13B - Entropy

Question 1

What are the units for entropy?

Answer 1

J K-1 mol-1

Question 2

Total entropy change for a reaction

Answer 2

ΔS(total) = ΔS(system) + ΔS(surroundings)

Question 3

∆S˚system is equal to :

Answer 3

∆S˚system = Σ S˚products - ΣS˚reactants

Question 4

∆S˚(surroundings) = ?

Answer 4

(−∆H˚(reaction)/T)

• T= Kelvin
• Convert ∆H to J by x 1000

Question 5

Gibbs law for feasibility equation

Answer 5

ΔG = ΔH − TΔSsystem

Question 6

For any spontaneous reaction what will ΔG be?

Answer 6

• Negative

Question 7

Why are some reactions thermodynamically feasible but they don’t occur spontaneously?

Answer 7

• Large activation energy needed (KINTETICALLY STABLE)

- Non standard conditions