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Q1.
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.
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Structure and Bonding:
Ethane and ethene are both hydrocarbons (they contain only carbon and hydrogen).Both molecules have 2 carbon atoms each.
Ethane has 6 hydrogen atoms, while ethene has only 4 hydrogen atoms.
They both have covalent bonds.
In ethane, the two carbon atoms are joined by a single C—C bond.
In ethene, the carbon atoms are joined by a double bond (C=C).
Both molecules also contain C—H bonds.
They are both small molecules.
Reactions:
Ethane and ethene both react with oxygen in complete combustion, forming carbon dioxide and water.They also both take part in incomplete combustion, producing carbon monoxide, water, and carbon (soot).
Incomplete combustion is more likely with ethene.
Ethene decolourises bromine water, showing it’s an alkene.
Ethane does not decolourise bromine water.
Ethene is more reactive than ethane.
Ethene can react with:
Hydrogen, to make ethane.
Water, to make ethanol.
Halogens, to make halogenoalkanes.
Ethene can do addition reactions and can also polymerise to form poly(ethene).
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