B9 Cyclopropane is converted to propene when heated. [Figure 18.1: Diagram showing cyclopropane (H₂C-CH₂-CH₂) converting to propene (CH₃CH=CH₂)]

1. (a)Explain why cyclopropane and propene are isomers.[1]
2. (b)The graph shows how the concentration of propene in this reaction changes with time. [Figure 18.2: Graph showing concentration of propene in mol/dm³ versus time/min. The curve starts at 0, increases rapidly then gradually slows down, eventually leveling off.] Describe how the rate of this reaction changes with time. Explain your answer by referring to the graph.[2]
3. (c)Describe and explain the effect of increasing the concentration of cyclopropane on the rate of this reaction.[2]
4. (d)Describe and explain the effect of decreasing the temperature on the rate of this reaction.[2]
5. (e)Propene undergoes addition reactions. Two addition reactions of propene are shown in the diagram. Complete the diagram to show the missing name, formula and conditions. [Figure 19.1: Reaction diagram showing propene (CH₃CH=CH₂) undergoing two addition reactions. One reaction is with +steam, leading to a product where 'name' and 'formula' are missing. The other reaction is with +H₂, leading to propane (CH₃CH₂CH₃), where 'conditions 1' and 'conditions 2' are missing.][3]

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.