Equilibria

Question 1

What is a reversible reaction?

Answer 1

A reaction that can go forwards or backwards depending on the conditions.

Question 2

What is an equilibrium reaction?

Answer 2

A reaction which does not go to completion and the reactants and products are present in fixed concentration ratios.

Question 3

What is dynamic equilibrium?

Answer 3

When the rate of the forward reaction and the rate of the backward reaction are the same in a closed system and the concentration of the products and the reactants remains constant. It is constantly occurring.

Question 4

What is a closed system?

Answer 4

One in which neither the reactants nor the products can escape from the reaction mixture.

Question 5

What are the four characteristics of equilibrium?

Answer 5

1. It is dynamic
2. It requires a closed system
3. The rate of the forward and backward reactions are the same
4. The concentrations of the reactants and products are the same

Question 6

How can we get to an equilibrium state?

Answer 6

We can either start with just the reactants or just the products.

Question 7

Can a chemical reaction reach equilibrium in an open system?

Answer 7

Yes, as long as the reaction does not lose any gas.

Question 8

If the concentrations of both reactants and products are constant, does that mean they are equal?

Answer 8

No

Question 9

What is the position of equilibrium?

Answer 9

The relative amounts of reactants and products in an equilibrium mixture.

Question 10

To where does the position of equilibrium shift when there is a higher concentration of products than reactants?

Answer 10

To the right (products)

Question 11

To where does the position of equilibrium shift when there is a lower concentration of reactants than products?

Answer 11

To the left (reactants)

Question 12

What does Le Chatelier’s principle state?

Answer 12

If one or more factors that affect dynamic equilibrium are changed, the position of equilibrium will shift to minimise this change.

Question 13

What effect will an increase in pressure have on the position of equilibrium?

Answer 13

The position of equilibrium will shift towards the side with the fewest gaseous molecules in order to decrease the pressure.

Question 14

What effect will a decrease in pressure have on the position of equilibrium?

Answer 14

The position of equilibrium will shift towards the side with the larger number of gaseous molecules to increase pressure again.

Question 15

If there is an equal number of gaseous molecules on both sides, what effect will a change in pressure have?

Answer 15

There will be no effect

Question 16

For an exothermic reaction, what is the effect of increasing temperature?

Answer 16

Equilibrium shifts to the left (reactants)

Question 17

For an exothermic reaction, what is the effect of decreasing temperature?

Answer 17

Equilibrium shifts to the right (products)

Question 18

For an endothermic reaction, what is the effect of increasing temperature?

Answer 18

Equilibrium shifts to the right (products)

Question 19

For an endothermic reaction, what is the effect of decreasing temperature?

Answer 19

Equilibrium shifts to the left (reactants)

Question 20

What effect does a catalyst have on the position of equilibrium?

Answer 20

None. It just increases the rate at which the forward and backward reactions take place.

Question 21

Why are high pressures expensive to produce?

Answer 21

1. High electrical energy costs for pumping
2. Equipment is expensive

Question 22

What is manufactured in the Haber Process?

Answer 22

Ammonia

Question 23

What are the conditions needed when carrying out the Haber Process?

Answer 23

1. Temperature of 450 degrees
2. Pressure of 200-1000atm
3. Catalyst Iron

Question 24

What is the advantage of using catalysts in the Haber and Contact Processes?

Answer 24

A lower temperature can be used to reduce energy costs as the catalyst speeds up the rate, allowing for this temperature compromise.

Question 25

What is needed to carry out the Contact Process?

Answer 25

1. Temperature of 450 degrees
2. Pressure of 1 or 2atm
3. Catalyst Vanadium (V) Oxide