 2 Fe + Al2O3 Show that aluminium is the limiting reactant. Relative atomic masses (Ar): O = 16 Al = 27 Fe = 56 – 6151
• A mixture contains 1.00 kg of aluminium and 3.00 kg of iron oxide. The equation for the reaction is: Show that aluminium is the limiting reactant. Relative atomic masses – 6102
• A molecule of methane can be represented in several different ways as shown in Figure. These representations have been labelled A–E to assist you in your answer. Describe what information can be obtained from each representation including the limitations of these representations of methane – 9005
• A molecule of methane can be represented in several different ways as shown. These representations have been labelled A–E to assist you in your answer. Describe what information can be obtained from each representation including the limitations of these representations of methane.
• A patient with a leaking heart valve may have the valve replaced. A study compared two different types of replacement heart valve: • mechanical valves • biological valves from pigs. The data used in the study was collected from female patients aged 50–69. The following table shows the data.- 6020
• A pressure of 100 atmospheres is used instead of atmospheric pressure. The higher pressure gives a greater yield of methanol and an increased rate of reaction. Explain why. – 6107
• A radioactive rock is placed near to the front of a Geiger-Müller (GM) tube. A radioactivity count-rate is first made in air. The count-rate is measured again with each of three different absorbers between the rock and the GM tube. A scientist has an idea that the rock emits three different types of radiation. Explain how the data in this table supports the scientist’s idea – 8022
• A radioactive tracer is put into an underground water pipe. A detector above the ground measures the radioactivity. The graph shows the amount of radioactivity detected along the length of the pipe. Describe the patterns in the graph and explain how this information can be useful ?
• A recessive allele causes syndrome H. A heterozygous woman and a homozygous recessive man want to have a child. Draw a Punnett square diagram to determine the probability of the child having syndrome H. Identify any children with syndrome H. Use the following symbols: A = dominant allele a = recessive allele Probability = _______ % – 7074
• A rocket carrying a vehicle called the Mars Rover was sent to Mars. The Mars Rover has a mass of 185 kg.  The gravitational field strength (g) on Mars is 3.75 N/kg. Calculate the weight of the Rover vehicle on Mars. Show your working and give your answer to 3 significant figures. State the unit for weight. answer – 7530
• A rocket carrying a vehicle called the Mars Rover was sent to Mars. The Mars Rover has a mass of 185 kg. The gravitational field strength (g) on Mars is 3.75 N/kg. Calculate the weight of the Rover vehicle on Mars. Show your working and give your answer to 3 significant figures. State the unit for weight. – 7507
• A salt marsh is a large, muddy area of land where a river joins the sea. * In some salt marshes large sand banks have been built. These stop tides from entering the salt marsh. The level of soil on the salt marsh builds up and the marsh turns into dry land. Local farmers want to turn salt marshes into dry land and other people want to leave it as a salt marsh. Explain why. Use ideas about land use and biodiversity in your answer. – 7628
• A sample of magnesium contains 79% of magnesium-24 atoms ,10% of magnesium-25 atoms ,11% of magnesium-26 atoms. In most calculations the relative atomic mass of magnesium used is 24.Use this information to explain why, in this sample, magnesium has a relative atomic mass of 24.3 – 9001
• A sample of water was contaminated with a dissolved solid. Devise a plan to separate pure water from this mixture, including a test to show that the water obtained is neutral. You may use some or all of the apparatus shown in Figure 11 and any other laboratory apparatus – 9014
• A scientist investigated the effect of three different antibiotics on three different types of bacteria, A, B and C. This is the method used. 1. Grow bacteria A on an agar plate. 2. Put three separate paper discs each containing one of the antibiotics (1, 2 and 3) onto the agar plate3. Put the agar plate into an incubator for 48 hours. 4. Repeat steps 1-3 for bacteria B and for bacteria C. Figure 1 shows the scientist’s results – 7024
• A scientist noticed that in one area the gorse plants had yellow leaves and had stunted growth. One reason for yellow leaves and stunted growth is a deficiency of nitrate ions in the soil. Explain two other possible reasons for the yellow leaves and stunted growth. Do not refer to nitrate ions in your answer. – 7030
• A solution of potash alum has a concentration of 258 g/dm3 Calculate the mass of potash alum needed to make 800 cm3 of a solution of potash alum with a concentration of 258 g/dm3 Give your answer to 3 significant figures. – 6175
• A solution of potash alum has a concentration of 258 g/dm3 Calculate the mass of potash alum needed to make 800 cm3 of a solution of potash alum with a concentration of 258 g/dm3 Give your answer to 3 significant figures. -6101
• A spot-welder is a device that uses a transformer to produce a large current to join sheets of metal together. Figure 2 shows a transformer demonstrating how a large current can heat and join two nails together Calculate the current from the power supply needed to provide a power output of 336 W. Use the data in Figure 2. The transformer is 100% efficient. – 6079
• A student cut a piece of onion and placed it on a microscope slide. The student then placed this slide on the stage of a light microscope and looked through the eyepiece. No cells could be seen in the piece of onion. Explain two ways this method could be improved to see details of the onion cells. – 10003
• A student does a titration to find the volume of sulfuric acid that reacts with 25 cm3 of potassium hydroxide solution.The figure below shows the equipment used.Describe how the student would use the equipment in the figure above to complete the titration – 6134
• A student does an experiment using 0.2 kg of water. Here is some information from the experiment. Describe how the student should carry out the experiment, including the equipment used. In your answer calculate the change in internal energy for the water. You may include a diagram in your answer. – 7505
• A student does an experiment using 0.2 kg of water. Here is some information from the experiment: Describe how the student should carry out the experiment, including the equipment used. In your answer calculate the change in internal energy for the water. You may include a diagram in your answer. – 7529
• A student has unlabelled samples of three liquids. The student knows that the three liquids are: • pentane, C5H12 • pentene, C5H10 • ethanoic acid, CH3COOH. Describe tests that the student should do to identify each of the three liquids. Include balanced symbol equations for the reactions described. – 7569
• A student investigated how a change in concentration affects the rate of the reaction between zinc powder and sulfuric acid. The equation for the reaction is: Zn(s) + H2SO4(aq) → ZnSO4 (aq) + H2 (g). – 6014
• A student investigated how the current in a series circuit varied with the resistance of a variable resistor. Figure 1 shows the circuit used. – 6034
• A student investigated how the resistance of a piece of nichrome wire varies with length. Figure 1 shows part of the circuit the student used. Describe how the student would obtain the data needed for the investigation. Your answer should include a risk assessment for one hazard in the investigation.
• A student investigated how the temperature of a lump of ice varied as the ice was heated. The student recorded the temperature until the ice melted and then the water produced boiled. The figure below shows the student’s results. The power output of the heater was constant. – 6036
• A student investigated the colours in three different flowers, A, B and C.  The colours are soluble in ethanol but are insoluble in water. This is the method used. 1. Crush flower A. 2. Add ethanol to flower A. 3. Filter the mixture. 4. Put spots of the coloured filtrate on to the chromatography paper. 5. Repeat steps 1-4 with flowers B and C. Figure 1 shows the apparatus used. The student made two mistakes in setting up the apparatus. Give one problem caused by each mistake.- 6130
• A student investigated the effect of different sugar solutions on potato tissue. This is the method used. 1. Add 30 cm3 of 0.8 mol dm−3 sugar solution to a boiling tube. 2. Repeat step 1 with equal volumes of 0.6, 0.4 and 0.2 mol dm−3 sugar solutions. 3. Use water to give a concentration of 0.0 mol dm−3 . 4. Cut five cylinders of potato of equal size using a cork borer. 5. Weigh each potato cylinder and place one in each tube. 6. Remove the potato cylinders from the solutions after 24 hours. 7. Dry each potato cylinder with a paper towel. 8. Reweigh the potato cylinders. The table below shows the results. – 7012
• A student investigated the effect of temperature on the activity of amylase. The figure below shows the apparatus used. This is the method used. 1. Set up the apparatus as shown in the figure above. 2. After 5 minutes, pour the starch solution into the amylase solution and mix. 3. Remove one drop of the starch-amylase mixture and place onto a spotting tile. 4. Immediately add two drops of iodine solution to the starch-amylase mixture on the spotting tile. 5. Record the colour of the iodine solution added to the starch-amylase mixture. 6. Repeat steps 3 to 5 every minute until the iodine solution stays yellow-brown. 7. Repeat steps 1 to 6 using water at different temperatures.- 7016
• A student investigated the movement of water. Hens’ eggs were placed in vinegar for two days to dissolve the shell. This makes the eggs permeable to water. The eggs were then weighed and placed in different solutions. After 24 hours the eggs were weighed again. Figure 11 shows the results. – 10001
• A student investigated the reaction of copper carbonate with dilute sulfuric acid. The student used the apparatus shown in the figure below Describe a safe method for making pure crystals of copper sulfate from copper carbonate and dilute sulfuric acid. Use the information in the figure above to help you. In your method you should name all of the apparatus you will use. – 6143
• A student investigated the reactions of copper carbonate and copper oxide with dilute hydrochloric acid. In both reactions one of the products is copper chloride. Describe how a sample of copper chloride crystals could be made from copper carbonate and dilute hydrochloric acid. – 6144
• A student investigated the reactions of copper carbonate and copper oxide with dilute hydrochloric acid. In both reactions one of the products is copper chloride. Describe how a sample of copper chloride crystals could be made from copper carbonate and dilute hydrochloric acid. – 6109
• A student investigated the reactions of copper carbonate and copper oxide with dilute hydrochloric acid. In both reactions one of the products is copper chloride. Describe how a sample of copper chloride crystals could be made from copper carbonate and dilute hydrochloric acid. – 6119
• A student investigated the temperature change in displacement reactions between metals and copper sulfate solution. The table below shows the student’s results. The temperature change depends on the reactivity of the metal. The student’s results are used to place copper, iron, magnesium and zinc in order of their reactivity. Describe a method to find the position of an unknown metal in thisreactivity series. Your method should give valid results. – 6152
• A student investigated the temperature change in the reaction between dilute sulfuric acid and potassium hydroxide solution. This is the method used. – 6011
• A student investigated the thermal conductivity of different metals. This is the method used: 1. Measure the mass of an ice cube. 2. Put the ice cube on a metal block which is at room temperature. 3. Measure the mass of the ice cube after one minute. 4. Repeat with other blocks of the same mass made from different metals. – 6047
• A student investigates building model transformers in the laboratory. Look at the diagram. The student builds four different transformers, each with different primary and secondary coils. Using an input voltage of 12 V the student measures the output voltage. Explain how a transformer works and if this data supports the expected output voltages. – 7519
• A student investigates if lamps are brighter in a series circuit or a parallel circuit. He sets up two different circuits, A and B. State which circuit will have the brightest lamps and explain why. In your answer, include the variables that the student will need to control in this experiment. – 7518
• A student investigates plants growing underneath a tree He lays out a tape measure on the ground, starting at the tree. He then places a quadrat on the ground. He measures the percentage of the ground in the quadrat that is covered by plants. He repeats this every metre away from the tree. The table shows his results. The student thinks that shade from the tree is affecting the plants. Explain how the student’s results show this. – 7619
• A student investigates plants growing underneath a tree. He lays out a tape measure on the ground, starting at the tree. He then places a quadrat on the ground. He measures the percentage of the ground in the quadrat that is covered by plants. He repeats this every metre away from the tree. The table shows his results. The student thinks that shade from the tree is affecting the plants. Explain how the student’s results show this. – 7602
• A student investigates the average speed at which a trolley with different loads travels down a ramp. Look at the diagram of her experiment. She releases the trolley from a distance of 2.0 m from the bottom of the ramp. The student uses a stop-clock to measure the time it takes to reach the bottom of the ramp. She calculates the average speed. Look at her results. Describe the trend shown by the results, identify problems with the experiment and describe any improvements that you would make to the experiment. – 7510
• A student investigates the effect of a crumple zone on the force exerted during a collision.The student has one trolley with a spring at the front and another trolley without a spring.After a trolley is released, it accelerates down a slope and bounces off a rigid wall.The speed of a trolley can be measured just before a collision with the wall and just after a collision with the wall.The silver foils make contact with each other during the collision, so the time they are in contact can be read from the millisecond timer.Explain how the student could investigate the effect of a crumple zone on the average force exerted during the collision.Your explanation should include, how to determine the force (you may wish to refer to an equation from the list of equations at the end of this paper),how the effect of crumple zones may be shown in the investigation and precautions that may be necessary to achieve accurate results – 8001
• A student investigates the rate of reaction between dilute hydrochloric acid and magnesium carbonate. She wants to find out how the concentration of the acid changes the rate of reaction. Fig. 18.1 shows the apparatus she uses. Carbon dioxide gas is given off in the reaction. The student measures the loss in mass every 30 seconds for 5 minutes. Another student also investigates the rate of reaction between dilute hydrochloric acid and magnesium carbonate. Fig. 18.2 shows diagrams of some of the apparatus he uses.The student also wants to find out how the concentration of the acid changes the rate of reaction. Describe the method he follows using the apparatus in Fig. 18.2. Include a labelled diagram of the set-up of the apparatus he uses. – 7565
• A student investigates the solubility of four metal oxides and four non-metal oxides in water. The student tests the pH of the solutions formed. The table shows the student’s results The student makes two conclusions. Conclusion 1: ‘All metal oxides produce alkaline solutions.’ Conclusion 2: ‘All non-metal oxides produce acidic solutions.’ Explain why the student’s conclusions are only partly correct. Use information from the table above. – 6154
• A student investigates the thermal decomposition of copper carbonate. copper carbonate → copper oxide + carbon dioxide Here is the set-up of the apparatus she uses. The student measures the mass of copper carbonate at the start of the experiment. She then measures the mass of copper oxide made. She does the experiment five times using a different mass of copper carbonate each time. Look at her results. Plot a graph of the student’s results and draw a line of best fit. – 7557
• A student is given three metals, X, Y and Z to identify. The metals are magnesium, iron and copper. Plan an investigation to identify the three metals by comparing their reactions with dilute hydrochloric acid. Your plan should give valid results. – 6150
• A student is given three metals, X, Y and Z to identify. The metals are magnesium, iron and copper. Plan an investigation to identify the three metals by comparing their reactions with dilute hydrochloric acid. Your plan should give valid results. – 6096
• A student is separating a mixture of three substances, A, B and C. Look at the table. It gives information about these substances. A and B mix together completely. Suggest how the student can separate the mixture to get pure samples of substances A, B and C. Explain in detail how each method works. – 7555
• A student made a moving-coil loudspeaker. The figure below shows a diagram of the loudspeaker. Explain how a moving-coil loudspeaker produces a sound wave. – 6074
• A student made the following hypothesis about the heart rate of smokers and non-smokers during exercise. “During exercise, the heart rate of smokers increases more than the heart rate of non-smokers.” Design an investigation that would allow you to test this hypothesis. – 7041
• A student measured the width of a solid metal cube using a digital micrometer. The figure below shows the micrometer(c) The width of the cube was 18.45 mm. The density of the cube was 8.0 × 103 kg/m3 Calculate the mass of the cube. – 6040
• A student prepared some animal cells to view using a microscope. Red blood cells are specialised animal cells. Compare the structure of a red blood cell with the structure of a plant cell.- 6019
• A student set up the apparatus shown in the diagram. Describe how they could use this apparatus to collect data to draw a force / extension graph for this spring. – 7506
• A student titrated 25.0 cm3 portions of dilute sulfuric acid with a 0.105 mol/dm3 sodium hydroxide solution. The table below shows the student’s results. The equation for the reaction is: 2 NaOH + H2SO4 ⟶ Na2SO4 + 2 H2O Calculate the concentration of the sulfuric acid in mol/dm3 Use only the student’s concordant results. Concordant results are those within 0.10 cm3 of each other – 6140
• A student wanted to find the volume of dilute hydrochloric acid that would react with 25.0 cm3 of lithium hydroxide solution. They used the equipment in Figure to carry out a rough titration and then a further two accurate titrations. Describe how the rough titration should be carried out once the dilute hydrochloric acid, lithium hydroxide solution and indicator are placed in the apparatus in Figure 7 – 9042
