Hydrogen peroxide solution decomposes slowly to make water and oxygen.
A student added 0.50 g of black manganese(IV) oxide powder to hydrogen peroxide solution. Oxygen was given off quickly. At the end of the experiment the student recovered 0.50 g of the black powder.
The equation for the reaction is:
2H2O2→2H2O+O22\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_22H2O2→2H2O+O2
Give two pieces of evidence that the manganese(IV) oxide is a catalyst in this reaction.
Explain how a catalyst increases the rate of a reaction.
Enzymes are catalysts.
Give one place where enzymes act as catalysts.
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.