Carbon dioxide and water vapour are greenhouse gases found in air.

1. (a)(i)Name one other greenhouse gas.[1]
2. (a)(ii)State one environmental problem that may be caused by an increase in the percentage of carbon dioxide in the air.[1]
3. (b)Draw the dot-and-cross diagram to show the bonding in a molecule of carbon dioxide. Only show the outer shell electrons.[1]
4. (c)Some power stations burn methane, CH4. Construct the equation to show the complete combustion of methane.[1]
5. (d)The carbon dioxide made in power stations can be removed by a reversible reaction with water. CO2(g) + H2O(l) ⇌ H2CO3(aq) The forward reaction is exothermic.
6. (d)(i)The concentration of carbon dioxide is increased. The temperature is kept constant. Predict and explain how the position of equilibrium changes.[2]
7. (d)(ii)The temperature of the water is increased. All other conditions are kept constant. Predict and explain how the position of equilibrium changes.[2]
8. (e)Carbonic acid, H2CO3(aq), is a weak acid.
9. (e)(i)What is the meaning of the term weak in weak acid?[1]
10. (e)(ii)Carbonic acid contains a small concentration of carbonate ions, CO32-(aq). If carbonic acid is pumped deep underground, the CO32-(aq) will react with metal ions to form insoluble carbonates. Write the ionic equation for the reaction of magnesium ions with CO32-(aq).[1]

This question uses a diagram from the original paper, which isn't shown here. Open the full paper from the past papers archive to see it.