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6.2 Reversible reactions and dynamic equilibrium

6.2 Reversible reactions and dynamic equilibrium

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Question 8

This question is about reactions between gases.

When brown nitrogen dioxide gas is cooled, it reacts to form colourless dinitrogen tetroxide gas.

The equation for this reversible reaction is:

nitrogen dioxide⇌dinitrogen tetroxide \text{nitrogen dioxide} \rightleftharpoons \text{dinitrogen tetroxide} nitrogen dioxide⇌dinitrogen tetroxide

This reversible reaction reaches equilibrium in a sealed container.

a.

How does the equation show that the reaction is reversible?

[1]
b.

Which two statements are correct when the reaction reaches equilibrium?

  • The forward reaction and reverse reaction are both endothermic.
  • No more nitrogen dioxide reacts.
  • The mass of each substance does not change.
  • The gases have escaped from the container.
  • The rates of the forward reaction and reverse reaction are equal.
[2]
c.

The initial gas in the sealed container is deep brown. Dinitrogen tetroxide is colourless.

How will the colour of the gas in the sealed container have changed when equilibrium is reached?

  • The gas will have become a deeper brown.
  • The gas will have become a paler brown.
  • The gas will have become colourless.
[1]
d.

The rate of reaction between gases is affected by changing the concentration.

Complete the sentences:

When the concentration of the reacting gases is increased, the rate of reaction ____________.

This is because at higher concentrations the number of particles in a given volume ____________.

This means that the frequency of collisions ____________.

[3]
e.

Give one other way of changing the rate of reaction between gases.

You should not refer to concentration in your answer.

[1]
Markscheme

6.2 Reversible reactions and dynamic equilibrium Questions

  1. GCSE
  2. /Chemistry
  3. /6.2 Reversible reactions and dynamic equilibrium

21 exam-style questions on AQA GCSE Chemistry 6.2 Reversible reactions and dynamic equilibrium, covering 6.2.1 Reversible reactions, 6.2.2 Energy changes and reversible reactions, 6.2.3 Equilibrium, 6.2.4 The effect of changing conditions on equilibrium (HT only), 6.2.5 The effect of changing concentration (HT only), 6.2.6 The effect of temperature changes on equilibrium (HT only), and 6.2.7 The effect of pressure changes on equilibrium (HT only). Each one has a worked solution and a mark scheme showing where the marks go.

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