Equilibrium

Question 1

Equilibrium

Answer 1

Reversible reactions in a closed system eventually reach equilibrium
Concentration of reactants/products are the same
Forward/reverse reaction rate are the same

Question 2

Concentration affects equilibrium

Answer 2

If a substance is added the system will shift to use up the substance
If a substance is removed the system will shift to replace the substance

Question 2

Le Chatelier’s Principle

Answer 2

If a change is applied to a system at equilibrium, the system reacts in such a way to partially or fully counteract the change, in order to return to equilibrium

Question 3

Temperature affects equilibrium

Answer 3

If temperature is increased system will shift to lose temperature
If temperature is decreased system will shift to increase temperature
Heat is a product of an exothermic reaction
Heat is a reactant of an endothermic reaction

Question 3

Pressure affects equilibrium

Answer 3

If pressure is increased system will shift to decrease pressure
If pressure is decreased system will shift to increase pressure
To increase pressure the system shifts to favour the reaction with more moles of gas
To decrease pressure the system shifts to favour the reaction with less moles of gas

Question 4

Catalyst affects equilibrium

Answer 4

Lowers activation energy for both reactions
Equilibrium position does not change, equilibrium is reached faster

Question 5

Equilibrium Constant

Answer 5

Kc = [products] / [reactants]
If Kc < 10^-4, x is very small

ICE tables must be in concentration
C= n / v

Question 6

Open System

Answer 6

Allows matter and energy to be exchanged with the surroundings

Question 7

Closed System

Answer 7

Allows energy, but not matter, to be exchanged with the surroundings

Question 8

Reversibility of physical/chemical changes

Answer 8

Physical changes are usually reversible, whereas only some chemical reactions are reversible