Hydrogen peroxide decomposes to form water and oxygen. In Experiment 1, a student adds 0.5 g of manganese(IV) oxide to 25 cm325\,\mathrm{cm^{3}}25cm3 of hydrogen peroxide solution at 20 ∘C20\,^\circ\mathrm{C}20∘C. The student measures the volume of oxygen produced until the reaction stops.
In Experiment 2, the student adds 0.5 g of manganese(IV) oxide to 25 cm325\,\mathrm{cm^{3}}25cm3 of a more concentrated hydrogen peroxide solution at the same temperature. All other conditions are unchanged.
Which statement correctly compares Experiment 2 with Experiment 1?
The initial rate is greater and the final oxygen volume is greater.
The initial rate is unchanged and the final oxygen volume is greater.
The initial rate is unchanged and the final oxygen volume is unchanged.
The initial rate is greater and the final oxygen volume is unchanged.
122 exam-style questions on OCR GCSE Chemistry 5.2 Controlling reactions, covering 5.2.1 Measuring and interpreting rate of reaction, 5.2.2 Factors affecting rate and collision theory, and 5.2.3 Catalysts, activation energy and enzymes. Each one has a worked solution and a mark scheme showing where the marks go.