• A student wanted to investigate how effective three different antiseptics were at killing bacteria. The student was provided with an inoculated Petri dish prepared using the method in Figure 10 ,three different antiseptics , filter paper discs and sticky tape. Devise a plan for the student to complete this investigation. Include a control and any variables that the student would need to consider – 10031
• A student wanted to make 11.0 g of copper chloride. The equation for the reaction is: CuCO3 + 2HCl → CuCl2 + H2O + CO2 Relative atomic masses, Ar: H = 1; C = 12; O = 16; Cl = 35.5; Cu = 63.5 Calculate the mass of copper carbonate the student should react with dilute hydrochloric acid to make 11.0 g of copper chloride. – 6145
• A student wanted to make 11.0 g of copper chloride. The equation for the reaction is: CuCO3 + 2HCl → CuCl2 + H2O + CO2 Relative atomic masses, Ar: H = 1; C = 12; O = 16; Cl = 35.5; Cu = 63.5 Calculate the mass of copper carbonate the student should react with dilute hydrochloric acid to make 11.0 g of copper chloride. – 6110
• A student wants to compare the reactivity of an unknown metal, Q, with that of zinc. Both metals are more reactive than silver. The student is provided with: • silver nitrate solution • metal Q powder • zinc powder • a thermometer • normal laboratory equipment. No other chemicals are available. Describe a method the student could use to compare the reactivity of metal Q with that of zinc. Your method should give valid results. – 6149
• A student watches a ball game on the school field. The student sees the ball being hit with a bat but he hears the sound a short time after. This is because the speed of light is much greater than the speed of sound. Describe an experiment which measures the speed of sound in air. In your answer describe the measurements, calculations and procedures needed to gather accurate and reliable results. – 7521
• A substance is heated at a constant rate and its temperature is taken every minute. During the heating, the substance undergoes one change of state. The results are shown on the graph . Explain the shape of the graph in terms of the changes in the movement and arrangement of the particles as the substance is heated – 9015
• A teacher demonstrated how a magnetic field can cause a copper rod to accelerate. The teacher placed the copper rod on two brass rails in a magnetic field. The copper rod was able to move. The teacher closed the switch and the copper rod accelerated uniformly from rest for 0.15 s. The current in the copper rod was 1.7 A. mass of copper rod = 4.0 glength of copper rod in the magnetic field = 0.050 m magnetic flux density = 0.30 T Calculate the maximum possible velocity of the copper rod when it left the magnetic field. – 6007
• A teacher demonstrated how a magnetic field can cause a copper rod to accelerate. The teacher placed the copper rod on two brass rails in a magnetic field. The copper rod was able to move. The figure below shows the equipment used. The teacher closes the switch and the copper rod accelerates. Explain how Fleming’s left hand rule can be used to predict the direction in which the copper rod will move. – 6073
• A teacher demonstrated some features of waves using a ripple tank. The teacher’s measurements for the time taken for 10 wave fronts to pass the mark were: 8.4 s  7.8 s  8.1 s Calculate the mean frequency of the wave. Give your answer to 2 significant figures. – 6006
• A teacher demonstrated the relationship between the pressure in a gas and the volume of the gas. The figure below shows the equipment used. – 6037
• A teacher investigated the reaction of iron with chlorine using the apparatus in the above diagram. The word equation for the reaction is: iron + chlorine → iron chloride The teacher weighed: • the glass tube • the glass tube and iron before the reaction • the glass tube and iron chloride after the reaction. Table 2 shows the teacher’s results. – 6094
• A teacher investigated the reaction of iron with chlorine using the apparatus in the above diagram. The word equation for the reaction is: iron + chlorine → iron chloride The teacher weighed: • the glass tube • the glass tube and iron before the reaction • the glass tube and iron chloride after the reaction. Table 2 shows the teacher’s results. – 6103
• A TV has the label below on it. Calculate the current in the TV when it is turned on. Use the equation: power = potential difference × current Give your answer to 2 significant figures. – 7515
• A TV has the label below on it. The TV is turned on for 30 minutes. Calculate the energy transferred by the TV. Energy used – 7516
• A woman’s hand accidentally touches a hot object. The woman moves her hand away rapidly. Describe how the woman’s nervous system coordinates the reflex action. – 7045
• A woman’s hand accidentally touches a hot object. The woman moves her hand away rapidly. Describe how the woman’s nervous system coordinates the reflex action. – 7057
• Alkenes are obtained from crude oil using fractional distillation followed by cracking. Explain how alkenes are produced using fractional distillation followed by cracking.  – 6517
• Alpha radiation and beta radiation are also produced by radioactive decay. Compare the processes of alpha decay and beta decay. Your answer should include what each radiation is and what effect each decay has on the original nucleus.
• Ammonia is made from nitrogen and hydrogen in the Haber process Effect of temperature and pressure on the amount of ammonia at equilibrium Use the information given above and your knowledge of the Haber process and reversible reactions to help you to answer this question. State which conditions of temperature and pressure would give the highest percentage of ammonia at equilibrium. Explain why. – 6174
• Ammonia solution and dilute sulfuric acid are used to prepare pure, dry ammonium sulfate crystals.In an experiment a titration is carried out to determine the volumes of ammonia solution and dilute sulfuric acid that react together. Then an ammonium sulfate solution is prepared from which the pure, dry crystals are obtained. Describe in detail, using suitable apparatus, how this experiment should be carried out – 9031
• Ammonia solution and dilute sulfuric acid are used to prepare pure, dry ammonium sulfate crystals.In an experiment a titration is carried out to determine the volumes of ammonia solution and dilute sulfuric acid that react together.Then an ammonium sulfate solution is prepared from which the pure, dry crystals are obtained. Describe in detail, using suitable apparatus, how this experiment should be carried out – 9043
• Ammonium sulfate is a compound in fertilisers. Ammonium sulfate can be made using an industrial process or in the laboratory. In the industrial process, the following steps are used. 1. React streams of ammonia solution and sulfuric acid together. 2. Evaporate the water by passing the solution down a warm column. 3. Collect dry crystals continuously at the bottom of the column. In the laboratory, the following steps are used. 1. React ammonia solution and sulfuric acid in a conical flask. 2. Evaporate water from the solution until crystals start to form. 3. Leave to cool and crystallise further. 4. Separate the crystals using filtration. 5. Dry the crystals between pieces of filter paper. Evaluate the two methods for producing a large mass of ammonium sulfate. – 6196
• Ammonium sulfate is a salt. It is made using the reaction between the alkali ammonia and sulfuric acid. Describe how a sample of solid ammonium sulfate is prepared in a laboratory. Explain why this method is not suitable to be used industrially.  – 7568
• An aeroplane is 4000 m above the Earth’s surface. A skydiver jumps from the aeroplane and falls vertically. Figure 1 shows the distance the skydiver falls during the first 12 seconds after jumping. – 6058
• An electric car connected to a battery charger.The car has a rechargeable battery to drive its motor.The rechargeable battery provides a potential difference of 330 V and can store up to 64 MJ.It takes 8 hours for the battery to receive a full charge.Assume that the charging process is 100% efficient.The battery charger is connected to the 230 V a.c. domestic mains supply.The output voltage of the charger is 335 V and it provides a d.c. charging current. Charging stops if the charging current exceeds 15 A.Explain how electrical components in the charger can be connected together to give this type of output.
• An electric kettle was switched on. The graph below shows how the temperature of the water inside the kettle changed. The energy transferred to the water in 100 seconds was 155 000 J specific heat capacity of water = 4200 J/kg °C. Determine the mass of water in the kettle. Use the graph above. Give your answer to 2 significant figures. – 6001
• Another method of contraception is called the intrauterine device (IUD). There are two main types of IUD: • copper  • plastic. Both types of IUD are more than 99% effective. Look at Table 2.Evaluate the use of the plastic IUD as a contraceptive compared to the copper IUD. Use the information in Table 2 – 7052
• Another student carried out the titration accurately. 12.15 cm3 of dilute sulfuric acid with a concentration of 0.140 mol dm–3 reacted completely with 25.00 cm3 of potassium hydroxide solution. H2SO4 + 2KOH → K2SO4 + 2H2O . Calculate the concentration of this potassium hydroxide solution – 9040
• Another student investigated the rate of reaction by measuring the change in mass. Figure 3 shows the graph plotted from this student’s results. Use Figure 3 to calculate the mean rate of the reaction up to the time the reaction is complete. Give your answer to three significant figures. – 6171
• Another student investigated the rate of reaction by measuring the change in mass. Figure 3 shows the graph plotted from this student’s results. Use Figure 3 to determine the rate of reaction at 150 seconds. Show your working on Figure 3. Give your answer in standard form. – 6172
• Another student set up the apparatus correctly. Figure 2 shows the student’s results. The result for dye D is not shown. Explain how the different dyes in X are separated by paper chromatography. – 6178
• Arthritis is a condition that occurs when cells in joints get damaged or destroyed. Stem cell therapy can be used to treat arthritis. Discuss the benefits and risks of using stem cell therapy to treat arthritis – 10007
• At the end of the stable stage of its life a star will change. Describe and explain the changes that could take place. – 6008
• Atoms contain three types of particles. Some substances are radioactive. They may emit alpha or beta particles. Describe the characteristics of alpha particles and beta particles in terms of their:• structure • penetration through air and other materials • deflection in an electric field. – 6004
•  Explain how different types of organism defend themselves against microorganisms. – 7026
• Before the electrolysis, the masses of the electrodes were determined. After the electrolysis, the electrodes were washed and dried and their masses re-determined. Figure 6 shows these masses and the resulting changes in masses of the electrodes. Explain these results. – 9020
• Bluebell plants grow in woodlands in the UK. • Bluebells can reproduce sexually by producing seeds. • Bluebells can also reproduce asexually by making new bulbs. Explain why sexual reproduction is an advantage for bluebells. – 7002
• Bromine reacts with methane in sunlight. The diagram below shows the displayed formulae for the reaction of bromine with methane. – 6095
• Calcium carbonate thermally decomposes to make calcium oxide and carbon dioxide. CaCO3 → CaO + CO2 Calculate the mass of calcium carbonate needed to make 209g of calcium oxide. (A r: Ca = 40.1, C = 12.0, O = 16.0). Give your answer to 3 significant figures. Mass of calcium carbonate – 7554
• Calcium chloride can be prepared by the reaction of calcium with chlorine gas. Figure shows some properties of calcium, chlorine and calcium chloride.Explain, in terms of bonding and structure, why the properties of the product, calcium chloride, are different from the properties of the reactants, calcium and chlorine – 9011
• Calculate the mass of this piece of wood. Show your working and give the units. – 7501
• Calculate the mean rate of reaction between 30 and 250 seconds for coarse manganese dioxide lumps. Use the figure and the equation: Give your answer to 3 significant figures. Volume of oxygen formed – 6128
• Calculate the percentage atom economy for the production of silver iodide in this reaction. The equation for the reaction is:AgNO3(aq) + NaI(aq) → AgI(s) + NaNO3(aq) Give your answer to 3 significant figures. Relative formula masses: (Mr): AgNO3 = 170 NaI = 150 AgI = 235 NaNO3 = 85 – 6117
• Calculate the percentage atom economy for the production of silver iodide in this reaction. The equation for the reaction is:Give your answer to 3 significant figures. Relative formula masses: (Mr): AgNO3 = 170 NaI = 150 AgI = 235 NaNO3 = 85 – 6100
• Chemical tests are used to identify gases, anions and cations. Draw straight lines to match the gas to the correct chemical test used in analysis. – 7562
• Colistin is an antibiotic used to treat infections in the bloodstream.Some bacteria are resistant to Colistin. Explain how these bacteria have become resistant to Colistin – 10022
• Commercially, hundreds of pink-flowered snapdragon plants can be produced from one pink-flowered plant. Figure 2 shows a tissue culture technique used for producing many plants from one plant. Give a reason for each of the following steps shown in Figure 2. Several groups of cells are scraped off the leaf – 7071
• Compare how each type of diabetes is caused. Suggest how each type of diabetes can be treated.  – 7054
• Compare the structure and bonding of the three compounds carbon dioxide , magnesium oxide and silicon dioxide
• Compare the structure and function of xylem tissue and phloem tissue. – 7018
• Complete Figure 2. You should: • label the x-axis • use a suitable scale • plot the data from the table above and your answer to part (d) • draw a line of best fit. Figure 2 – 7035
• Complete the graph below using data from the table above. You should: • label the y-axis • use a suitable scale for the y-axis • plot the mean data from the table above for temperatures from 25 °C to 45 °C • draw a line of best fit. – 7034
• Complete the line graph below for person S. You should: • add the scale to the x axis • label the x axis. – 7040
• Complete the sentences about an atom. Use words from the list. You may use each word once, more than once, or not at all. Atom Electrons Negatively Neutrons Nucleus Orbits Positively Protons – 7502
• Complete the table below. Calculate the value for Rf for dye A. Use the equation Rf =distance moved by dye A / distance moved by solvent . Give your answer to two significant figure – 6131
• Complete the table to show the results when a cell divides by mitosis or meiosis in humans. Human body cells, except gametes, have 23 pairs of chromosomes. – 10002
• Covalent substances can be simple molecular covalent or giant covalent. The arrangement of carbon atoms in diamond, graphene and a fullerene (C60). Consider these three substances. Explain, in terms of their structures and bonding, their relative melting points, strengths and abilities to conduct electricity – 9012
• Decay occurs in a compost heap. The figure below shows a compost heap. Describe:  • how microorganisms in the layers of soil help to recycle chemicals in the dead plants • how the chemicals are used again by living plants. – 6025
• Describe a method to make pure, dry crystals of magnesium sulfate from a metal oxide and a dilute acid – 6139
• Describe a safe method for making pure crystals of copper sulfate from copper carbonate and dilute sulfuric acid. Use the information in the figure above to help you. In your method you should name all of the apparatus you will use. – 6118
• Describe an investigation to find out how the nature of a surface affects the amount of thermal energy absorbed by the surface. You should use the apparatus in Figure and any additional items you choose. Each can in Figure has a bung in the top with a hole in it. You may use a diagram if it helps your answer – 8012
• Describe how a teacher should use a Geiger-Müller (GM) tube to compare the count-rates from two different radioactive rocks – 8023
• Describe how hormones control the menstrual cycle. – 7046
• Describe how hormones control the menstrual cycle. – 7058
• Describe how the ancestors of modern lemurs may have evolved into the Describe how the ancestors of modern lemurs may have evolved into the -7077
• Describe how the human body: • prevents pathogens from entering • defends itself against pathogens inside the body. – 7023
• Describe how the process of distillation shown in Figure 2 produces pure water from salt solution.  – 6085
• Describe how the teacher could show how far beta particles travel in air – 8018
• Describe the experimental procedure to carry out a titration to find the exact volume of sulfuric acid needed to neutralise 25.0 cm3 of sodium hydroxide solution and obtain pure, dry crystals of sodium sulfate – 9044
• Determine the number of atoms of copper produced when copper nitrate solution is electrolysed for 20 minutes at a current of 0.6 A Give your answer to 3 significant figures. Use Figure 2. Relative atomic mass (Ar): Cu = 63.5 The Avogadro constant = 6.02 × 1023 per mole- 6125
• Different parts of the body’s have natural defence mechanisms to stop pathogens infecting the body. These defences include: • skin • tears  • secretions from the stomach. Describe how each defence stops pathogens infecting the body. – 7624
• Diffusion is an important process in animals and plants.Diffusion also happens in the human lungs. Figure 2 shows the human breathing system. Explain how the human lungs are adapted for efficient exchange of gases by diffusion. – 7011
• Discuss the advantages and disadvantages of sexual reproduction and asexual reproduction – 10016
• Disposable cups are made from coated paper or poly(styrene). The table below shows information on the life cycle assessments (LCAs) of disposable cups. – 6018
• Disposable cups are made from coated paper or poly(styrene). The table below shows information on the life cycle assessments (LCAs) of disposable cups. Evaluate the use of coated paper compared with poly(styrene) to make disposable cups. Use the table above and your knowledge and understanding of LCAs. – 6190
• DNA is found in the nucleus of cells. Describe the structure of DNA and how it can be extracted from plant cells – 10017
• Domestic UK electrical wiring uses live, neutral and earth wires. Complete the two empty boxes and then draw lines to match up the wires to their colour and function. – 7531
• Dr Williams shows her class an experiment with radioactivity. She uses three different radioactive sources an alpha , beta and gamma emitter. She uses different thicknesses of sheets of paper between the source and the sensor. Each radioactive source emits only one type of radiation. Use the data to identify and explain which radiation comes from sources X, Y and Z. Comment on how useful each source is for detecting the thickness of sheets of paper up to 2 mm.
