Which change will make the reaction between zinc and dilute sulfuric acid slower?
Adding a catalyst to the reaction mixture
Heating the acid before adding the zinc
Using zinc powder instead of zinc pieces
Adding water to the acid before the zinc
127 exam-style questions on AQA GCSE Chemistry 6.1 Rate of reaction, covering 6.1.1a Calculating rates of reactions, 6.1.1b Gradient of a tangent as rate, 6.1.2 Factors which affect the rates of chemical reactions, 6.1.3 Collision theory and activation energy, and 6.1.4 Catalysts. Each one has a worked solution and a mark scheme showing where the marks go.