Decomposition Reaction Chemistry Example 4

Follow the full solution, then compare it with the other examples linked below.

Example 4

hard
Hydrogen peroxide (H2O2\text{H}_2\text{O}_2) slowly decomposes into water and oxygen gas. Write the balanced equation. Adding manganese dioxide (MnO2\text{MnO}_2) speeds up the decomposition dramatically — what role does MnO2\text{MnO}_2 play, and is it consumed?

Solution

  1. 1
    Balanced equation: 2H2O2→2H2O+O22\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2. One compound breaks into two simpler substances — decomposition.
  2. 2
    MnO2\text{MnO}_2 acts as a catalyst. A catalyst speeds up a reaction without being consumed — it lowers the activation energy needed.
  3. 3
    After the reaction, the same amount of MnO2\text{MnO}_2 remains. It can be recovered and reused.

Answer

2H2O2→2H2O+O2;MnO2 is a catalyst (not consumed).2\text{H}_2\text{O}_2 \rightarrow 2\text{H}_2\text{O} + \text{O}_2; \quad \text{MnO}_2 \text{ is a catalyst (not consumed).}
This reaction is a classic decomposition often demonstrated in the 'elephant toothpaste' experiment. The catalyst changes the rate but not the products or overall energy change.

About Decomposition Reaction

A chemical reaction in which a single compound breaks down into two or more simpler substances (elements or simpler compounds), typically requiring an energy input.

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More Decomposition Reaction Examples

Example 1 easy

Write the balanced equation for the decomposition of water by electrolysis.

Example 2 medium

When heated, calcium carbonate decomposes: [formula]. Classify this reaction and explain why heat is

Example 3 easy

Classify: [formula].

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