Chemical equilibrium

Written by Dr. Ayesha Nadeem (Chemistry)

Class 10 · Chemistry · 9 questions

Name: ____________________ Date: ____________

A reaction that can go in both directions is called:
- A Irreversible
- B Reversible
- C Slow
- D Explosive
At equilibrium, the rates of the forward and backward reactions are:
- A Different
- B Zero
- C Infinite
- D Equal
In the Haber process, the product is:
- A Ammonia
- B Methane
- C Nitric acid
- D Sulphuric acid
Increasing the pressure on N2 + 3H2 giving 2NH3 shifts the equilibrium:
- A To the left
- B To the right
- C It stops
- D It does not shift
A catalyst in an equilibrium reaction:
- A Changes the equilibrium position
- B Speeds up reaching equilibrium
- C Increases the yield
- D Is used up
An equilibrium that has the same rates in both directions at constant conditions is called:
- A Equilibrium of forces
- B Boiling
- C Dynamic equilibrium
- D Static equilibrium
Adding more reactant to a system at equilibrium shifts it towards the:
- A Catalyst
- B Reactants
- C Products
- D No shift
The Haber process uses a temperature of about 450 degrees C because:
- A It makes ammonia solid
- B It is the lowest temperature possible
- C It stops the reaction
- D It balances rate and yield
A reaction that goes to completion in one direction is:
- A At equilibrium
- B Reversible
- C Catalysed
- D Irreversible

Answer key

1. B, 2. D, 3. A, 4. B, 5. B, 6. C, 7. C, 8. D, 9. D

A reversible reaction can proceed forwards and backwards.
Chemical equilibrium is dynamic: the two rates are equal.
Nitrogen and hydrogen combine to form ammonia.
The right side has fewer moles of gas (2 against 4), so more pressure favours it.
A catalyst makes equilibrium reached sooner but does not change the position.
The reactions continue at equal rates.
The system uses up the added reactant.
A higher temperature gives a faster rate but a lower yield.
For example, burning magnesium.