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Rates of Reaction and Energy Changes

Catalysts and enzymes

  • 3 things to know
  • Paper 2

Overview

What a catalyst is and why it is not used up and changes neither the products nor the yield, why industry uses catalysts, how a lower activation energy pathway speeds a reaction, and enzymes in fermentation and their damage at high temperatures.

What you need to know

Answer each one before you reveal it.

Your recallNot started
Key term

Define a catalyst.

Key term

Explain why a small quantity of a catalyst can be used over and over again.

Key term

Give one economic reason why industry uses catalysts.

Questions from this subtopic

Each one with the model answer underneath.

  1. 1

    Define a catalyst.

    Model answer

    A catalyst is a substance that speeds up the rate of a reaction without being chemically changed or used up itself.

  2. 2

    Does adding a catalyst change the products that a reaction makes?

    Model answer

    No, exactly the same products are formed.

  3. 3

    How does the mass of a catalyst at the end of a reaction compare with its mass at the start?

    Model answer

    It is unchanged, because the catalyst is not used up.

  4. 4

    Explain why a small quantity of a catalyst can be used over and over again.

    Model answer

    The catalyst is chemically unchanged at the end of a reaction, so it is still able to catalyse further reactions.

  5. 5

    Does a catalyst increase the final amount of product that a reaction makes?

    Model answer

    No, it only causes that product to form more quickly.

  6. 6

    Give one economic reason why industry uses catalysts.

    Model answer

    A catalyst lets the same amount of product be made faster and at lower temperatures, which saves energy and money.

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