Hydrogen peroxide solution decomposes to form water and oxygen. A student adds the same mass of the same catalyst to two flasks of hydrogen peroxide solution and records the mass lost as oxygen escapes from each flask.
The flasks contain the same volume and concentration of hydrogen peroxide solution. The reactions are allowed to finish. Experiment Q is carried out at a higher temperature than experiment P.
| Measurement | Mass lost in experiment P in g\text{g}g | Mass lost in experiment Q in g\text{g}g |
|---|---|---|
| At 0 s | 0 | 0 |
| At 20 s | 0.30 | 0.55 |
| When the reaction is complete | 0.90 | 0.90 |
Calculate the mean rate of reaction during the first 20 s for each experiment.
Give your answers in g/s\text{g/s}g/s.
Explain why the rates are different and why the final mass losses are the same.
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.