• Dupuytren’s is a disorder that affects the hands. The diagram below shows the inheritance of Dupuytren’s in one family Person 7 and person 8 in the diagram above are expecting a fourth child. What is the probability of the child having Dupuytren’s? You should: • draw a Punnett square diagram • identify which offspring have Dupuytren’s – 7000
• During one year, 2.42 × 10¹⁹ J of energy was transferred from National Grid. Some houses use solar cells to generate electricity. When the energy generated by the solar cells is not needed, the energy is stored in a battery.A house has solar cells on the roof. 31 000 C of charge flows through the cable from the solar cells to the battery in a 24 hour period. The potential difference in the circuit is 3.3 V. Determine the power lost due to heating in the cable. Give your answer to 2 significant figures.
• Endometriosis is a condition where the cells that normally line the uterus (womb) can move to other parts of the body. During the menstrual cycle the cells that have moved can react in the normal way to the hormones controlling menstruation. This can cause a number of problems including fatigue and pain. Using the information from the graph as well as your own knowledge explain what happens to the cells that have moved and how doctors could treat the condition using sex hormones. – 7614
• Energy from the nuclei of atoms can be used in medical diagnosis and treatment.Some tumours inside the body can be treated by using either alpha radiation or gamma radiation. Explain why the source of alpha radiation is usually inside the body but the source of gamma radiation can be outside the body – 8024
• Energy sources used in Canada in 2014 and a prediction for 2040.Discuss the effects on the environment of two predicted changes between 2014 and 2040 – 8005
• Ethane is an alkane and ethene is an alkene. The diagram below shows the displayed structural formulae of ethane and of – 6015
• Ethane is an alkane and ethene is an alkene. The diagram below shows the displayed structural formulae of ethane and of ethene. Compare ethane with ethene. You should refer to: • their structure and bonding • their reactions. – 6155
• Ethanol can be produced from ethene and steam. The equation for the reaction is: C2H4(g) + H2O(g) ⇌ C2H5OH(g) The forward reaction is exothermic. Explain how the conditions for this reaction should be chosen to produce ethanol as economically as possible.Empty Page for ASKNAt – 6160
• Explain how impulses are transmitted at synapses – 10012
• Explain how the change in blood flow to the athlete’s muscles helps him to run – 7042
• Explain how the different dyes in X are separated by paper chromatography – 6132
• Explain how the human circulatory system is adapted to: • supply oxygen to the tissues • remove waste products from tissues – 7013
• Explain how vibrations from earthquakes may be used to study the core of the Earth – 8006
• Explain the functions of the two types of cell in the retina that detect light – 10010
• Explain the ways the man’s body has responded to the exercise. Use information from the graph above. – 7038
• Explain why graphite is a good electrical conductor , soft and slippery. You should answer in terms of structure and bonding.
• Explain why the reactivity of elements changes going down Group 1 – 6148
• Explain why the reactivity of elements changes going down Group 1. – 6091
• Fahmida does three chemical tests on an unknown solution. Look at her results. Which ions are present in the solution? Choose from: calcium hydrogen iron(II) chloride sulfate Explain your answer. – 7563
• Farming techniques have changed in recent years. Describe: why more land is being used for farming how increased farming has decreased biodiversity – 7094
• Farming techniques have changed in recent years. In 1900 the human population was 1.6 billion. Describe: • why more land is being used for farming • how increased farming has decreased biodiversity – 7089
• Fig. 20.1 shows thinking, braking and stopping distances for the same car travelling at different speeds. Explain why the stopping distances are different for each speed in Fig. 20.1 – 7525
• Figure 1 shows a boat floating on the sea. The boat is stationary. Figure 2 shows part of the free body diagram for the boat. Complete the free body diagram for the boat. – 6062
• Figure 1 shows a cross section of a leaf. Compare the structure and function of xylem tissue and phloem tissue. – 7007
• Figure 1 shows a flightless bird called the dodo (Raphus cucullatus). The dodo: • was 1 m tall • had a mass of 20 kg • lived in rainforests on a tropical island • ate fruits • made its nest on the ground. A female dodo laid only one egg each year. Humans arrived on the island in the year 1507. By 1681 the dodo was extinct. The rainforest contains: • 750 species of trees • 400 species of birds • 150 species of butterflies • many other species of plants and animals. Explain how the pattern of cutting down trees shown in Figure 2 stops the biodiversity of the rainforest being reduced. – 7090
• Figure 1 shows a reflex in the iris of the human eye in response to changes in light levels. Describe the changes in the pupil and iris going from A to B in Figure 1. Explain how these changes occur. Refer to the changes in light level in your answer. – 7062
• Figure 1 shows an outline of the modern periodic table. J, L, M, Q and R represent elements in the periodic table. (f) In the 1860s scientists were trying to organise elements. Figure 2 shows the table published by John Newlands in 1865. The elements are arranged in order of their atomic weights.- 6030
• Figure 1 shows the displayed formula equation for the reaction of hydrogen sulfide with oxygen. Figure 1 2 H – S – H + 3 O=O ….> 2 H-O-H + 2 O=S=O. – 6013
• Figure 1 shows ultrasound being used to detect a hidden crack in a solid aluminium object. The transmitted and reflected pulses of ultrasound are shown on the screen. Ultrasound travels at 6300 m/s in aluminium. Determine the depth of the crack below the top surface of the aluminium.- 6068
• Figure 1 shows ultrasound being used to detect a hidden crack in a solid aluminium object. The transmitted and reflected pulses of ultrasound are shown on the screen. Ultrasound travels at 6300 m/s in aluminium. Determine the depth of the crack below the top surface of the aluminium. Use information from Figure 1. Give your answer to two significant figures.- 6077
• Figure 2 shows a child on a playground swing. The playground has a rubber safety surface. A child of mass 32 kg jumped from the swing. When the child reached the ground she took 180 milliseconds to slow down and stop.  During this time an average force of 800 N was exerted on her by the ground. Calculate the velocity of the child when she first touched the ground.  Use the Physics Equations Sheet. – 6057
• Figure 2 shows an axolotl. Explain why an axolotl may die in water with a low concentration of oxygen. – 7001
• Figure 2 shows an ultrasound transmitter sending waves into a patient’s body. The waves enter the body and move towards a kidney. The transmitter also detects the ultrasound waves. The transmitter is connected to an oscilloscope. Figure 3 shows the trace on the screen of the oscilloscope. J represents the intensity of the waves emitted by the transmitter. Explain the intensities at K, L and M. – T
• Figure 2 shows how a small weight placed on the insulating bar makes the wire X go back and balance in its original position. The wire X is 5 cm long and carries a current of 1.5 A. The small weight causes a clockwise moment of 4.8 × 10−4 Nm. Calculate the magnetic flux density where the wire X is positioned Give the unit. – 6081
• Figure 2 shows how the length of a satellite orbit depends on the height of the satellite above the Earth’s surface. A satellite orbits 300 km above the Earth’s surface at a speed of 7.73 km/s. Calculate how many complete orbits of the Earth the satellite will make in 24 hours. – 6083
• Figure 2 shows some structures involved in the coordination of a reflex action. Describe how the structures shown in Figure 2 help to coordinate a reflex action. – 7061
• Figure 2 shows the biomass of adult herring in the North Sea between 1950 and 1990. Too many herring were caught in the 1960s.Calculate the percentage decrease in the biomass of adult herring between 1960 and 1970. Use the equation: Give your answer to the nearest whole number. – 7036
• Figure 2 shows the displayed formula equation for the reaction of hydrogen sulfide with oxygen. In the reaction the energy released forming new bonds is 1034 kJ/mol greater than the energy needed to break existing bonds. Calculate the bond energy X for the bond. Use Figure 2 and the table above. – 6165
• Figure 2 shows the displayed formula equation for the reaction of hydrogen sulfide with oxygen. The table below shows some of the bond energies. In the reaction the energy released forming new bonds is 1034 kJ/mol greater than the energy needed to break existing bonds. Calculate the bond energy X for the bond. Use Figure 2 and the table above. -6111
• Figure 2 shows the feeding relationships between the microorganisms in the sprinkler bed The bacteria are decomposers. Figure 2 shows that the bacteria change organic matter into carbon dioxide and inorganic mineral ions. Describe how the bacteria do this. – 7085
• Figure 2 shows the inheritance of sickle cell anaemia in one family Persons 8 and 9 in Figure 2 are expecting a second child. Determine the probability that the child will be a girl with sickle cell trait. You should: • draw a Punnett square diagram • identify the phenotype of each offspring genotype • use the symbols: HA = normal haemoglobin allele HS = mutated haemoglobin allele. – 7068
• Figure 2 shows the inside parts of the alternator. The handle of the alternator is turned, causing the coil to rotate. Explain why an alternating current is induced in the coil. – 6076
• Figure 2 shows the parts of a moving-coil microphone. Explain how a moving-coil microphone works. – 6069
• Figure 2 shows the parts of a moving-coil microphone. Explain how a moving-coil microphone works. – 6078
• Figure 2 shows the parts of a pregnancy test strip The pregnancy test strip will show a positive test result when a woman is pregnant. Explain how the pregnancy test strip works to show a positive result. – 7029
• Figure 2 shows the percentage (%) survival of large mammal species in four areas of the world. The time at which humans first appeared in each of the four areas is also shown. A mass extinction is a rapid decrease in biodiversity on Earth. A student stated: ‘The data in Figure 2 shows that humans caused mass extinctions.’ Evaluate the student’s statement. – 7065
• Figure 2 shows the total volume of water lost from a plant over 6 hours. Determine the rate of water loss at 12:00  Use the tangent on the graph above. Give your answer: • in cm3 per minute • in standard form. – 7008
• Figure 2 shows the total volume of water lost from a plant over 6 hours. Determine the rate of water loss at 12:00 Use the tangent on the graph above. Give your answer: • in cm3 per minute  • in standard form. – 7019
• Figure 2 shows what happens to the electrons in the outer shells when a sodium atom reacts with a fluorine atom. The dots (•) and crosses (×) represent electrons. – 6090
• Figure 3 shows a patient who has been injected with a radioactive source for medical diagnosis. – 6043
• Figure 3 shows the reaction between ethene and chlorine and is similar to the reaction between ethene and bromine. The more energy levels (shells) of electrons an atom has, the weaker the covalent bonds that it forms.”Use the above statement to predict and explain how the overall energy change for the reaction of ethene with chlorine will differ from the overall energy change for the reaction of ethene with bromine. – 6168
• Figure 4 is a map of the Galapagos Islands. On Isabela Island, the medium ground finch and the small ground finch are found. On Daphne Island, only the medium ground finch is found. On Crossman Island, only the small ground finch is found. Figure 5 shows how the beak depth of each species varies on each island. The medium ground finch and the small ground finch both feed on seeds. The size of seeds eaten by each bird depends on the depth of the bird’s beak. The range of beak depth of medium ground finches on Isabela Island is different from the range on Daphne Island. Explain what might have caused this difference – 7076
• Figure shows a way of projecting a small trolley up a sloping track. When the button is pressed, a spring is released in P that projects the trolley up the track. The trolley travels up the track, stops and then rolls back down.A student investigates how the mass of the trolley affects the maximum vertical height, h, reached by the trolley. State the measurements the student should make to complete the investigation. You should make use of the equipment shown in Figure 5 and any other equipment that is needed – 8004.
• Figure shows some properties of three substances, A, B and C. Deduce, using the information in Figure , the structure and bonding of substances A, B and C, explaining their properties in terms of their structure and bonding – 9009.
