The atmosphere contains a large number of gases including oxygen, nitrogen, carbon dioxide, sulfur dioxide, oxides of nitrogen, methane and chlorofluorocarbons (CFCs).

1. (a)(i)Carbon dioxide, methane and CFCs are greenhouse gases. State one effect of an increase in the atmospheric concentration of carbon dioxide and methane.[1]
2. (a)(ii)State one source of methane gas.[1]
3. (a)(iii)State one other environmental effect of the presence of CFCs in the atmosphere.[1]
4. (b)The formula of one chlorofluorocarbon is CFCl3. Draw the 'dot-and-cross' diagram to show the bonding in a molecule of CFCl3. Only draw the outer-shell electrons.[1]
5. (c)(i)Oxides of nitrogen are produced during the combustion of petrol (gasoline) in a car engine. Describe the chemical reaction that takes place within a car engine to form nitric oxide, NO.[1]
6. (c)(ii)Most of the nitric oxide and other pollutants present in the exhaust gases of a car are removed in a catalytic converter. Describe the redox reactions that happen within a catalytic converter.[2]
7. (d)Nitrogen dioxide is one of the causes of acid rain. Two moles of nitrogen dioxide react with one mole of water to make an aqueous solution of two acids only. One of these acids is nitric acid. Deduce the formula of the other acid.[1]