✅10 - Equilibrium I

Question 1

What can reversible reactions reach?

Answer 1

Dynamic euqillibrium

Question 2

As the reactants are used up, what happens to the forward reaction?

Answer 2

It slows down

Question 3

When is dynamic equilibrium achieved?

Answer 3

When the forwards reaction is going at exactly the same rate as the backwards reaction and the amounts of reactants and products aren’t changing

Question 4

What does dynamic equilibrium happen in?

Answer 4

A closed system

Question 5

What is Kc?

Answer 5

The equilibrium constant

Question 6

What does Kc give you an idea of?

Answer 6

How far to the left or right the equilibrium is

Question 7

What is a homogeneous system?

Answer 7

A system in which everything is in the same physical state

Question 8

What can Kc be worked out using?

Answer 8

The concentrations of reactants and products at equilibrium

Question 9

Which reactants and products are included in Kc for homogeneous equilibria?

Answer 9

All of them

Question 10

What is the equation for Kc?

Answer 10

[products]/[reactants]

Question 11

What is a heterogeneous equilibria?

Answer 11

One in which not everything is in the same physical state

Question 12

What is not included in the Kc expression for heterogeneous equilibria?

Answer 12

Pure liquids or solids

Question 13

Why are solids not included in the Kc expression?

Answer 13

Because their concentration is constant

Question 14

Why are pure liquids not included in the Kc expression?

Answer 14

Because their concentration is constant

Question 15

Why aren’t catalysts included in the Kc expressions?

Answer 15

Because they don’t affect the equilibrium concentrations of the products or reactants

Question 16

How do catalysts affect equilibrium?

Answer 16

They increase the rate at which equilibrium is reached

Question 17

What is Le Chatelier’s principle?

Answer 17

If there is a change in concentration, pressure or temperature, the equilibrium will move to help counteract the change

Question 18

If the position of equilibrium is altered, what will happen?

Answer 18

The amounts of products and reactants at equlibrium change

Question 19

What happens if the concentration of a reactant is increased?

Answer 19

The equilibrium shifts to the right to use up the extra reactants

Question 20

What happens if the concentration of a product is increased?

Answer 20

Equilibrium shifts to the left to remove the extra product

Question 21

What happens if the pressure is increased?

Answer 21

The equilibrium shifts to the side with fewer moles, reducing the pressure

Question 22

What does pressure affect?

Answer 22

Gases

Question 23

What happens if pressure is decreased?

Answer 23

Equilibrium shifts to the side with the most moles to raise the pressure

Question 24

What happens if temprature is increased?

Answer 24

The equilibrium shifts to the endothermic side to absorb the heat

Question 25

What happens if temperature is decreased?

Answer 25

The equilibrium shifts to the exothermic side to replace the heat

Question 26

What happens if the forward reaction is endothermic?

Answer 26

The reverse reaction is exothermic

Question 27

How are conditions chosen in industry?

Answer 27

As a compromise

Question 28

What are conditions chosen to produce?

Answer 28

A high rate and high yield

Question 29

How is ethanol made?

Answer 29

From ethene and steam

Question 30

What is the equation for ethanol production?

Answer 30

C2H4 + H2O –> C2H5OH

Question 31

What pressure is used for ethanol production?

Answer 31

60-70 atm

Question 32

What temperature is used for ethanol production?

Answer 32

300 degrees

Question 33

What catalyst is used for ethanol production?

Answer 33

Phosphoric acid

Question 34

Why is the temperature for ethanol production relatively low?

Answer 34

Because the forward reaction is exothermic, so lower temperatures favour it