• Figure shows two defects of the eye. Describe the causes of short-sightedness and long-sightedness. Use information from Figure 12 to help with your answer – 10008
• Figure  shows how the velocity of the cyclist changes during the first part of a journey along a straight and level road. During this part of the journey the force applied by the cyclist to the bicycle pedals is constant. – 6005
• Finish these sentences to explain what is happening in the body of a female during the menstrual cycle. The pituitary gland in the —————————-releases the hormone FSH. FSH causes an ——————-releases the hormone FSH. FSH also causes the follicle to release the hormone ————————-. After ovulation, the empty follicle releases another hormone called ——————-. – 7615
• Fluorine is the most reactive element in group 7 of the Periodic Table. Fluorine reacts with all the other elements in the Periodic Table except some of the noble gases. It does not react with helium, neon and argon, but it does react with xenon. Many substances burst into flames when exposed to fluorine. – 6031
• Fossil fuels are burned in car engines. Explain how reducing the amount of sulfur in fossil fuels reduces the erosion of limestone. – 6181
• Four students run in different races. Use the information in the table to describe and compare the motion of the four students. Use the data in your answer. – 7509
• Fusion and fission are nuclear reactions in which large amounts of energy are released. Nuclear fission is used in nuclear reactors in some power stations. In the reactor, a fission chain reaction is maintained and controlled to produce a supply of energy to generate electricity. Explain how the graphite core and the movable rods are used to maintain and control the chain reaction – 8017.
• Gamma radiation is produced by radioactive decay. Alpha radiation and beta radiation are also produced by radioactive decay. Compare the processes of alpha decay and beta decay. The answer should include what each radiation is and what effect each decay has on the original nucleus – 8020
• Gonorrhoea is a sexually transmitted bacterial infection. Figure shows the number of people diagnosed with gonorrhoea in the UK. Explain how gonorrhoea is transmitted and how the number of people infected can be reduced. Use data from the graph to justify why it is necessary to reduce the number of people infected – 10033
• Hedgehogs are covered in small spines. When they are frightened they often roll up into a ball and keep still Scientists have noticed that a new type of hedgehog is increasing in numbers in cities. These hedgehogs do not roll up. They run away when frightened. The scientists think that genes control this behaviour. Explain how this type of hedgehog may become more common in cities. Use ideas about natural selection – 7618
• Homeostasis controls the internal conditions of the body. Explain how blood glucose levels are controlled in the body of someone who does not have diabetes. – 7053
• Humans keep their internal conditions almost constant.Body temperature is kept within a narrow range. When the core body temperature is too low, this is detected by the thermoregulatory centre in the brain. Describe how the body responds when a decrease in core body temperature is detected. – 6023
• Humans keep their internal conditions almost constant.Body temperature is kept within a narrow range. When the core body temperature is too low, this is detected by the thermoregulatory centre in the brain. Describe how the body responds when a decrease in core body temperature is detected. – 7044
• Hydrated copper sulfate has the formula CuSO4.5H2O.The formula tells us that each mole of copper sulfate contains 5 moles of water. A sample of CuSO4.5H2O was heated gently until all the water was removed to form anhydrous copper sulfate, CuSO4.CuSO4.5H2O → CuSO4 + 5H2O.The mass of water formed was 4.5 g.Calculate the mass of hydrated copper sulfate that was heated – 9002
• Hydrated copper sulfate, CuSO4.5H2O, is a blue solid. Anhydrous copper sulfate, CuSO4, is a white solid. Heat energy is needed to convert hydrated copper sulfate to anhydrous copper sulfate. This is a reversible reaction. Devise an experiment to show that this is a reversible reaction. – 9024
• Hydrogen-oxygen fuel cells can be used to provide electrical energy in a spacecraft. The reaction that takes place in the fuel cell ishydrogen + oxygen → water . Evaluate the advantages and disadvantages of providing electrical energy in a spacecraft using hydrogen-oxygen fuel cells rather than chemical cells – 9029
• Hypercholesterolemia (HC) is caused by a dominant allele on chromosome 19. This allele has mutations which cause a change in the order of DNA nucleotides. People with HC are more likely to get heart disease. The diagram shows the heart of a person who has heart disease. The graph shows the results of a study of men aged 30 to 49. The study measured the cholesterol levels in the blood of the men. It also recorded if the men developed signs of heart disease. Explain the possible link between cholesterol and heart disease and if this link is supported by the graph. Use evidence from the diagram and the graph in your answer. – 7604
• Impure copper can be purified using electrolysis. In this electrolysis • the anode is made of impure copper • the cathode is made from pure copper • the electrolyte is copper sulphate solution. The apparatus at the start of the experiment is shown in Figure 10. – 9021
• In 2003, the first complete human genome was sequenced. The genomes of different people have small changes in the sequence of the DNA bases. Describe how these changes in DNA sequence can affect the individuals and how sequencing a person’s genome could influence their medical treatments – 10018
• In 2014 the Ebola virus killed almost 8000 people in Africa. Drug companies have developed a new drug to treat Ebola. Explain what testing must be done before this new drug can be used to treat people. – 7027
• In 2017, a new strain of Klebsiella pneumoniae bacteria was discovered that was resistant to 26 different antibiotics.Explain how Klebsiella pneumoniae bacteria developed resistance to antibiotics – 10023
• In an experiment magnesium hydroxide powder is added in 0.1 g portions to 25 cm3 of dilute hydrochloric acid until the magnesium hydroxide is just in excess. Universal indicator paper can be used to test the pH of the solution after each addition of magnesium hydroxide. State and explain how the pH changes as the magnesium hydroxide is added to the dilute hydrochloric acid. – 9019
• In another stage in the production of nitric acid, ammonia is reacted with oxygen to form nitrogen oxide and water. Heat energy is given out when ammonia reacts with oxygen. The conditions chosen for the reaction are excess air, rather than just the right amount , a pressure of 10 atm, rather than atmospheric pressure and a temperature of 900 °C, rather than room temperature. Explain the effect of the conditions chosen on the equilibrium yield of nitrogen oxide and on the rate of attainment of equilibrium – 9034
• In one stage of the production of nitric acid, nitrogen oxide, NO, is reacted with oxygen to make nitrogen dioxide. Calculate the minimum volume of air, measured at room temperature and pressure, required to react with 1000 g nitrogen oxide to form nitrogen dioxide. Assume that the air contains 20% oxygen by volume. (relative atomic masses: N = 14, O = 16 , 1 mol of gas occupies 24 dm3 at room temperature and pressure) – 9041
• In Stage 2, 40 kg of titanium chloride was added to 20 kg of sodium. The equation for the reaction is: Relative atomic masses (Ar): Na = 23 Cl = 35.5 Ti = 48 Explain why titanium chloride is the limiting reactant. You must show your working. -6106
• In the early 20th century, scientists developed an alpha particle scattering experiment using gold foil. The diagram shows the paths of some of the alpha particles in the alpha particle scattering experiment. – 6046
• In the periodic table, the transition elements and Group 1 elements are metals. Some of the properties of two transition elements and two Group 1 elements are shown in the table below. Use your own knowledge and the data in the table above to compare the chemical and physical properties of transition elements and Group 1 elements.- 6009
• In the periodic table, the transition elements and Group 1 elements are metals. Some of the properties of two transition elements and two Group 1 elements are shown in the table below. Use your own knowledge and the data in the table above to compare the chemical and physical properties of transition elements and Group 1 elements.- 6098
• In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. A student has to check if two samples of hydrochloric acid, A and B, are the same concentration. Describe how the student could use the apparatus and the solutions in the diagram below to carry out titrations. – 6146
• In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Light intensity, carbon dioxide concentration and temperature are three factors that affect the rate of photosynthesis. How would you investigate the effect of light intensity on the rate of photosynthesis? The image below shows some of the apparatus you might use You should include details of: • how you would set up the apparatus and the materials you would use • the measurements you would make • how you could make this a fair test. – 7037
• In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Most car engines use petrol as a fuel. • Petrol is produced from the fractional distillation of crude oil.  • Crude oil is a mixture of hydrocarbons. • Sulfur is an impurity in crude oil. Car engines could be developed to burn hydrogen as a fuel. • Hydrogen is produced from natural gas.  • Natural gas is mainly methane. Table 2 shows information about petrol and hydrogen. – 6158
• In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Plants transport many substances between their leaves and roots. The diagram below shows the direction of movement of substances through a plant. Describe how ions, water and sugar are obtained and transported through plants. In your answer you should refer to materials moving upwards in a plant and to materials moving downwards in a plant.- 7022
• In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. Plants transport many substances between their leaves and roots. The diagram below shows the direction of movement of substances through a plant.Describe how ions, water and sugar are obtained and transported through plants. In your answer you should refer to materials moving upwards in a plant and to materials moving downwards in a plant.  – 7014
• In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate. The diagram shows the structure of a vacuum flask. A vacuum flask is designed to reduce the rate of energy transfer by heating processes. Describe how the design of a vacuum flask keeps the liquid inside hot – T
• Iron chloride is produced by heating iron in chlorine gas. The equation for the reaction is: 2 Fe + 3 Cl2 → 2 FeCl3 Calculate the volume of chlorine needed to react with 14 g of iron. You should calculate: • the number of moles of iron used • the number of moles of chlorine that react with 14 g of iron • the volume of chlorine needed. Relative atomic mass (Ar): Fe = 56 The volume of 1 mole of gas = 24 dm3 – 6136
• It is important to keep the blood glucose concentration within narrow limits. (a) A person eats a meal containing a lot of carbohydrate. This causes an increase in the person’s blood glucose concentration. Explain how the hormones insulin and glucagon control the person’s blood glucose concentration after the meal. – 7049
• Kayvan investigates the effect of changing the pressure and changing the temperature on this reaction. The table shows the percentage yield of methane in the equilibrium mixture under different conditions. Describe what happens to the percentage yield as the pressure and temperature change and explain the effect of increasing the pressure on the rate of reaction. – 7566
• Lead can be obtained by heating its oxide with carbon. The balanced equation for the reaction is 2PbO + C → 2Pb + CO2 .Calculate the atom economy for the production of lead in this reaction. (relative atomic masses: C = 12, O = 16, Pb = 207 relative formula masses: PbO = 223, CO2 = 44). Give your answer to two significant figures – 9038
• Lead is most commonly extracted from an ore called galena, PbS. Extracting lead from the galena ore involves two steps. Step 1: The galena ore is roasted in air to produce lead oxide, PbO. Step 2: The lead oxide is heated in a blast furnace with carbon. The reaction in step 1 is an exothermic reaction. Draw a labelled reaction profile diagram for an exothermic reaction. Label the activation energy and the energy change on your diagram. – 7556
• Light intensity, carbon dioxide concentration and temperature are three factors that affect the rate of photosynthesis. How would you investigate the effect of light intensity on the rate of photosynthesis? The image below shows some of the apparatus you might use. – 6022
• Light is usually described as a wave. Light can also be described as a stream of particles. These are two different scientific models of light. (c) Sometimes an old scientific model is replaced by a new model. Explain why scientists replace an old scientific model with a new model. Include an example from Physics in your answer. – 6070
• Look at Fig. 20.2 which shows two people riding on boards. Person A is riding a board on sand in a hot desert. Person B is riding a board on snow. Explain the different problems of temperature regulation for these two people and give examples of the ways their bodies solve these problems. – 7605
• Look at the table. It shows information about some atoms and ions. Particle C has the electronic structure 2.8.7. What does this tell you about the position of particle C in the Periodic Table? Explain your answer. – 7552
• Magnesium carbonate has the formula MgCO3. A student has two separate test tubes containing sulfuric acid. The student adds a spatula measure of magnesium carbonate, MgCO3, to the first test tube and a piece of magnesium to the second test tube. Explain what the student would see in each test tube and the tests that they should carry out to identify the gases produced. Your answer should include word equations for the reactions that would take place. – 9017
• Many people have breathing problems because they are allergic to cats. The allergy is caused by a chemical called Fel D1. Different cats produce different amounts of Fel D1. A cat has been bred so that it does not produce Fel D1. The cat does not cause an allergic reaction. Explain how the cat has been produced using selective breeding. – 7078
• Many scientists think that global air temperature is related to the concentration of carbon dioxide in the atmosphere. The graph below shows changes in global air temperature and changes in the concentration of carbon dioxide in the atmosphere. Evaluate evidence for and against the theory that an increase in the concentration of carbon dioxide in the atmosphere causes an increase in air temperature. Use data from the graph above and your own knowledge. – 7092
• Marble chips are mainly calcium carbonate (CaCO3). A student investigated the rate of reaction between marble chips and hydrochloric acid (HCl). Figure 1 shows the apparatus the student used.Explain, in terms of particles, how and why the rate of reaction changes during the reaction of calcium carbonate with hydrochloric acid. – 6170
• Melting points of two substances, A and B, and the abilities of the substances to conduct an electric current when solid and when molten. One of the substances has an ionic structure and one has a simple molecular, covalent structure. Explain, in terms of bonding and the forces between the particles, the relative melting points and abilities to conduct the electric current of substances A and B – 9010.
• Microorganisms cause infections. The human body has many ways of defending itself against microorganisms In 2014 the Ebola virus killed almost 8000 people in Africa. Drug companies have developed a new drug to treat Ebola. Explain what testing must be done before this new drug can be used to treat people. – 6021
• Monoclonal antibodies (mAbs) are usually made using mouse lymphocytes. In a laboratory the human lymphocyte mAbs were injected into animals infected with Candida albicans.The mAbs caused increased phagocytosis of the Candida albicans pathogens. It has been shown that this mAbs treatment is effective in the laboratory using both: • infected tissue culture cells • infected live animals. The mAbs treatment for Candida albicans is now ready for clinical trials on people. Describe how the clinical trials should be carried out. – 7028
• More than two thousand years ago the Earth was believed to be at the centre of the universe as shown in Figure. The planets, the Moon and the Sun were believed to be in orbit around the Earth. In 1543 Nicolaus Copernicus proposed that the Earth was a planet, and that the Earth and the other planets orbit around the Sun. Discuss how evidence has changed our views of the universe – 8025
• Most metals are extracted from ores found in the Earth’s crust. The method used to extract a metal from its ore is linked to the reactivity of the metal. Part of the reactivity series is shown in Figure 14. Aluminium is extracted from its ore by electrolysis. Iron is extracted from its ore by heating with carbon. Both metals can also be obtained by recycling. Explain the advantages of recycling aluminium and iron rather than extracting them from their ores. – 9022
• MRSA is a bacterium that has evolved to become resistant to antibiotics. With reference to Darwin’s theory of evolution by natural selection, explain how MRSA bacteria have evolved to become resistant to antibiotics – 10024
• Mycoprotein is one type of food that is mass-produced. Figure 2 shows a fermenter used to produce mycoprotein. Describe how mycoprotein is produced. – 7004
• New varieties of potato plant can be produced by selective breeding. Explain how selective breeding of the two varieties of potato plants can produce new potato plants that are all faster growing and produce many, large potatoes – 10028
• Nuclear fission and nuclear fusion are two non-renewable sources of energy. Compare nuclear fission and nuclear fusion as possible sources of energy for generating electricity using a nuclear reactor – 8016.
