Exothermic reactions, endothermic reactions, and catalysts

This lesson covers: 

  1. Exothermic reactions
  2. Endothermic reactions
  3. What are catalysts and how they work
  4. The advantages and disadvantages of catalysts

Endothermic reactions

Endothermic reactions take in energy from their surroundings, usually in the form of heat.

  • Examples include thermal decomposition reactions.
  • There is a fall in temperature as heat energy is taken in.
  • Everyday uses include cold packs for sports injuries.

What are Catalysts?

Catalysts speed up the rates of chemical reactions without being used up themselves.

Diagram showing a catalyst interacting with a reactant to form a product, with the catalyst being free to be used again.
  • They provide an alternative route for the reaction with a lower activation energy.
  • This means the minimum energy needed to start the reaction is lowered.
  • So a lower temperature can be used.
  • Catalysts can be reused multiple times.

Advantages and disadvantages of using catalysts.

Catalysts are useful in many industrial applications.

Advantages of using catalysts

  • They increase the speed of reactions.
  • They allow reactions to occur at lower temperatures.
  • They increase the yield of products.
  • They make processes more economical.

Disadvantages of using catalysts

  • They are expensive to buy initially.
  • Different reactions require different catalysts.
  • They can become contaminated or 'poisoned'.
  • They may need regular cleaning.