Unit 3.2.3 - Equilibrium

Question 1

What sign shows a reaction is reversible?

Answer 1

See flash card

Question 2

What is a dynamic equilibrium?

Answer 2

It is where the forward and backward reaction are happening at the same rate and the concentrations of the reactants and products isn’t changing

Question 3

What condition is essential for a dynamic equilibrium?

Answer 3

A close system

Question 4

What is meant by the term a closed system?

Answer 4

A system where the reactants and products cannot escape

Question 5

If the position of equilibrium moves to the left which reaction is it favouring?

Answer 5

Backwards reaction

Question 6

If the position of equilibrium moves to the right which reaction is it favouring?

Answer 6

The forward reaction

Question 7

Which way does the position of equilibrium move if the reaction is favouring the forward reaction?

Answer 7

To the left

Question 8

Which way does the position of equilibrium move if the reaction is favouring the backward reaction?

Answer 8

To the right

Question 9

If the position of equilibrium moves to the left are more reactants or products formed?

Answer 9

Reactants

Question 10

If the position of equilibrium moves to the right are more reactants or products formed?

Answer 10

Products

Question 11

What is Le Chatelier’s Principle?

Answer 11

When a close system in dynamic equilibrium is disturbed, it responds in such a way as to oppose the change and restore the equilibrium

Question 12

A reversible reaction is exothermic in the forward direction what happens to the position of equilibrium if you increase the temperature?

Answer 12

The system will seek to oppose the increase in temperature by favouring the endothermic reaction, the backward reaction. This shifts the position of equilibrium to the left producing more reactants

Question 13

A reversible reaction has fewer moles on the right hand side what happens to the position of equilibrium if you increase the pressure?

Answer 13

The system will seek to oppose the increase in pressure by favouring the side with the fewest moles, this means it favours the forward reaction shifting the position of equilibrium to the right producing more products

Question 14

What happens if you increase the concentration of the reactants at equilibrium?

Answer 14

The system will seek to oppose the increase in concentration and try to git rid of the extra reactants by favouring the forward reaction shifting the position of equilibrium to the right producing more products

Question 15

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

Answer 15

No effect as it increases the forward and backward reaction at the same rate

Question 16

What two industrial processes do you have to apply Le Chatelier’s principle too?

Answer 16

Production of ethanol and methanol

Question 17

Ethanol can be produced through a reversible reaction between?

Answer 17

Ethene and steam

Question 18

What is the equation for the reversible reaction that produces ethanol?

Answer 18

C2H4 + H20 revers. C2H50H

Question 19

Name three conditions for the production of ethanol from ethane and steam?

Answer 19

1. ) 60-70 atmospheres
2. ) 300C
3. ) Phosphoric acid catalyst

Question 20

Is the production of ethanol and methanol an endothermic or exothermic reaction in the forward direction?

Answer 20

Exothermic

Question 21

Methanol can be produced through a reversible reaction between?

Answer 21

Hydrogen and carbon monoxide

Question 22

What is the equation for the reversible reaction that produces methanol?

Answer 22

2H2 + CO revers. CH30H

Question 23

Name three conditions for the production of methanol from hydrogen and carbon monoxide?

Answer 23

1. ) 50-100 atmospheres
2. ) 250C
3. ) A mixture of copper, zinc oxide and aluminium oxide as a catalyst

Question 24

Why is temperature compromised in the production of methanol and ethanol?

Answer 24

They are exothermic reactions and so a lower temperature would favour the forward reaction and produce more products, however if the temperature is too low it slows down the rate of reactant too much and so a compromised temperature is used to balance out the maximum yield and a fast reaction

Question 25

Why is pressure compromised in the production of methanol and ethanol?

Answer 25

There are fewer moles on the right hand side and so a higher pressure would favour the forward reaction and produce more products, however high pressures are hard to reach and so a compromised pressure is used to balance out the maximum yield and keep costs low

Question 26

Give three reasons why high pressures are hard to reach?

Answer 26

1. ) you need expensive equipment to cope with the high pressure
2. ) more dangerous as there is a higher chance of explosion
3. ) the energy to reach those pressures costs a lot

Question 27

How do they increase the yield of methanol and ethanol during its production?

Answer 27

They recycle back the unreacted products and that it can be used again

Question 28

What is the main use for methanol?

Answer 28

During the production of chemicals

Question 29

What can both methanol and ethanol be used for?

Answer 29

As fuels in cars

Question 30

Give three reasons why methanol and ethanol are seen as greener fuels?

Answer 30

1. ) they can be made from renewable resources
2. ) they produce fewer pollutants
3. ) can both be carbon neutral