A university research group compares four trials for cracking vaporised long-chain alkanes. In every trial, the vapour is mixed with steam. The reactor is heated either to about 500 ∘C500\ ^{\circ}\text{C}500 ∘C or to above 800 ∘C800\ ^{\circ}\text{C}800 ∘C, with or without a catalyst.
Which trial uses the conditions for steam cracking?
Above 800 ∘C800\ ^{\circ}\text{C}800 ∘C without a catalyst
About 500 ∘C500\ ^{\circ}\text{C}500 ∘C with a catalyst
About 500 ∘C500\ ^{\circ}\text{C}500 ∘C without a catalyst
Above 800 ∘C800\ ^{\circ}\text{C}800 ∘C with a catalyst
131 exam-style questions on OCR GCSE Chemistry 6.2 Organic chemistry, covering 6.2.1 Crude oil and fractional distillation, 6.2.2 Cracking and dependence on hydrocarbons, 6.2.3 Functional groups and homologous series, 6.2.4 Reactions of alkanes, alkenes and alcohols, 6.2.5 Addition polymerisation and repeat units, 6.2.6 Naturally occurring polymers, 6.2.7 Chemical cells and fuel cells, and 6.2.8 Condensation polymerisation and how to make one. Each one has a worked solution and a mark scheme showing where the marks go.