• Nuclear fission and nuclear fusion are two non-renewable sources of energy. Compare nuclear fission and nuclear fusion as possible sources of energy for generating electricity using a nuclear reactor. Your comparison should refer to the differences between nuclear fission and nuclear fusion and the relative advantages and difficulties involved in using these sources.
• Nuclear fission and nuclear fusion are two processes that release energy. The following nuclear equation represents the fission of uranium-235 (U-235). – 6045
• Nuclear power stations generate electricity through nuclear fission. Electricity can also be generated by burning shale gas. Describe the process of nuclear fission. – 6044
• Nuclear power stations generate electricity through nuclear fission. Electricity can also be generated by burning shale gas.(c) Describe the process of nuclear fission. – 6053
• Oil contains carbon and some sulfur When oil is burned, the products of combustion may be released into the atmosphere. Explain the environmental effects of releasing these products of combustion into the atmosphere. – 6180
• Oil contains carbon and some sulfur. When oil is burned, the products of combustion may be released into the atmosphere. Explain the environmental effects of releasing these products of combustion into the atmosphere.- 6184
• One cause of colour blindness is a change in the DNA sequence of a gene. This results in the production of a different protein in cone cells in the retina of the eye. Explain how a change in the DNA sequence of a gene can result in the production of a different protein – 10019
• One lift uses 50 000 J for a 12 s journey. Calculate the power of the lift. Give your answer to 1 decimal place. – 7514
• Oxygen enters red blood cells by diffusion. Describe and explain how red blood cells are adapted for the efficient uptake and transport of oxygen. – 7608
• Particle C has the electronic structure 2.8.7. What does this tell you about the position of particle C in the Periodic Table? Explain your answer.  – 7551
• Paul suggests this method for preparing zinc nitrate. Paul’s method will not make a pure dry sample of zinc nitrate. What improvements should Paul make to the method to make sure that: 4. the reaction is complete 5. the zinc nitrate can be separated from the nitric acid and the zinc oxide? Explain your answer. – 7561
• Penicillin, isolated from a fungus, was the first antibiotic used to treat bacterial infections and is still widely used today. Scientists have genetically engineered bacteria to produce large amounts of penicillin. Describe how scientists would produce a genetically modified bacterium that produces penicillin – 10026
• People with kidney failure can have dialysis or a kidney transplant. Dialysis is often needed 3 times each week and can take over 4 hours each time. Dialysis usually happens in a hospital. Kidney transplants require a donor and major surgery. Describe the advantages and disadvantages of having a kidney transplant instead of having dialysis. – 7047
• People with kidney failure can have dialysis or a kidney transplant. Dialysis is often needed 3 times each week and can take over 4 hours each time. Dialysis usually happens in a hospital. Kidney transplants require a donor and major surgery. Describe the advantages and disadvantages of having a kidney transplant instead of having dialysis.  – 7043
• Phil investigates some exothermic and endothermic reactions. He measures the temperature changes during some chemical reactions. Look at the table. It shows his results. What can you conclude about the type of energy change in each reaction? Explain your answer. – 7560
• Plan an investigation to show the effect of light from one direction on the growth of plant seedlings. Include details of any controls needed. You may use some of the equipment shown in Figure 1 and any other laboratory apparatus. – 7064
• Plants need other mineral ions. • Potassium ions are needed for healthy root growth. • Phosphate ions are needed for healthy flowers and fruits. The gardener makes his own garden compost. The percentage (%) of minerals in his compost was compared with two fertilisers he could buy. The data are shown in the table below. The gardener buys Fertiliser S. Explain why he chose Fertiliser S.- 7032
• Plastic and glass can be used to make milk bottles. The figure below shows the percentage of milk bottles made from glass between 1975 and 2010. The table below gives information about milk bottles. Evaluate the production and use of bottles made from soda-lime glass and those made from HD poly(ethene). Use the information given and your knowledge and understanding to justify your choice of material for milk bottles. – 6192
• Polyesters are made by a different method of polymerisation. The equation for the reaction to produce a polyester can be represented as: Compare the polymerisation reaction used to produce poly(ethene) with the polymerisation reaction used to produce a polyester. – 6164
• Polymer fibres are used to make firefighter uniforms. The table below shows some properties of two polymer fibres.Evaluate the suitability of poly(propene) and polyester for firefighter uniforms – 6162
• Potassium chloride is a mineral found in many foods. A student wants to make a salt called potassium chloride, KCl, by neutralisation of an acid by an alkali. Describe how to make a pure, dry sample of potassium chloride in a laboratory by neutralisation. – 7559
• Propane burns to form carbon dioxide and water. The equation for the reaction is: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) 3.60 dm3 carbon dioxide is produced when a sample of propane is burned in 7.25 dm3 oxygen. Calculate the volume of unreacted oxygen. Give your answer in cm3- 6182
• Propane burns to form carbon dioxide and water. The equation for the reaction is: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) 3.60 dm3 carbon dioxide is produced when a sample of propane is burned in 7.25 dm3 oxygen. Calculate the volume of unreacted oxygen. Give your answer in cm3 – 6156
• Propane burns to form carbon dioxide and water. The equation for the reaction is: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l) 3.60 dm3 carbon dioxide is produced when a sample of propane is burned in 7.25 dm3 oxygen. Calculate the volume of unreacted oxygen. Give your answer in cm3- 6114
• Pure metals are often converted into more useful alloys. For example, aluminium is converted into an alloy used in aircraft, iron is converted into an alloy used in cutlery and gold alloys are used in jewellery. These processes of alloying change the structures of the metals. Some properties of pure aluminium, iron and gold are shown in Figure.Explain how alloying changes these pure metals to make the alloys more suitable for the given uses – 9046
• Pure metals can be made more useful by converting them into alloys or by electroplating them. Explain what alloying and electroplating are and how they can make metals more useful – 9047
• Radio waves and gamma radiation are at opposite ends of the electromagnetic spectrum. Compare how these two electromagnetic radiations are produced – 8014 .
• Radio waves and gamma radiation are at opposite ends of the electromagnetic spectrum. Compare how these two electromagnetic radiations are produced – 8019
• Radioactive waste from nuclear power stations is a man-made source of background radiation.(c) Nuclear fission releases energy. Describe the process of nuclear fission inside a nuclear reactor. – 6042
• Ragwort is a weed that grows on farmland. Ragwort is poisonous to horses. Plan an investigation to estimate the size of a population of ragwort growing in a rectangular field on a farm. – 7095
• Red blood cells are specialised animal cells. Compare the structure of a red blood cell with the structure of a plant cell. – 7005
• Scientist 1 wants to identify the type of radiation emitted by isotope A. This is a list of equipment Scientist 1 has in his laboratory: • radiation detector • piece of thick lead • piece of cardboard • piece of aluminium. Describe how Scientist 1 does the experiment and explain how they can work out the type of radiation emitted. You may include a diagram in your answer – 7527
• Scientists are very concerned about the changes in concentration of carbon dioxide in the Earth’s atmosphere. The graph below shows the concentration of carbon dioxide in the atmosphere between 1988 and 2014. Describe two patterns shown in the graph above. – 7087
• Scientists are very concerned about the changes in concentration of carbon dioxide in the Earth’s atmosphere. The graph below shows the concentration of carbon dioxide in the atmosphere between 1988 and 2014. The trend shown in the graph above may continue for many years. Explain what effect the changing concentration of carbon dioxide in the atmosphere could have on living organism – 7088
• Scientists believe that ancestors of the modern Island Fox first colonised what is now Santa Cruz Island during the last Ice Age, approximately 16000 years ago. At that time, lowered sea levels made the three northernmost islands into a single island and the distance between this island and the mainland was reduced to about 8 km. A species of fox, called the Island Fox, lives on each of the six islands shown in Figure 1. Figure 2 shows an Island Fox. How could the Island Fox have developed into a completely different species from the mainland Grey Fox? – 7080
• Scientists can treat the patient’s tumour by replacing the trachea with a plastic trachea. The plastic trachea has a layer of the patient’s own stem cells covering it. Figure 2 shows the procedure. Stem cells can also be obtained from human embryos. Evaluate the use of stem cells from a patient’s own bone marrow instead of stem cells from an embryo Give a conclusion to your answer. – 7003
• Scientists have developed an artificial pancreas to treat type 1 diabetes. The diagram below shows how an artificial pancreas works. A woman with type 1 diabetes has an artificial pancreas. The woman eats a meal high in sugar. The meal causes her blood glucose level to rise. Use information from the diagram above to describe what happens to bring the blood glucose level of the woman back to normal. – 7056
• Scientists have found that great tits living now have longer beaks than great tits living 50 years ago. Genetic analysis shows changes in the sequence of the bird’s DNA. Scientists think that great tits living now have longer beaks because of the increased use of bird feeders during the last 50 years. Explain how natural selection could have caused an increase in beak length because of the use of bird feeders – 10025
• Scientists investigate antibiotic pollution in two different lakes. They collect samples of water from the two lakes. The scientists then use aseptic techniques to investigate how resistant the bacteria in the water are to antibiotics. Fig. 22.2 shows the apparatus they use. Describe how the scientists could use this apparatus to measure how resistant the bacteria are to antibiotics. – 7625
• Smoking is a lifestyle factor that can cause many diseases. Figure 15 shows the trends in smoking between 1960 and 2010 for men and women.Explain how the changes in the trends for smoking may affect the occurrence of cardiovascular disease – 10030
• Sodium chloride is an ionic compound, containing sodium ions, Na+ , and chloride ions, Cl– . The figure shows the electronic configuration of sodium and chlorine.Explain how sodium and chlorine atoms form the ions in sodium chloride and how the ions are arranged in the solid sodium chloride – 9007
• Sodium hydroxide reacts with hydrochloric acid. The diagram shows apparatus that can be used to find the volume of sodium hydroxide reacting with 25.0 cm3 hydrochloric acid Describe a method to find the exact volume of sodium hydroxide that reacts with 25.0 cm3 of hydrochloric acid. – 6142
• Sodium reacts with oxygen to produce the ionic compound sodium oxide. Oxygen is a Group 6 element. Draw a dot and cross diagram to show what happens when atoms of sodium and oxygen react to produce sodium oxide- 6092
• Solid lead reacts with nitric acid, HNO3. Lead nitrate, Pb(NO3)2, nitrogen oxide, NO, and water are made. How many moles of lead nitrate would be produced if 20.7 g of lead reacts with nitric acid? Give your answer to 2 significant figures. – 7558
• Soluble salts are formed by reacting metal oxides with acids. Describe a method to make pure, dry crystals of magnesium sulfate from a metal oxide and a dilute acid – 6012
• Some crop plants have been genetically modified to be resistant to insect pests. Explain the advantages and disadvantages of producing genetically modified crop plants – 10029
• Some painkillers prevent neurotransmitters binding to receptors in a synapse. Explain how a signal is transmitted at a synapse and how the painkillers reduce the pain felt by the person – 10011
• Some people have kidney failure. Doctors may treat patients with kidney failure by either: • dialysis • a kidney transplant.  Explain two biological reasons why most doctors think that a kidney transplant is a better method of treatment than dialysis. Do not refer to cost or convenience. – 7048
• Some properties of three substances are given as A, B and C. Deduce, using the information given the structure and bonding of substances A, B and C, explaining their properties in terms of their structure and bonding.
