13.3.2 - Gibbs Energy and Equilibrium

Question 1

What is the equation that links Gibbs free energy and the Equilibrium constant?

Answer 1

Gibbs Energy = -RT*ln(K)

Question 2

How can we rearrange the equation linking Gibbs free energy and equilibrium constant to make K the subject?

Answer 2

K = e^-Gibbs Energy/RT

Question 3

What does it mean if Gibbs free energy is negative when using the rearranged formula: K = e^-Gibbs Energy/RT ?

Answer 3

The value will be positive
So K is greater than 1
Meaning products are favoured

Question 4

What does it mean if Gibbs free energy is positive when using the rearranged formula: K = e^-Gibbs Energy/RT ?

Answer 4

The value will be negative
So K is less than 1
Reactants are favoured

Question 5

What is the resultant equation when the 2 formulas for Gibbs free energy are combined?

Answer 5

ln(K) = - ethalpy change/RT + Entropy of system/R

Question 6

What does the reaction favour is equilibrium constant is greater than 1 or less than 1?

Answer 6

Greater than 1 = Products favoured
Less than 1 = Reactants favoured

Question 7

What happens if the value of K becomes very large due to Gibbs free energy being a large negative value in the formula K = e^-Gibbs Energy/RT?

Answer 7

The reaction effectively goes to completion

Question 8

What happens if the value of K becomes very small due to Gibbs free energy being a large positive value in the formula K = e^-Gibbs Energy/RT?

Answer 8

The reaction does not proceed to a certain extent

Question 9

What are the 2 cases where a reaction may go against what its feasibility suggests?
E.g A feasible reaction that does not occur or the other way around

Answer 9

Kinetic stability - Activation energy is very high
Non-standard conditions for example changing conditions like increasing concentration to make a reaction that is not feasible occur.