Catalysts (GCSE Chemistry)

Catalysts

Catalysts

  • Catalysts increase the rate of reaction. By using a catalyst, the rate of reaction can be increased. Catalysts are not part of the reaction equation, since they are not used up in the reaction.
  • Catalysts decrease the activation energy. Catalysts will increase the rate of reaction by providing a different pathway for the reaction to occur. This pathway has a lower activation energy, therefore making it easier for the reaction to occur.
  • Different reactions require different catalysts. Catalysts are reaction specific, which means that we must use different catalysts for different reactions. Enzymes are examples of biological catalysts, which act as catalysts for living things.

 

Reaction Profiles for Catalysed Reactions

Similar to drawing the reaction profile of a reaction, we can also draw the reaction profile for a catalysed reaction as well.   

GCSE Chemistry - Catalysts
GCSE Chemistry – Catalysts

In a catalysed reaction, the activation energy is at a lower level. This means that less energy is needed for a reaction to take place. More particles are therefore likely to have enough energy for successful collisions to occur.

Download Free GCSE Chemistry Notes

    Effect of different solids on the catalytic decomposition of hydrogen peroxide solution

    You need to be able to describe an experiment to determine the effect of different catalytic solids on the decomposition of hydrogen peroxide solution.

    Method

    1. Gather your equipment. You will need a conical flask, capillary tube, measuring cylinder, container, bung, a solution of hydrogen peroxide and different solid catalysts.
    2. Add hydrogen peroxide into a flask. Add a known volume of hydrogen peroxide into a conical flask.
    3. Connect the flask to a measuring cylinder. Use a capillary tube to connect the two. The measuring cylinder should be upside down in a container of water, as seen in the diagram below. 
    GCSE Chemistry - Catalysts
    GCSE Chemistry – Catalysts
  • Add the catalyst. Add a known amount of the catalyst to the flask of hydrogen peroxide and immediately place the bung on the flask.
  • Measure the volume of gas produced. Using the scale on the measuring cylinder, measure the level of the water to determine the volume of gas produced in a given time. Note down your results.
  • Repeat the experiment. Repeat steps 1-5 with different solid catalysts to determine the effect of different solids on the rate of reaction. A better catalyst will produce a faster rate of reaction in a given time.
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