Unit 3 : Equilibria

Question 1

How does a reversable reaction attain a state of dynamic equilibirium

Answer 1

Reversable reactions attain a state of dynamic equilibrium when the rates of forward and reverse reaction are equal.

Question 2

At equilibrium, the concentrations of reactants and products remain ——

Answer 2

At equilibrium, the concentrations of reactants and products remain CONSTANT. Concnetrations of reactants and products are unlikely to be equal at equilibrium.
The reaction has not stopped at equilibrium,

Question 3

Le chateliers Principle

Answer 3

An equilibrium will move to undo any change imposed upon it by temporarily favoruing either the forward or backward reation until equilibrium is reached.

Question 4

What does a catalyst do to the position of the equilibrium.

Answer 4

Catalyst increases rate at which equilibrium is achieved but no change to position of equilibrium.

Final percentage of products is the same with or without a catalyst at equilibrium.

Question 5

The haber process and relation to equilibrium

Answer 5

The effects of pressure
- high pressure increases the products at equilibrium

Use of temperature
- moderate temperatrues are used as high temperatures favour the reverse reaction which breaks down ammonia back to the reactants

The use of a catalyst
- use of iron catalyst increases the rate of ammonia production by achieving equilibrium more quickly (but does not produce more ammonia at equilibrium)

Recycling of unreacted gases
- Ammonia is easily sperated from unreacted nitrogen and hydrogen as ammonia has a much higher melting point. Unreacted nitrogen ans hydrogen are returned to the reaction vessel

Removal of product
Removal of ammonia product before equilibrium is achieved means the system tried to replace ammonia to try to achieve equilibrium.