Carbon dioxide and sulfur dioxide are pollutants formed at power stations that burn fossil fuels such as coal.

1. (a)State one environmental problem caused by producing carbon dioxide as an atmospheric pollutant.[1]
2. (b)State one environmental problem caused by producing sulfur dioxide as an atmospheric pollutant.[1]
3. (c)(i)Sulfur dioxide produced at power stations can be removed by a process called flue gas desulfurisation. In flue gas desulfurisation, sulfur dioxide reacts with calcium carbonate. CaCO3(s) + SO2(g) → CaSO3(s) + CO2(g) The reaction needs to be fast to remove as much sulfur dioxide as possible. Explain, using ideas about particles, why the calcium carbonate needs to be a powder instead of a single solid lump.[2]
4. (c)(ii)Explain, using ideas about particles, why decreasing the temperature decreases the rate of the reaction between calcium carbonate and sulfur dioxide.[2]
5. (d)(i)Sulfur dioxide reacts with oxygen as shown. 2SO2 + O2 → 2SO3 Explain why sulfur dioxide is oxidised in this reaction.[1]
6. (d)(ii)Explain, using ideas about bond breaking and bond forming, why the reaction is exothermic.[2]
7. (d)(iii)Explain why the addition of a catalyst increases the rate of this reaction.[1]