Equilibrium + Chatelier's Principle

Question 1

Definition of equilibrium?

Answer 1

A state of balance between opposing forces or actions

Question 2

How is a dynamic equilibrium reached?

Graph?

Answer 2

• Forwards reaction is faster than backwards reaction at start
• Reverse reaction speeds up as forward slows down
• Rate of forwards become same as rate of backwards

https://shiken.ai/chemistry/dynamic-equilibrium

Question 3

What kind of system happens if dynamic system occurs?

Answer 3

Closed - no products can escape

Question 4

What does this graph mean?

https://www.shutterstock.com/image-vector/vector-scientific-graph-chart-chemical-equilibrium-2306187317

Answer 4

[Reactants] < [Products]

Equilibrium position: On the right

Question 5

What does this graph mean?

https://study.com/skill/learn/how-to-identify-chemical-equilibrium-from-a-graph-explanation.html
(THIRD GRAPH)

Answer 5

[Reactants] > [Products]

Equilibrium position: On the left

Question 6

State Le Chatelier’s Principle

Answer 6

The position of equilibrium will shift to oppose a change made to it

Question 7

CO + H2O <—–> CO2 + H2

How does the equilibrium yield of CO2 change when CO concentration increases? (3)

Answer 7

• Equilibrium shifts to the right
• To oppose increase in CO
• Increased yield of CO2

Question 8

CO + H2O <—-> CO2 + H2

How does the equilibrium yield of CO2 change when CO concentration decreases? (3)

Answer 8

• Equilibrium shifts to the left
• To oppose decrease in CO
• Decreased yield of CO2

Question 9

Pressure changes only affects what?

Answer 9

Gases

Question 9

2NO2 <—> N2O4

If the pressure increases? (4)

Answer 9

• Right hand side has fewer moles
• Equilibrium shifts to the right
• To oppose increase in pressure
• Yield of N2O4 increases

Question 10

2NO2 <—> N2O4

If the pressure decreases? (4)

Answer 10

• Left hand side has more moles
• Equilibrium shifts to the left
• To oppose decrease in pressure
• Yield of NO2 increases

Question 11

2NO2 <—> N2 + O4

If pressure increases or decreases?

Answer 11

No affect on position of equilibrium as number of moles is equal

Question 12

CH4 + H2O <—> CO + 3H2

Use Le Chatelier’s principle to explain why increasing the volume of the reaction container increases the equilibrium yield of hydrogen? (4)

Answer 12

• Increasing volume decreases pressure
• More moles on the right
• Equilibrium shifts to the right to oppose decrease in pressure
• yield of H2 increases

Question 13

What is an exothermic reaction?

Answer 13

Releases heat energy to surroundings so temperature to surroundings increase

△H is negative

Question 14

CH4 + H2O <—> CO + 3H2
△H = -206 kJ mol-1

If the temperature of the reaction decreases?

Answer 14

• Forward reaction is exothermic
• Equilibrium shifts to the right to oppose decrease in temperature
• Yield of CO + H2 increases

Question 15

What happens when a catalyst is added to a reversible reaction?

Answer 15

• The rate of both forwards + backwards reactions increase equally
• There’s no change to position of equilibrium
• Dynamic equilibrium is reached faster

Question 16

Why is it needed to compromise conditions for haber process?

Answer 16

• Higher pressure is too expensive
• 450℃ gives good yield in fast time

Cost, rate, yield

Question 17

Equation for Kc?

Answer 17

Question 18

How does an increase in pressure alter Kc?

Answer 18

No effect