• Some properties of three substances, A, B and C are given. Deduce, using the information the structure and bonding of substances A, B and C, explaining their properties in terms of their structure and bonding – 9006
• Some sexually transmitted infections (STIs) can be diagnosed by testing urine samples. These tests use monoclonal antibodies that bind to an antigen on the pathogen. Describe how a monoclonal antibody can be developed and used to detect an STI using a urine sample – 10032
• Some students investigated the electrolysis of copper nitrate solution using inert electrodes. Figure 1 shows the apparatus The students investigated how the mass of copper produced at the negative electrode varied with Suggest how the students could find the total mass of copper produced.- 6124
• Some students investigated the size of a population of dandelion plants in a field. The diagram below shows the field. The students: • placed a 1 m × 1 m square quadrat at 10 random positions in the field • counted the number of dandelion plants in each quadrat. The table below shows the students’ results. Estimate the total number of dandelion plants in the field. Calculate your answer using information from the diagram and the table above. Give your answer in standard form. Total number of dandelion plants – 7083
• Some students investigated the size of a population of dandelion plants in a field. The diagram below shows the field. The students: • placed a 1 m × 1 m square quadrat at 10 random positions in the field • counted the number of dandelion plants in each quadrat. These quadrats contained low numbers of dandelion plants. The students made the hypothesis: ‘Light intensity affects the number of dandelion plants that grow in an area.’ Plan an investigation to test this hypothesis. – 7084
• Some surfboards are made from wood. The following table contains information about the materials in an addition polymer surfboard and a wooden surfboard. Suggest two advantages and two disadvantages of using addition polymers rather than wood to make surfboards. – 6188
• Some types of cancer can cause the numbers of blood components in a person’s body to fall to a dangerously low level. A person with one of these types of cancer may experience symptoms such as: • tiredness • frequent infections • bleeding that will not stop after the skin is cut. Explain how a very low number of blood components in the body can cause these symptoms. – 7017
• Sonar is an example of a use of ultrasound, it shows the depth of the sea, measured using sonar, at different distances from the shore. A technician on a boat uses sonar pulses to measure the depth of the sea when the boat is 120 m from the shore. Calculate the total time of travel for the sonar pulse used to make this measurement. The speed of the sonar pulse in seawater is 1600 m/s – 8007
• Starch is a nutrient in food. Starch is a source of energy. The diagram shows equipment that can be used to measure the energy content of different foods. – 10004
• Student C takes 0.5 minutes to push the trolley. How much power do they use? Show your working. – 7511
• student completes an experiment to find the specific heat capacity of a metal. The value obtained from the experiment is much higher than expected. Suggest two reasons how this could have occurred and suggest two improvements to the experimental procedure. – 7503
• Students investigated the size of the population of Daphnia in the pond. This is the method used. 1. Collect 1 dm3 of pond water from near the edge of the pond. 2. Pour the water through a fine net. 3. Count the number of Daphnia caught in the net. 4. Repeat steps 1–3 four more times. The pond was a rectangular shape, measuring: • length = 2.5 metres • width = 1.5 metres • depth = 0.5 metres. Calculate the estimated number of Daphnia in the pond. Use your answer from part (d). Give your answer in standard form. Number of Daphnia in the pond – 7091
• Syndrome H is an inherited condition. People with syndrome H do not produce the enzyme IDUA. Figure 3 shows part of the gene coding for the enzyme IDUA. Strand K shows a mutation in the DNA which has caused syndrome H. The enzyme IDUA helps to break down a carbohydrate in the human body. The enzyme IDUA produced from Strand K will not work. Explain how the mutation could cause the enzyme not to work – 7073
• The actual value for the specific heat capacity of water is 4200 J/kg °C. Write down two problems with this experiment and suggest how they could be solved. Use the diagram and results table to help you. – 7504
• The allele for blood group A and the allele for blood group B are codominant. Gregor Mendel investigated the inheritance of alleles using flowering plants.He showed that the allele for red flowers (IR ) is codominant with the allele for white flowers (IW). A heterozygous plant produces pink flowers. Explain the outcome if two plants that produce pink flowers are crossed. You should complete the Punnett square as part of your answer – 10014
• The Big Bang theory gives an explanation for the origin of the Universe. Explain how evidence supports the ideas that the Universe is expanding and the Universe began at a single point – 8026
• The book ‘On the Origin of Species’ was published in 1859.This book describes the theory of evolution. One chapter of this book discusses pentadactyl limbs.Another chapter of the book discusses how the shape of bird beaks has evolved on different islands. Two species of finch evolved from a common ancestor that had a similar shaped beak to species B. Beak shape is related to the food that the finches eat. Describe how the thinner beak of species A is a result of evolution – 10020
• The brown body colour of a drosophila fruit fly is dominant to black body colour and is not sex-linked.Explain how Gregor Mendel could have used a brown drosophila fruit fly and a black drosophila fruit fly to show that brown body colour is dominant to black body colour – 10015
• The chart below shows a cell cycle. Describe what happens during each stage of the cell cycle. – 7009
• The combined pill is a contraceptive that contains progesterone and oestrogen. The ‘mini-pill’: • is a contraceptive that only contains the progesterone hormone • has to be taken at the same time each day to prevent pregnancy. The success rate of the mini-pill in preventing pregnancy is lower than that of the combined pill. Explain why missing a dose of the mini-pill would reduce the success rate of the mini-pill. – 7055
• The concentration of dilute sulfuric acid can be determined by titration with sodium hydroxide solution of known concentration. 25.00 cm3 of dilute sulfuric acid was measured out using a pipette and transferred to a conical flask. A few drops of methyl orange indicator were added to the acid in the conical flask. Sodium hydroxide solution was added to the acid from a burette until the indicator changed colour. The titration was repeated until two concordant results were obtained. The accurate result was the average of the two concordant results. Explain two details that could be added to this practical method to ensure an accurate result is obtained – 9037
• The concentration of mineral ions in the soil is lower than in root hair cells. Root hair cells take up mineral ions from the soil. Root hair cells contain mitochondria. Explain why root hair cells contain mitochondria. – 7010
• The concentration of mineral ions in the soil is lower than in root hair cells. Root hair cells take up mineral ions from the soil. Root hair cells contain mitochondria. Explain why root hair cells contain mitochondria. – 7021
• The diagram below shows a diagram of the lock. The door unlocks when the switch is closed. When the door unlocks, a force of 2.88 N is applied to the spring. The spring extends by 1.50 cm. Calculate the spring constant of the spring. – 6075
• The diagram below shows an unusually shaped container. The container has four vertical tubes of different shape and size A person swims from a depth of 0.50 m to a depth of 1.70 m below the surface of the sea. density of the sea water = 1030 kg/m3 gravitational field strength = 9.8 N/kg Calculate the increase in pressure on the swimmer. Give the unit. Use an equation from the Physics Equation Sheet. – 6061
• The diagram below shows changes in the foot bones of four ancestors of modern horses over the past 50 million years. The changes in the arrangement of the foot bones of horses support Darwin’s theory of evolution by natural selection. Explain how the arrangement of the foot bones of Eohippus could have evolved into the arrangement of the foot bones of Equus. – 7079
• The diagram below shows part of a DNA molecule. Describe the structure of a nucleotide. – 7069
• The diagram below shows part of a DNA molecule. The length of a DNA double helix increases by 0.34 nm for every pair of nucleotides. The total number of nucleotides in a human body cell is 1.2 × 1010. Calculate the total length of double helix in a human body cell. Give your answer in metres. Use information from the diagram . – 6024
• The diagram below shows part of a DNA molecule. The length of a DNA double helix increases by 0.34 nm for every pair of nucleotides. The total number of nucleotides in a human body cell is 1.2 × 1010. Calculate the total length of double helix in a human body cell. Give your answer in metres. Use information from the diagram. – 7070
• The diagram below shows part of a mains electricity lighting circuit in a house. A fault in the switch caused a householder to receive a mild electric shock before a safety device switched the circuit off. The mean power transfer to the person was 5.75 W. The potential difference across the person was 230 V. Calculate the resistance of the person.
• The diagram below shows part of a mains electricity lighting circuit in a house. A fault in the switch caused a householder to receive a mild electric shock before a safety device switched the circuit off. The mean power transfer to the person was 5.75 W. The potential difference across the person was 230 V. Calculate the resistance of the person. – 6002
• The diagram below shows two guard cells surrounding a closed stoma and two guard cells surrounding an open stoma. When light intensity is high potassium ionsare moved into the guard cells. Describe how the movement of potassium ions into the guard cells causes the stoma to open. – 7020
• The diagram of light entering an eye of someone who cannot see distant objects clearly. Explain why this person cannot see distant objects clearly and how the problem can be corrected – 10009
• The diagram shows a greenhouse. A greenhouse frame can be made from wood or aluminium. Table 1 gives some information about wood and aluminium. Evaluate the use of each material for making greenhouse frames. – 6191
• The diagram shows four groups of stars. The surface temperature and relative luminosity determine which group a star is in. A star with a relative luminosity of 1 emits the same amount of energy every second as the Sun. – 6071
• The diagram shows four groups of stars. The surface temperature and relative luminosity determine which group a star is in. A star with a relative luminosity of 1 emits the same amount of energy every second as the Sun. At different points in their lifecycle stars change from one group to another. Describe what will happen to the Sun between it leaving the main sequence group and becoming a white dwarf. Use information from the diagram. – 6084
• The diagram shows how some of the energy released by the Sun is converted into electrical energy.A student boils some water using energy which came from the Sun.Using the information in the diagram, describe the energy transfers involved inproducing the electrical energy he used. – T
• The diagram shows one of the valves that can be made leaky by rheumatic fever. People who have this leaky valve often have these symptoms: o they get out of breath easily o they do not seem to have much energy and feel tired. Write about the job of this valve and how damage to it may cause these symptoms. – 7609
• The diagram shows one of the valves that can be made leaky by rheumatic fever. People who have this leaky valve often have these symptoms: o they get out of breath easily o they do not seem to have much energy and feel tired. Write about the job of this valve and how damage to it may cause these symptoms. – 7626
• The diagram shows the flow of biomass through an agricultural food chain. The plants grown for cattle food often have their leaves eaten by insects. Scientists have produced genetically modified (GM) plants that make insecticide in their leaves. Explain why these GM plants would make more biomass available to humans. In your answer use the diagram of the agricultural food chain and ideas about photosynthesis. – 7603
• The diagram shows the flow of biomass through an agricultural food chain. The plants grown for cattle food often have their leaves eaten by insects. Scientists have produced genetically modified (GM) plants that make insecticide in their leaves. Explain why these GM plants would make more biomass available to humans. In your answer use the diagram of the agricultural food chain and ideas about photosynthesis. – 7623
• The Earth contains a crust, mantle and core as shown in Fig. 22.1. Table 22.1 gives some data about seismic waves and the Earth. Describe what information the data in Table 22.1 gives about the structure of the Earth. In your answer you should explain any trends in the data in Table 22.1. – 7523
• The Earth’s early atmosphere was different to Earth’s atmosphere today. Scientists think that the Earth’s early atmosphere was like the atmosphere found on Venus today. The table below shows the amounts of carbon dioxide and oxygen in the atmospheres of Venus and Earth today. – 6017
• The Earth’s early atmosphere was different to Earth’s atmosphere today. Scientists think that the Earth’s early atmosphere was like the atmosphere found on Venus today.The table below shows the amounts of carbon dioxide and oxygen in the atmospheres of Venus and Earth today. The percentages of carbon dioxide and oxygen have changed from Earth’s early atmosphere to Earth’s atmosphere today. Explain the processes that led to these changes – 6183
• The element lithium gives a moderate reaction with cold water, releasing hydrogen and forming a solution of lithium hydroxide. Describe how sodium is similar to and how it is different from lithium in its chemical reaction with cold water. Explain any similarity or difference in terms of their atomic structure.- 6028
• The energy needed for a car powered by a hydrogen fuel cell to travel 100 km is 58 megajoules (MJ). The energy released when 1 mole of hydrogen gas reacts with oxygen is 290 kJ The volume of 1 mole of a gas at room temperature and pressure is 24 dm3 Calculate the volume of hydrogen gas at room temperature and pressure needed for the car to travel 100 km – 6112
• The equation for the reaction between potassium hydroxide solution and dilute hydrochloric acid is KOH + HCl → KCl + H2O Calculate the atom economy for the production of potassium chloride from potassium hydroxide and hydrochloric acid. (relative formula masses: KOH = 56.0, HCl = 36.5, KCl = 74.5, H2O = 18.0) Give your answer to one decimal place. – 9018
• The equation for this equilibrium reaction is C2H6—> C2H6 + H2. The forward reaction takes in heat energy and is endothermic. A manufacturer produces large quantities of propene using this equilibrium reaction. Suggest, with explanations, suitable conditions that the manufacturer could use to maximise the yield and rate of production of propene from propane – 9032
• The eyes of some birds contain cells that detect ultraviolet (UV) light. UV light is reflected by some fruits and the urine of small mammals. Explain how birds that detect UV light have evolved from birds that could not detect UV light. – 7059
• The figure below shows a Bunsen burner heating some water in a beaker. Eventually the water changes into steam. A student measured the mass of boiling water that was turned into steam in five minutes. Explain how the student could use this information to estimate the power output of the Bunsen burner in watts. – 6041
• The figure below shows a house with a solar power system. The solar cells generate electricity. When the electricity generated by the solar cells is not needed, the energy is stored in a large battery. – 6048
• The figure below shows a toy car in different positions on a racing track. The car is released from rest at position A and accelerates due to gravity down the track to position B. mass of toy car = 0.040 kg vertical height between position A and position B = 90 cm gravitational field strength = 9.8 N/kg Calculate the maximum possible speed of the toy car when it reaches position B. – 6049
• The figure below shows six test tubes a student set up to investigate the rusting of iron. This is the method used for each test tube. 1. Measure the mass of the nail using a balance. 2. Leave the nail in the test tube for 6 days. 3. Measure the mass of the nail after 6 days. Calculate the difference in percentage increase in mass after 6 days of the nail in test tube 1 and the nail in test tube 5. Give your answer to three significant figures. – 6194
• The figure below shows six test tubes a student set up to investigate the rusting of iron. This is the method used for each test tube. 1. Measure the mass of the nail using a balance. 2. Leave the nail in the test tube for 6 days. 3. Measure the mass of the nail after 6 days.Use the results of the student’s investigations to draw conclusions about the factors affecting the rusting of iron. Include an evaluation of the effectiveness of different coatings at preventing the rusting of iron.  – 6195
• The figure below shows the parts of a moving-coil loudspeaker. A coil of wire is positioned in the gap between the north and south poles of the cylindrical magnet. Explain how the loudspeaker converts current in an electrical circuit to a sound wave. – 6082
• The figure below shows the parts of a moving-coil loudspeaker. A coil of wire is positioned in the gap between the north and south poles of the cylindrical magnet. Explain how the loudspeaker converts current in an electrical circuit to a sound wave. – 6072
• The figure shows cells undergoing mitosis. Describe how the stages of mitosis result in the formation of two diploid cells – 10006
• The Figure shows two objects, Q and R, before and after they collide. The arrows show the direction of movement of the objects. The arrows are not to scale. Explain how momentum is conserved in the collision. Use Newton’s third law and Newton’s second law in your answer. – 8002
• The following descriptions describe waves from different parts of the electromagnetic spectrum. Complete each description by adding the name of the wave. Use the name of each wave only once. Each description refers to a different part of the electromagnetic spectrum – 8015.
• The following table and the figure show the scientists’ results. In the table and the figure some standard deviations of results overlap. • An overlap of standard deviations shows the difference between the means is not significant. • No overlap of standard deviations shows a significant difference between the means. A student looked at the scientists’ method and the results in the table and figure above. The student stated: ‘Metformin works better when used with other drugs.’ Evaluate the student’s statement.Empty Page for ASKNAt – 7050
• The formula of aluminium sulfate is Al2(SO4)3. Calculate the total number of atoms that combine to form 5.13 g of aluminium sulfate. (relative atomic masses: O = 16.0, Al = 27.0, S = 32.0 Avogadro number = 6.02 × 1023) – 9003
• The graph below shows the distance-time graph for the first 30 seconds of the car’s motion. A different car accelerated from 0.12 m/s to 0.52 m/s. The acceleration of the car was 0.040 m/s2. The work done to accelerate the car was 0.48 J. Calculate the resultant force needed to accelerate the car. – 6066
• The graph below shows the distance-time graph for the first 30 seconds of the car’s motion. Determine the speed of the car 20 seconds after it started to move. – 6065
• The graph below shows the results. Describe a method the student could have used to obtain the results shown in the graph above. – 6063
• The graph in Fig. 19.1 shows how displacement of an ultrasound wave varies with distance. Use the graph in Fig. 19.1 to determine the wavelength of an ultrasound wave. The speed of ultrasound waves in (i) is 4500 m / s. Calculate the frequency of the ultrasound wave in Fig. 19.1. Use the equation: wave speed = frequency × wavelength Give your answer in standard form and to 2 significant figures. – 7522
• The graph shows how the braking distance, d, of a car depends on the velocity, v, of the car when the brakes are first applied. An equation relating braking distance, d, to velocity, v, is d = v^2/ c. where C is a constant. Use the equation and data from the graph in Figure 1 to calculate a value for C. Give a unit for C – 8003.
