A powdered solid removes a pollutant gas by reacting with it in a sealed air-cleaning unit. The initial rate of the reaction is measured. In each alteration, all conditions not mentioned stay the same.
Which alteration would give a higher initial rate?
Adding a catalyst that is used for a different reaction
Increasing the pressure of the pollutant gas while keeping the temperature constant
Replacing the powder with the same mass of solid in one compact piece
Lowering the temperature while keeping the pressure of the pollutant gas constant
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.