Catalyst Examples in Chemistry

Start with the recap, study the fully worked examples, then use the practice problems to check your understanding of Catalyst.

This page combines explanation, solved examples, and follow-up practice so you can move from recognition to confident problem-solving in Chemistry.

Concept Recap

A substance that increases the rate of a chemical reaction by providing an alternative pathway with lower activation energy, without being permanently consumed or chemically altered in the process.

A helper that makes the reaction easier but isn't used up in the process.

Read the full concept explanation →

How to Use These Examples

  • Read the first worked example with the solution open so the structure is clear.
  • Try the practice problems before revealing each solution.
  • Use the related concepts and background knowledge badges if you feel stuck.

What to Focus On

Core idea: Catalysts lower activation energy by providing an alternative, easier reaction pathway.

Common stuck point: Catalysts don't change the final products or the energy released—just the speed.

Sense of Study hint: When a problem involves a catalyst, remember it affects rate but not equilibrium position. First identify the catalyst — it appears in the mechanism but not in the overall equation. Then note it lowers E_a for both forward and reverse reactions equally. Finally, check that the catalyst is regenerated by the end of the mechanism.

Worked Examples

Example 1

easy
In the decomposition of hydrogen peroxide, \text{MnO}_2 acts as a catalyst: 2\text{H}_2\text{O}_2 \xrightarrow{\text{MnO}_2} 2\text{H}_2\text{O} + \text{O}_2. Explain the role of \text{MnO}_2.

Solution

  1. 1
    \text{MnO}_2 provides an alternative pathway with lower activation energy for the decomposition.
  2. 2
    It speeds up the reaction but is not consumed — it can be recovered unchanged after the reaction.
  3. 3
    Without the catalyst, \text{H}_2\text{O}_2 decomposes very slowly at room temperature.

Answer

\text{MnO}_2\text{ lowers } E_a\text{ and is not consumed}
Catalysts are essential in both industrial chemistry and biology (where they are called enzymes). They increase reaction rates without altering the products or the equilibrium position.

Example 2

medium
Explain the difference between a homogeneous catalyst and a heterogeneous catalyst. Give one example of each.

Practice Problems

Try these problems on your own first, then open the solution to compare your method.

Example 1

easy
Enzymes are biological catalysts. Does an enzyme change the \Delta H of a biochemical reaction?

Example 2

medium
A catalyst is added to a reaction and the reaction finishes faster. What changes, and what does not change about the reaction?
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Background Knowledge

These ideas may be useful before you work through the harder examples.

activation energy