Reversible Reactions, Haber Process and Le Chatelier Principle

Unit 6.2, Unit 10.1

What is a reversible reaction?

The products of the reaction can react again to produce the original reactants.

How do reversible reactions reach equilibrium?

If they are in a closed system.

What does a closed system prevent?

Loss of reactants or products.

What is equilibrium?

The rate of forward and backward reaction are equal.

What happens when the position lies to the right?

There are more products than reactants.

What happens when the position lies to the left?

There are more products than reactants.

What are conditions that affect equilibrium?

Temperature, Concentration and Pressure

What does it mean when the forward reaction is exothermic?

It release heat from the surroundings and becomes heat

What does it mean when the backward reaction is endothermic?

It absorb heat from the surroundings and becomes cold

What happens when the temperature is increased?

Endothermic side is favoured to re-establish equilibrium

What happens when the temperature is decreased?

Exothermic side is favoured to re-establish equilibrium

What happens to amount of energy in reversible reactions?

The amount of energy released and absorbed is equal

What is Le Chatelier’s Principle?

Changing the conditions of a reversible reaction the system will react to counteract that change by shifting the position of equilibrium

What does LCP state about the Yield in a reversible reaction?

It is affected by changing temperature, pressure and concentration

What does LCP state about the position of Equilibrium in a reversible reaction?

It is used to determine the effect of changes condition on yield in reactions

What happens when temperature is increased?

Equilibrium favours the ==endothermic== side to oppose the change. Equilibrium moves the ==endothermic side/RHS.== Yield of product decreases.

What happens when temperature is decreased?

Equilibrium favours the ==exothermic== side to oppose the change. Equilibrium moves the ==exothermic side/LHS.== Yield of product increases.

What happens when pressure is increased?

Equilibrium favours the ==fewer moles== of gas to oppose the change. Equilibrium moves the ==fewer moles side.== Yield of product increases.

What happens when pressure is decreased?

Equilibrium favours the ==greater moles== of gas to oppose the change. Equilibrium moves the ==greater moles side.== Yield of product increases.

What happens when number of molecules are equal?

Pressure has no effect on position of equilibrium. Yield is not affected.

When is LCP for pressure used?

For gases

When is LCP for concentration used?

For solutions

What happens when concentration is increased?

Equilibrium moves to the ==right== to oppose the change. Yield of product increases.

What happens when concentration is decreased?

Equilibrium moves to the ==left== to oppose the change. Yield of product decreases.

What effect catalyst do have on equilibrium?

They do not alter the position equilibrium, only increase the rate of forward and backward reactions