• The graph shows the levels of erythromycin in the blood when given using this capsule and in a normal tablet. Explain the shape of the two graphs and why it is better to give erythromycin in capsules. – 7606
• The graph shows the levels of erythromycin in the blood when given using this capsule and in a normal tablet. Explain the shape of the two graphs and why it is better to give erythromycin in capsules. – 7627
• The growth of daisy plants on a lawn is affected by biotic factors and by abiotic factors. The figure below shows a plan of a garden. A student estimates the number of daisy plants growing on the lawn. The student places a quadrat at 10 different positions on the lawn. The quadrat measures 50 cm × 50 cm. The student counts the number of daisy plants in each quadrat. The mean number of daisy plants in each quadrat is 6. Calculate the number of daisy plants on the lawn. Give your answer to 3 significant figures. Number of daisy plants on the lawn – 7081
• The higher the concentration of a sample of dilute sulfuric acid, the greater the volume of sodium hydroxide needed to neutralise the acid. The student tested two samples of dilute sulfuric acid, P and Q. Describe how the student could use titrations to find which sample, P or Q, is more concentrated. – 6138
• The human eye can focus on objects at different distances. Figure 1 shows how a clear image of a distant object is formed in a person’s eye. Explain how the person’s eye could adjust to form a clear image of a nearer object. – 7060
• The hydrogen used in a hydrogen-oxygen fuel cell can be produced from methanol, CH3OH. In this reaction the forward reaction is endothermic and heat energy is taken in from the surroundings. The conditions used for this reaction are a nickel catalyst and a temperature of 220 °C . Explain, in terms of their effects on the rate of attainment of equilibrium and the equilibrium yield of hydrogen, why the reaction is carried out using a catalyst at 220 °C rather than without a catalyst at a lower temperature – 9035
• The hydrogen used in a hydrogen-oxygen fuel cell can be produced from methanol, CH3OH.In this reaction the forward reaction is endothermic and heat energy is taken in from the surroundings. The conditions used for this reaction are a nickel catalyst , a temperature of 220 °C .Explain, in terms of their effects on the rate of attainment of equilibrium and the equilibrium yield of hydrogen, why the reaction is carried out using a catalyst at 220 °C rather than without a catalyst at a lower temperature -9028
• The image below shows a student playing with a remote-controlled car. Explain why the car has a maximum speed.- 6067
• The image below shows a student playing with a remote-controlled car. The remote control transmits radio waves to the car aerial. The transmitted radio waves have a frequency of 320 MHz. speed of radio waves = 3.0 × 108 m/s Calculate the wavelength of the radio waves. Give the unit. – 6064
• The image below shows two ice hockey players moving towards each other. They collide and then move off together. – 6056
• The image is a semicircular glass block. Describe how a student could use the semicircular glass block and other apparatus to determine the critical angle for a glass-air boundary – 8010
• The images shows the three stone tools found in different layers of rock. Explain how information from these images provides evidence for human evolution – 10021
• The industrial production of sulfuric acid involves several steps. One of these steps is the reaction of sulfur dioxide, SO2, with oxygen to form sulfur trioxide, SO3. The reaction to produce sulfur trioxide reaches an equilibrium. A manufacturer considered two sets of conditions, A and B, for this reaction. In each case sulfur dioxide is mixed with excess oxygen. The manufacturer changed the temperature and the pressure and only used a catalyst in B and also r chooses set of conditions B rather than set of conditions A. Explain, by considering the effect of changing the conditions on the rate of attainment of equilibrium and on the equilibrium yield of sulfur trioxide, why the manufacturer chooses the set of conditions B rather than the set of conditions A – 9030
• The industrial production of sulfuric acid involves several steps. One of these steps is the reaction of sulfur dioxide, SO2, with oxygen to form sulfur trioxide, SO3. The reaction to produce sulfur trioxide reaches an equilibrium. The forward reaction is exothermic. The rate of attainment of equilibrium and the equilibrium yield of sulfur trioxide are affected by pressure and temperature. A manufacturer considered two sets of conditions, A and B, for this reaction. In each case sulfur dioxide is mixed with excess oxygen. The manufacturer changed the temperature and the pressure and only used a catalyst in B. The sets of conditions A and B are shown in Figure 7. – 9023
• The information below gives some features of two types of treatment for kidney disease. Evaluate the use of a kidney transplant instead of dialysis treatment for kidney disease. – 7051
• The man has red hair. His sister has brown hair. Both of their parents have brown hair. Brown hair is caused by the dominant allele, B. Red hair is caused by a recessive allele, b. Complete the genetic diagram below to show how the man’s parents were able to have some children with red hair and some with brown hair. – 7075
• The mean number of daisy plants in each quadrat is 6. Calculate the number of daisy plants on the lawn. Give your answer to 3 significant figures. – 7033
• The melting points of two substances, A and B, and the abilities of the substances to conduct an electric current when solid and when molten.One of the substances has an ionic structure and one has a simple molecular, covalent structure. Explain, in terms of bonding and the forces between the particles, the relative melting points and abilities to conduct the electric current of substances A and B – 9008
• The method used to make lead sulfate is to pour 100 cm3 lead nitrate solution into a beaker , add drops of sodium sulfate solution until a precipitate is seen , allow the precipitate to settle to the bottom of the beaker , pour off the liquid and use a spatula to transfer the solid lead sulfate onto a filter paper .Explain two ways of improving this experimental method to increase the amount and quality of lead sulfate obtained from the same volume of lead nitrate solution – 9045
• The method used to make the lead sulfate is: pour 100 cm3 lead nitrate solution into a beaker, add drops of sodium sulfate solution until a precipitate is seen , allow the precipitate to settle to the bottom of the beaker, pour off the liquid and use a spatula to transfer the solid lead sulfate onto a filter paper. Explain two ways of improving this experimental method in order to increase the amount and quality of lead sulfate that could be obtained from 100 cm3 of lead nitrate solution – 9039
• The model of the atom changed as new evidence was discovered. The plum pudding model suggested that the atom was a ball of positive charge with electrons embedded in it. Evidence from the alpha particle scattering experiment led to a change in the model of the atom from the plum pudding model.  – 6086
• The outer electrons in an atom of the Group 1 element potassium and in an atom of the Group 6 element sulfur. Potassium forms an ionic compound with sulfur. Describe what happens when two atoms of potassium react with one atom of sulfur. Give your answer in terms of electron transfer. Give the formulae of the ions formed.
• The overall equation for the electrolysis of aluminium oxide is: 2 Al2O3 → 4 Al + 3 O2 Calculate the mass of oxygen produced when 2000 kg of aluminium oxide is completely electrolysed. Relative atomic masses (Ar): O = 16 Al = 27 – 6126
• The overall equation for the electrolysis of aluminium oxide is: 2 Al2O3 → 4 Al + 3 O2 Calculate the mass of oxygen produced when 2000 kg of aluminium oxide is completely electrolysed. Relative atomic masses (Ar): O = 16 Al = 27 – 6113
• The photograph below shows a balloon filled with helium gas. The temperature of the helium in the balloon was increased. The mass and volume of helium in the balloon remained constant. Explain why the pressure exerted by the helium inside the balloon would increase. – 6039
• The photograph below shows a balloon filled with helium gas.The pressure of the helium in the balloon is 100 000 Pa. The volume of the balloon is 0.030 m3 . The balloon is compressed at a constant temperature causing the volume to decrease to 0.025 m3 . No helium leaves the balloon. Calculate the new pressure in the balloon. – 6038
• The photograph below shows a coffee machine. The coffee machine uses an electric element to heat water. The coffee machine heats water from 20 °C to 90 °C. The power output of the coffee machine is 2.53 kW. The specific heat capacity of water is 4200 J/kg °C. Calculate the mass of water that the coffee machine can heat in 14 seconds. – 6032
• The photograph below shows a coffee machine. The coffee machine uses an electric element to heat water.(c) The coffee machine heats water from 20 °C to 90 °C. The power output of the coffee machine is 2.53 kW. The specific heat capacity of water is 4200 J/kg °C. Calculate the mass of water that the coffee machine can heat in 14 seconds.- 6052
• The photograph below shows a theme park ride called AquaShute. Riders of the AquaShute sit on a sled and move down a slide (c)At the bottom of the slide, all riders and their sleds have approximately the same speed. Explain why.- 6051
• The photograph below shows a theme park ride called AquaShute. Riders of the AquaShute sit on a sled and move down a slide. The decrease in gravitational potential energy of one rider on the slide was 8.33 kJ. The rider moved through a vertical height of 17.0 m. gravitational field strength = 9.8 N/kg Calculate the mass of the rider. – 6050
• The plum pudding model of the atom was replaced by the nuclear model. The nuclear model was developed after the alpha particle scattering experiment. Compare the plum pudding model with the nuclear model of the atom. – 6088
• The pure metals aluminium, copper and gold and the alloys brass and magnalium are used to make many useful articles.The way in which these metals and alloys are used is related to their properties, such as their density, electrical conductivity, resistance to corrosion and strength. State some uses of aluminium, copper, gold, brass and magnalium and explain how each use is related to their properties – 9048
• The rainforest contains: • 750 species of trees • 400 species of birds • 150 species of butterflies • many other species of plants and animals. Explain how the pattern of cutting down trees shown in Figure 2 stops the biodiversity of the rainforest being reduced. – 7066
• The reaction between nitrogen and hydrogen is exothermic. If nitrogen and hydrogen were reacted at 150 atm pressure and 300 °C, without a catalyst, some ammonia would be formed. In the Haber process a pressure of 150 atm and a temperature of 450 °C are used, in the presence of an iron catalyst. Explain why the conditions used in the Haber process are better than the first set of conditions for the manufacture of ammonia – 9026
• The reaction between nitrogen and hydrogen is exothermic. If nitrogen and hydrogen were reacted at 150 atm pressure and 300 °C, without a catalyst, some ammonia would be formed. In the Haber process a pressure of 150 atm and a temperature of 450 °C are used, in the presence of an iron catalyst.Explain why the conditions used in the Haber process are better than the first set of conditions for the manufacture of ammonia – 9033
• The reaction is carried out at a pressure of 200 atmospheres. Explain what effect a pressure higher than 200 atmospheres would have on the rate of attainment of equilibrium and on the equilibrium yield of ammonia. – 9025
• The resultant force of the towbar on the trailer has a horizontal component and a vertical component. horizontal force = 200 N vertical force = 75 N  Determine the magnitude and direction of the resultant force of the towbar on the trailer by drawing a vector diagram. – 6055
• The rock pocket mouse is a small grey coloured mouse that lives in Mexico. These mice are the main food for owls. Rattlesnakes also feed on these mice. The mice get most of their food from grass plants. Scientists want to construct a pyramid of biomass for this food web. They first need to estimate how many organisms there are in the area. They decide to do this using sampling. * To estimate grass cover and the number of animals, they use a quadrat. Why do scientists use sampling when studying the organisms living in a habitat? Identify the limitations of this method and potential improvements that could be made to ensure that the estimated population size of plants and animals closely matches the actual value. – 7629
• The rock pocket mouse is a small grey coloured mouse that lives in Mexico. These mice are the main food for owls. Rattlesnakes also feed on these mice.In most areas of Mexico the ground is covered in grey rocks. In one area the ground is covered with black rocks. The black rocks were formed about 1000 years ago when a volcano erupted. Scientists make two observations: • very occasionally a black mouse is born to grey parents due to a mutation • black mice are well camouflaged. Use these observations to explain why most of the mice in this area are black and not the usual grey. – 7621
• The scientists want to produce a type of cattle that makes large volumes of low-fat milk. The scientists will selectively breed some of the animals shown in Figure 2. Describe how the scientists would do this. – 7072
• The simplified diagram to show radio waves from a transmitter moving upwards, then meeting a boundary between lower and upper layers of the atmosphere. Explain what happens to the radio waves after they meet the boundary between the lower and upper layers as shown in Figure. Your explanation should refer to changes in direction and speed of the waves – 8008.
• The simplified diagram to show radio waves from a transmitter moving upwards, then meeting a boundary between lower and upper layers of the atmosphere.Explain what happens to the radio waves after they meet the boundary between the lower and upper layers as shown in Figure 6.Your explanation should refer to changes in direction and speed of the waves – 8013.
• The spring constant of a different spring is 40 N / m. Calculate the energy stored in the spring when it is stretched 0.20 m. Use an equation from the data sheet to help you. – 7508
• The student decides to build a model transformer. The transformer is a step-up transformer which doubles the input voltage. Describe how they could build this step-up transformer in a science laboratory. – 7520
• The student found that 25.0 cm3 of the sodium hydroxide solution was neutralised by 15.00 cm3 of the 0.0480 mol/dm3 ethanedioic acid solution. The equation for the reaction is: H2C2O4 + 2 NaOH → Na2C2O4 + 2 H2O Calculate the concentration of the sodium hydroxide solution in mol/dm3 – 6137
• The student measures the time it takes for all the magnesium to react. This is the reaction time. The student does five experiments. This is the student’s prediction: “The smaller the volume of acid and the smaller the mass of magnesium, the shorter the reaction time.”  Look at the student’s results. Describe and explain whether the student’s results support his prediction. Include ideas about the reacting particle model in your answer. – 7564
• The student placed the agar plate in an incubator at 25 °C for 48 hours. Figure 2 shows the agar plate after 48 hours. Calculate the area where no bacteria were growing for antibiotic C.  Use π = 3.14 Give the unit.- 7006
• The student repeated the investigation. The student used solutions that had different concentrations from the first investigation. The student found that 15.5 cm3 of 0.500 mol/dm3 dilute sulfuric acid completely reacted with 25.0 cm3 of potassium hydroxide solution. The equation for the reaction is: 2 KOH + H2SO4 → K2SO4 + 2 H2O Calculate the concentration of the potassium hydroxide solution in mol/dm3 and in g/dm3 Relative atomic masses (Ar): H = 1 O = 16 K = 39 – 6120
• The student repeated the investigation. The student used solutions that had different concentrations from the first investigation. The student found that 15.5 cm3 of 0.500 mol/dm3 dilute sulfuric acid completely reacted with 25.0 cm3 of potassium hydroxide solution. The equation for the reaction is: – 6105
• The student takes readings of potential difference and current and records them in Table 17.1. There are two mistakes in the results table. Write down the two mistakes and suggest how they could be corrected. – 7517
• The student then set up the apparatus correctly. Figure 2 shows the student’s results. Determine the mean rate of reaction between 0 seconds and 60 seconds- 6169
• The student’s results are shown in the table. Describe and explain the trends shown in the student’s results. – 6167
• The table below gives some information about disposable cups. Compare the advantages and disadvantages of using coated paper and poly(styrene) to make disposable cups. Use the table above and your knowledge and understanding of life cycle assessments (LCAs). – 6163
• The table below gives some information about disposable cups. Compare the advantages and disadvantages of using coated paper and poly(styrene) to make disposable cups. Use the table above and your knowledge and understanding of life cycle assessments (LCAs). – 6189
• The table below shows data about different ways to power electric cars. Evaluate the use of hydrogen fuel cells compared with rechargeable lithium-ion batteries to power electric cars. Use the table above and your own knowledge. – 6166
• The table below shows the student’s results.The equation for the reaction is: 2 NaOH + H2SO4 ⟶ Na2SO4 + 2 H2O Calculate the concentration of the sulfuric acid in mol/dm3 Use only the student’s concordant results. Concordant results are those within 0.10 cm3 of each other. – 6121
• The table shows Emma’s results. Write a conclusion with an explanation about this experiment. Use data / calculations in your answer. – 7610
• The table shows the effectiveness of some different forms of contraception. Suggest explanations for the differences in the effectiveness of the methods of contraception and explain why the pill is a popular method. – 7613
• The table shows the results. One student started to draw a graph but did not finish. Complete the graph using the results in the table and draw a curve of best fit. – 7601
• The table shows the student’s results. The equation for the reaction is: C6H8O7 + 3 NaOH ⟶ C6H5O7Na3 + 3 H2O The concentration of the sodium hydroxide was 0.102 mol / dm3 Concordant results are those within 0.10 cm3 of each other. Calculate the concentration of the citric acid in mol / dm3 Use only the concordant results from the table in your calculation. You must show your working. – 6122
• The three-pin plug used to connect the kettle to the mains. A fault occurs in the kettle causing the live wire to touch the metal case of the kettle. Explain how the safety features of the plug operate when this fault occurs.
