Equilibrium

Question 1

What is a reversible reaction?

Answer 1

Products can reform initial reactants by re-reactants. Reactions take place in both directions at the same time.

Question 2

What is dynamic equilibrium.

Answer 2

Forward and backward reactions are happening at the same rate.

Question 3

What is equilibrium?

Answer 3

Concentration of products and reactants remains the same or constant.

Question 4

What factors affect the position of equilibrium?

Answer 4

Temperature
Pressure
Concentration

Question 5

How does concentration affect position of equilibrium ?

Answer 5

If the concentration of a recant is increased, the equilibrium will shift to the side of the reaction with the least moles therefore trying to reduce the concentration of the reaction.

Question 6

State La Chateliers principle.

Answer 6

If a factor affecting rate of reaction is altered, the position of equilibrium shifts to oppose the change to minimise the affect of the change.

Question 7

State how pressure affects rate of reaction.

Answer 7

When pressure increases, the reaction shifts to the region with fewer molecules to reduce the pressure.
When pressure decreases the reaction shifts to the side win more molecules.
But if same molecules the change in pressure has no effect.

Question 8

How does a change in pressure affect a reaction with equal moles on both sides ?

Answer 8

No effect

Question 9

What happens if you increase the temperature of an exothermic reaction ?

Answer 9

It will shift to favour the endothermic reaction to decrease the temperature of surroundings.

Question 10

What happens if you decrease the temperature of an exothermic reaction ?

Answer 10

Shifts to the right to favour the exothermic reaction to increase the surrounding temperature.

Question 11

What is an exothermic reaction and it’s symbol.

Answer 11

Negative triangle

Transfers energy to the surroundings to increase surrounding temperature.
Products lower than reactants

Question 12

What is the symbol and what is an endothermic reaction.

Answer 12

Positive triangle
Absorbs energy from surroundings to reduce surrounding heat.
Products more energy than reactants.

Question 13

What is the effect of a catalyst on equilibrium ?

Answer 13

Adding a catalyst does not affect the position of equilibrium. Only increases the rate of reaction so the position of equilibrium is revalued faster. But increases forward and backward reaction at same rate.

Question 14

How is % yield calculated ??

Answer 14

(Actual yield/ theoretical yield) x100

Question 15

What type of reaction is the hater process and how do you know this.

Answer 15

An exothermic reaction because an increase in temperature decreases yield of ammonia.

Question 16

What temperature does the haber process occur at and why ?

Answer 16

450 degrees Celsius because although % yield of ammonia will not be at its maximum, a compromise will be made so the reaction occurs at a reasonable rate with a Hugh enough rate to make the reaction economically viable.

Question 17

What pressure does the haber process occur at and why ?

Answer 17

200 atmospheres. Avery high pressure isn’t used because costs of minting a high pressure would be too high and would therefore mean the reaction wouldn’t be efficient.

Question 18

What % yield is created by the haber process.

Answer 18

20%

Question 19

What catalyst is added to the haber process and how does this work.

Answer 19

Iron

Increases rate of reaction without affecting position of equilibrium.

Question 20

In industry how is ethanol mainly produced ?

Answer 20

Hydration of ethene

Question 21

What type of reaction is hydration ethene to produce ethanol ?

Answer 21

Exothermic reaction

Question 22

How is ethanol production optimised during hydration of ethene.

Answer 22

Low temperature to about backward reaction because it is an exothermic reaction.

Question 23

How is it ensured that all ethene is used up in ethanol production ?

Answer 23

Increases steam concentration but not too much because it could dilute the phosphoric acid catalyst.

Question 24

What catalyst is added to ethanol production ?

Answer 24

Phosphoric acid.

Question 25

What does it mean if the Kc value is greater than 1 ?

Answer 25

Concentration of products is greater than concentration of reactants. Therefore equilibrium will lie to the right.

Question 26

What did it mean if the Kc value is < 1.

Answer 26

Concentration of products is less than concentration of reactants therefore equilibrium lies to the left.

Question 27

How does temperature affect Kc of an exothermic reaction.

Answer 27

Increasing temp shifts left. Kc decreases.

Decreasing temp shifts to the right. Kc increases.

Question 28

How does temperature affect the Kc of an endothermic reaction ?

Answer 28

Increasing temp shifts to the right. Kc increases.

Decreasing shifts left. Kc decreases.

Question 29

How does concentration affect Kc.

Answer 29

Doesn’t affect Kc because ration of products and reactants remains the same.

Question 30

How does a catalyst affect Kc.

Answer 30

No effect. Reaches position of equilibrium faster but ratio of products to reactants remains the same.