Equillibrium

Question 1

What is the equilibrium?

Answer 1

When the rate of the forward reaction is equal to the rate of backwards reaction, the system reaches dynamic equilibrium.

Question 2

Can equilibrium be reached in an open system?

Answer 2

No, the system should be closed, where no gaseous products can escape container.

Question 3

What type of reaction would occur on an open system?

Answer 3

An irreversable reaction.

Question 4

What is the difference between rate and extent?

Answer 4

Rate refers to how quickly reaction proceeds, while extent refers to degrees of conversion.`

Question 5

What 2 factors do manufactures consider when establishing reactions?

Answer 5

Rate and yield.

Question 6

What does competing equillibira refer to and what it one example?

Answer 6

When reactions occur simultaneously and the outcome of one reaction influences the other.
Eg. oxygen and co competing equilibria

Question 7

Why would small amounts of CO be harmful for someone when there is plenty of O2 around?

Answer 7

CO has an extremely high Kc and so its reaction is favoured in comparison to oxygens. CO will be more strongly absorbed by haemoglobin, preventing O2 from binding with HB.

Question 8

Does temperature effect Kc?

Answer 8

YES

Question 9

What is Kc a measure of?

Answer 9

The yield or extent of reaction.

Question 10

What does a low Kc mean and what does a high Kc mean?

Answer 10

Low: reverse reaction is favoured- more reactants
High: forwards reaction is favoured- more products

Question 11

What is the concentration quotient?

Answer 11

Q is a form of the equilibrium expression which is a measure of the relative amounts of products and reactants present. It indicates weather reaction is at equilibrium or not.

Question 12

What does a low Q mean and what does a high Q mean?

Answer 12

Low: reverse reaction is favoured- more reactants
High: forwards reaction is favoured- more products

Question 13

What is the Q and Kc expression used to identify extent of reaction?

Answer 13

Kc < Q < Kc

Question 14

What is the reactionship between Kc and n, where n is the value that the equation is changed by?

Answer 14

(kc) ^n

Question 15

What tool should you always use when calculating equillibrium concebtrations?

Answer 15

Rice table.

Question 16

What is Le Chatliers principle?

Answer 16

When a system in =m, is subjected to change equilibrium will shift in order to favour the reaction that partially oposes the change.

Question 17

How does adding product effect equilibrium?

same as removing reactant

Answer 17

System favours net backwards reaction.

Question 18

How does adding reactant effect equilibrium?

same as removing product

Answer 18

System favours net forwards reaction.

Question 19

How does diluting reaction effect equillibrium?

Answer 19

System favours reaction with most moles in order to increase concentration.

Question 20

How does increasing pressure effect equillibrium?

same as decreasing volume

Answer 20

System favours reaction with least moles in order to reduce volume.

Question 21

How does decreasing pressure effect equillibrium?

same as increasing volume

Answer 21

System favours reaction with most moles in order to

increase volume.

Question 22

How does increasing temp effect equillibrium of exothermic reaction?

Answer 22

System favours net backwards reaction in order to decrease temp.
Kc descreases

Question 23

How does decreasing temp effect equillibrium of exothermic reaction?

Answer 23

System favours net fowards reaction in order to increase temp.
Kc increases

Question 24

How does increasing temp effect equillibrium of endothermic reaction?

Answer 24

System favours net fowards reaction in order to increase temp.
Kc increases

Question 25

How does decreasing temp effect equilibrium of endothermic reaction?

Answer 25

System favours net backwards reaction in order to decrease temp.
Kc descreases

Question 26

How does adding an inert gas to a solution affect the equilibrium?

Answer 26

It increases the volume, hence pressure decreases. This means the equilibrium will shift to the side with the most amount of moles.

Question 27

How do you answer equilibrium questions?

Answer 27

1. describe the change
2. describe Le Chateliers principle
3. describe the equilibrium

Question 28

Answer the following question:
When more reactant is added, what colour will the solution be?
left= clear right= brown

Answer 28

When [O2] increases, the system will adjust to partially oppose the change and favour the reaction that decreases [O2]. Therefore the equilibrium shifts in a net forwards direction, producing more NO2 which increases browness.