# Hydrogen peroxide solution decomposes slowly at room temperature. When manganese(IV) oxide powder is added, the decomposition is much faster. Explain how the manganese(IV) oxide increases the rate of decomposition, and why the same mass of manganese(IV) oxide can be recovered at the end of the reaction.

> AQA A-Level Chemistry (7405) — 3.1.5 Kinetics · Explain · 5 marks

## Mark scheme (5 marks)

1. Manganese(IV) oxide acts as a catalyst
2. A catalyst provides an alternative (reaction) pathway with a lower activation energy
3. More particles (collisions) have energy greater than or equal to the (lower) activation energy
4. So the rate of reaction increases / decomposition is faster
5. The catalyst is not used up / not consumed in the reaction, so the same mass remains at the end

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