• The word equation for the reaction between copper carbonate and dilute sulfuric acid is Figure 12 shows a conical flask containing dilute sulfuric acid. Copper carbonate is added to the acid in the flask. The copper carbonate is added one spatula measure at a time until the reaction has finished. – 9016
• There are many types of rat snake in the world. The table below shows two types of rat snake. The different types of rat snake have evolved from similar ancestors. The rat snakes have evolved to to suit their environments. Explain how the Japanese rat snake evolved to be different from the Texas rat snake. – 7067
• There are several species of the camel family alive today. Scientists think these species evolved from a common ancestor that lived in North America about 45 million years ago (Mya). • where four modern species of the camel family live today • how the ancestors of these camels migrated from North America Explain how several different species of camel could have evolved from a common ancestor over 45 million years. – 7082
• There are two isotopes of element A. Information about the two isotopes is shown in the table below. Mass number of the isotope 6 7 Percentage abundance 92.5 7.5 Use the information in the table above above to calculate the relative atomic mass of element A. Give your answer to 2 decimal places. – 6089
• This is a graph showing the radiation emitted from samples of three different isotopes A, B and C.Two scientists discuss the isotopes in the graph. Two scientists discuss the isotopes in the graph. Do you agree with the views of scientist 1 and scientist 2? Use the graph and ideas about radioactivity and half-life to explain your answer. – 7526
• This question is about copper and alloys of copper. Solders are alloys used to join metals together. Some solders contain copper. Copper is extracted from low-grade ores by phyto mining. Describe how copper is extracted from low-grade ores by Phyto mining. – 6185
• This question is about light. Figure 11a shows refraction of light at a boundary between glass and air and Figure 11b shows total internal reflection of light at a boundary between glass and air. Explain refraction and total internal reflection – 8009.
• This question is about lithium carbonate. Lithium carbonate is used in medicines Lithium carbonate contains lithium ions and carbonate ions. A student tested the tablet for lithium ions and for carbonate ions. The student used: • a metal wire • dilute hydrochloric acid • limewater. Plan an investigation to show the presence of lithium ions and of carbonate ions in the tablet. You should include the results of the tests for the ions. – 6016
• This question is about lithium carbonate. Lithium carbonate is used in medicines. The figure shows a tablet containing lithium carbonate. Lithium carbonate contains lithium ions and carbonate ions. A student tested the tablet for lithium ions and for carbonate ions. The student used: • a metal wire • dilute hydrochloric acid • limewater. Plan an investigation to show the presence of lithium ions and of carbonate ions in the tablet. You should include the results of the tests for the ions. – 6176
• This question is about materials used to make food plates. Food plates are made from paper, polymers or ceramics. The table below shows information about plates of the same diameter made from each of these materials. Evaluate the use of these materials for making food plates. You should use features of life cycle assessments (LCAs). – 6187
• This question is about materials used to make food plates. Food plates are made from paper, polymers or ceramics. The table below shows information about plates of the same diameter made from each of these materials. Evaluate the use of these materials for making food plates. You should use features of life cycle assessments (LCAs).- 6193
• This question is about metal carbonates. A student investigated the reaction of copper carbonate with an acid. The student plotted the results on a graph. Determine the gradient of the line of best fit.You should calculate the values of the change in y and the change in x and calculate the gradient of the line of best fit – 6135
• This question is about metal compounds. Lithium reacts with chlorine to produce lithium chloride. When lithium atoms and chlorine atoms react to produce lithium chloride, lithium ions and chloride ions are formed. The diagram shows the electronic structures of the atoms and ions. The symbols o and x are used to represent electrons. – 6108
• This question is about methanol. In industry, methanol is produced by reacting carbon monoxide with hydrogen. The equation for the reaction is: A pressure of 100 atmospheres is used instead of atmospheric pressure. The higher pressure gives a greater yield of methanol and an increased rate of reaction. Explain why. – 6173
• This question is about paper chromatography. A food colouring contains a dye. Plan an investigation to determine the Rf value for the dye in this food colouring. Your plan should include the use of: • a beaker • a solvent • chromatography paper.- 6129
• This question is about properties of materials. Police bullet-resistant vests could be made from steel or Kevlar. The table shows some information about steel and Kevlar. Describe and explain two reasons why bullet-resistant vests are made from kevlar instead of steel. – 7567
• This question is about radioactivity.Exposing people to radioactive sources can be dangerous. Describe the dangers of exposure to radioactive sources and what can be done to protect hospital staff when they are working with radioactive sources – 8021
• This question is about reactions of ethanoic acid and the analysis of salts. Figure 1 shows the apparatus used to investigate the reaction of ethanoic acid with calcium carbonate. Describe a change that would be seen in each test tube. Give a reason for each change. Test tube 1 – 6161
• This question is about selective breeding. Cows are female and are used by farmers to produce milk. Bulls are male. Look at the details of different varieties of cows and bulls. A farmer wants to produce cows that produce a high yield of creamy milk. – 7622
• This question is about structure and bonding. The table below shows the structures of three compounds. Compare the structure and bonding of the three compounds: • carbon dioxide• magnesium oxide • silicon dioxide.- 6010
• This question is about the halogens. Table 1 shows the melting points and boiling points of some halogens.- 6093
• This question is about the nervous system. Describe the difference between the function of a receptor and the function of an effector. In your answer you should give one example of a receptor and one example of an effector. – 7063
• This question is about the structure of the atom. Complete the sentences. Choose answers from the box. Each word may be used once, more than once, or not at all. – 6087
• This question is about water. In the UK, potable (drinking) water is produced from different sources of fresh water. Explain how potable water is produced from fresh water. – 6186
• Three elements in Group 2 of the periodic table are beryllium (Be), magnesium (Mg) and calcium (Ca). Their mass numbers and proton numbers are shown below. The electronic structure is shown for beryllium and calcium.- 6029
• Titanium and iron are examples of transition metals. 2.24 g of iron combines with 0.96 g of oxygen to form an oxide of iron.Determine the formula of this oxide of iron and use it to complete the balanced equation. You must show your working – 9004
• Titanium is a transition metal. Titanium is extracted from titanium dioxide in a two-stage industrial process. Stage 1 TiO2 + 2 C + 2 Cl2 ⟶ TiCl4 + 2 CO Stage 2 TiCl4 + 4 Na ⟶ Ti + 4 NaCl In Stage 2, 40 kg of titanium chloride was added to 20 kg of sodium. The equation for the reaction is: TiCl4 + 4 Na ⟶ Ti + 4 NaCl Relative atomic masses (Ar): Na = 23 Cl = 35.5 Ti = 48 Explain why titanium chloride is the limiting reactant. You must show your working. – 6153
• Titanium is a transition metal. Titanium is extracted from titanium dioxide in a two-stage industrial process. Stage 1 TiO2 + 2 C + 2 Cl2 ⟶ TiCl4 + 2 CO Stage 2 TiCl4 + 4 Na ⟶ Ti + 4 NaCl In Stage 2, 40 kg of titanium chloride was added to 20 kg of sodium. The equation for the reaction is: TiCl4 + 4 Na ⟶ Ti + 4 NaCl Relative atomic masses (Ar): Na = 23 Cl = 35.5 Ti = 48 Explain why titanium chloride is the limiting reactant. -6097
• Tobacco mosaic virus (TMV) is a disease affecting plants. The diagram below shows a leaf infected with TMV. TMV can cause plants to produce less chlorophyll. This causes leaf discoloration. Explain why plants with TMV have stunted growth. – 7031
• Too many herring were caught by fishermen between 1960 and 1977. Herring can live for up to 12 years and begin to reproduce when 3 to 4 years old. Laws have been introduced to help conserve herring: • 1977 to 1981 – herring fishing was banned in the North Sea • 1984 to present day – control of mesh size of fishing nets • 1997 to present day – fishing quotas were introduced • 1998 to present day – herring fishing was banned in breeding grounds during the breeding season. Evaluate the effect of these laws on the conservation of herring stocks. Use data from Figure 3 and information from Figure 4 in your answer. – 7093
• Topic 4_Community Level Systems. Great tits and flycatchers are both birds. In a conservation project, scientists have built boxes for the birds to nest in. The scientists fixed the boxes on trees at different heights. The table shows how many birds of each type used the boxes for nesting. Draw a bar chart on the graph paper to show the scientists’ results. The results for great tits and flycatchers should be on the same axis. – 7617
• Transcription and translation are stages in the synthesis of proteins. The inheritance of different alleles affects the phenotype of an individual. A child is blood group O. The child’s mother is blood group A and the child’s father is blood group B. Explain how this child is blood group O. Use the Punnett square and probability in your answer – 10013
• Tungsten (W) is a metal. Tungsten is extracted from tungsten oxide (WO3). All other solid products from the extraction method must be separated from the tungsten. The table below shows information about three possible methods to extract tungsten from tungsten oxide. Evaluate the three possible methods for extracting tungsten from tungsten oxide. – 6147
• Tungsten (W) is a metal. Tungsten is extracted from tungsten oxide (WO3).  All other solid products from the extraction method must be separated from the tungsten. The table below shows information about three possible methods to extract tungsten from tungsten oxide. Evaluate the three possible methods for extracting tungsten from tungsten oxide. But three possible methods to extract tungsten from tungsten oxide. -6099
• Tungsten (W) is a metal. Tungsten is extracted from tungsten oxide (WO3). All other solid products from the extraction method must be separated from the tungsten. The table below shows information about three possible methods to extract tungsten from tungsten oxide.- 6115
• Two processes for producing ethanol are: • fermentation • hydration (reacting ethene with steam). The table below shows information about the processes. Give two advantages and two disadvantages of using fermentation to produce ethanol.  – 6159
• Two processes for producing ethanol are: • fermentation • hydration (reacting ethene with steam). The table below shows information about the processes. Give two advantages and two disadvantages of using fermentation to produce ethanol. – 6116
• Two students tested a green compound X. The students added water to compound X. Compound X did not dissolve. The students then added a solution of ethanoic acid to compound X. A gas was produced which turned limewater milky. Student A concluded that compound X was sodium carbonate. Student B concluded that compound X was copper chloride. Which student, if any, was correct? Explain your reasoning. – 6179
• Two students tested a green compound X.The students added water to compound X. Compound X did not dissolve. The students then added a solution of ethanoic acid to compound X. A gas was produced which turned limewater milky. Student A concluded that compound X was sodium carbonate. Student B concluded that compound X was copper chloride. Which student, if any, was correct? Explain your reasoning – 6133
• Ultrasound and X-rays are used to scan patients in hospital. Look at the information about these two different waves. Ultrasound and X-rays are used to scan different parts of the patient. Explain how ultrasound and X-rays are used and evaluate the risks and benefits of using these two different waves to scan patients in hospital. Use the information in the table in your answer – 7524
• Ultrasound and X-rays are waves used in hospitals to create images of the inside of the human body. To produce the images below, the waves must enter the human body.In this question you will be assessed on using good English, organising informationclearly and using specialist terms where appropriate.Describe the features of ultrasound and X-rays, and what happens to each type of wave after it has entered the human body – T
• Ultraviolet waves cover a range of frequencies. Scientists divide this range into three types, UVA, UVB and UVC. The table in Figure 14 shows the frequency range for each type. Earth’s atmosphere has on three types of ultraviolet radiation. Describe how the effects change with wavelength and the width of the arrows drawn indicates the amount of radiation that is involved – 8011
• Uranium metal can be produced by reacting uranium hexafluoride with calcium.UF₆ + 3Ca → 3CaF₂ + U.Describe how calcium and fluorine bond together to form calcium fluoride. The electron arrangement of each atom is shown.
• Vaccination can be used to prevent an illness in a person. Explain how a vaccination can prevent an illness. – 7025
• When a stent is fitted the doctor gives the patient an injection of anti-clotting drugs. The patient then takes one anti-clotting tablet every day. Anti-clotting drugs: • are very effective • can take a week to begin working fully • have been used for over 60 years • cost very little to make • do not work effectively if the patient eats certain types of food. The patient must have their blood tested every few weeks to check that the anti-clotting drugs are working. Evaluate the use of anti-clotting drugs in patients who have had a stent fitted. – 7015
• When flying, the pressure inside the cabin of an aircraft is kept at 70 kPa. The aircraft window has an area of 810 cm2 . Use data from Figure 1 to calculate the resultant force acting on an aircraft window when the aircraft is flying at an altitude of 12 km. Give your answer to two significant figures . – 6059
• When hydrogen is removed from an alkane, an alkene is formed. This is an example of a dehydrogenation reaction. 900 dm3 of propane, measured at room temperature and pressure, were dehydrogenated to form propene. Calculate the maximum mass, in kg, of hydrogen formed in this reaction. (relative atomic mass: H = 1.0; 1 mol of any gas at room temperature and pressure occupies 24 dm3 ) – 9036
• When the ramp is lowered, work is done to stretch a spring on the side of the ramp. Elastic potential energy is stored in the stretched spring. Figure 2 shows the ramp part way down in a balanced horizontal position. – 6060
• Wolfram’s Syndrome is a genetic disorder. It is caused by a recessive allele (n). In people with Wolfram’s syndrome, a protein does not function correctly. The diagram shows a pair of chromosomes from a person called Tim. Meena is expecting a baby. Tim is the father. Complete this genetic diagram. Wolfram’s syndrome can affect the pancreas. Meena and Tim’s doctor tells them that there is a chance that their baby will have problems controlling their blood glucose level. Explain why the doctor thinks this. Use information from part (i) and your biological knowledge. – 7612