A mixture of methane and air does not react at room temperature, even though the combustion of methane is exothermic. A single spark makes the whole mixture burn.
Statement 1: At room temperature, too few collisions between methane and oxygen molecules have energy equal to or greater than the activation energy.
Statement 2: The activation energy of the reaction is the same whether or not a spark is used.
Statement 3: Adding a catalyst would make the reaction release more energy overall.
Which statements are correct?
1 only
1 and 2 only
1 and 3 only
2 and 3 only
53 exam-style questions on Edexcel GCSE Chemistry 8.2 Heat energy changes in chemical reactions, covering 8.2.1 Exothermic and endothermic changes, 8.2.2 Bond breaking, bond making and overall energy change, 8.2.3 Calculating energy change from bond energies, and 8.2.4 Activation energy and reaction profiles. Each one has a worked solution and a mark scheme showing where the marks go.