Nitrogen(V) oxide decomposes on heating to form nitrogen(IV) oxide and oxygen. 2N2O5(g) → 4NO2(g) + O2(g) The table shows how the rate of reaction varies with the concentration of N2O5. concentration of N2O5(g) in mol/dm³ rate in mol/dm³/s 3.2 6.39 1.6 3.15 0.8 1.63

1. (a)(i)Describe how the rate of this reaction changes with the concentration of N2O5.[1]
2. (a)(ii)Explain your answer to (a)(i) in terms of collision theory.[2]
3. (a)(iii)Describe and explain the effect of increasing the temperature on the rate of this reaction.[2]
4. (b)(i)Sulfur dioxide is an atmospheric pollutant. Describe one source of the sulfur dioxide in the atmosphere.[1]
5. (b)(ii)The oxidation of sulfur dioxide to sulfur trioxide in the atmosphere is catalysed by nitrogen(IV) oxide. SO2 + NO2 → SO3 + NO NO + ½O2 → NO2 Nitrogen(IV) oxide speeds up the rate of reaction. Which other property of a catalyst is shown by these equations?[1]
6. (c)(i)An incomplete energy profile diagram for the oxidation of sulfur dioxide to sulfur trioxide is shown. energy reactants products progress of reaction On the diagram: • draw and label the pathway for the uncatalysed reaction, • draw and label the pathway for the catalysed reaction.[2]
7. (c)(ii)Is the reaction in (c)(i) exothermic or endothermic? Explain your answer.[1]

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