Unit 3 - Industrial Chemistry (Equilibria)

Question 1

What is a reversible reaction?

Answer 1

There is both a forward reaction (where reactants are made into products) and a reverse reaction (where product molecules break down to form reactants). In a reversible reaction, you can never obtain 100% conversion of reactants into products. Reversible reactions will always result in a mixture of reactants and products being formed.

Question 2

What is dynamic equilibrium/equilibrium position?

Answer 2

When the rate of the forwards and backwards reaction are equal. The concentration of the reactants and products remain constant but NOT necessarily equal.

Question 3

How can equilibrium be obtained?

Answer 3

In a closed system where the reaction is carried out in a sealed container and none of the reactants or products are lost.

Question 4

What does Le Chatelier’s principle state?

Answer 4

If a system at equilibrium is subjected to any change, the system will adjust itself to counteract the applied change.

Question 5

What happens to the equilibrium position when you increase the concentration of a reactant?

Answer 5

Adding a chemical that is present on either side of the equation will cause a shift in the position of the equilibrium, as the system adjusts to counteract the change.

Question 6

What happens when you alter the temperature?

Answer 6

Altering the temperature of an equilibrium mixture results in a shift depending on the enthalpy change of the reaction.

Question 7

Which side does an increase in pressure favour?

Answer 7

The side with the lower gas volume. Pressure can only affect the position of equilibrium if there is a change in the total gas volume.

Question 8

What happens when a catalyst is added?

Answer 8

Has no effect on the position of equilibrium. It does however allow equilibrium to be reached more quickly, or established at a lower temperature, which makes reactions more profitable.