GCSE Chemistry – Rates of Reaction and Energy Changes – 1 – Exam Style Questions with Answers

Hydrogen peroxide decomposes to form water and oxygen.
The rate of this reaction can be found by measuring the volume of oxygen formed after
different time intervals.
Hydrogen peroxide solution is placed in a conical flask.
The apparatus is set up as shown in Figure 5.

At the end of the experiment with the catalyst added, the mass of the catalyst remaining
is found.
The method used to find the mass of the catalyst remaining is
filter the mixture of products and catalyst
determine the mass of the filter paper and solid catalyst
subtract the mass of a filter paper from the mass of filter paper and solid catalyst.
This method would not give the accurate mass of catalyst remaining.
Which of the following needs to be done to give a more accurate mass?

Some reactions are affected by the presence of a catalyst.
State the effect of a catalyst on a reaction.

Hydrogen peroxide decomposes to form water and oxygen.
The rate of this reaction can be found by measuring the volume of oxygen formed after
different time intervals.
Hydrogen peroxide solution is placed in a conical flask.
The apparatus is set up as shown in Figure 5.

State the name of the piece of apparatus labelled Z in Figure 5.

Hydrogen peroxide decomposes to form water and oxygen.
The rate of this reaction can be found by measuring the volume of oxygen formed after
different time intervals.
Hydrogen peroxide solution is placed in a conical flask.
The apparatus is set up as shown in Figure 5.

A solid catalyst can be used for this reaction.
The experiment is repeated under identical conditions but with the catalyst added.
In the experiment with the catalyst added………………………

Magnesium reacts with dilute sulfuric acid to form magnesium sulfate and hydrogen gas.
A student wants to find out the effect of temperature on the rate of this reaction.
The student used the following method.
step 1 pour 25 cm3 of dilute sulfuric acid into a conical flask
step 2 warm the acid until its temperature is 30 °C
step 3 add a piece of magnesium to the acid
step 4 start a stopwatch
step 5 wait until the reaction has finished
step 6 stop the stopwatch
step 7 repeat steps 1–6 but at 50 °C.
The reaction at 50 °C was faster than the reaction at 30 °C.
Give one reason, in terms of particles, why the reaction at 50 °C was faster than the reaction
at 30 °C……………….

The average rate of reaction in the first 20 seconds in cm of hydrogen produced per second is…………