Enthalpy And Entropy

Question 1

Explain what entropy is

Answer 1

Entropy is the measure of dispersal of energy in a system, which is greater the more disordered a system is.

Question 2

How do i calculate entropy change?

Answer 2

ΔS = S products - S reactants

Question 3

What does a positive entropy value mean?

Answer 3

Means that a reaction is entropically feasible

Question 4

What does gibbs free energy (ΔG) tell us about a reaction?

Answer 4

Tells us if a reaction is feasible or not

Question 5

How do I calculate Gibbs’s free energy?

Answer 5

ΔG = ΔH - TΔS

H is enthalpy change
T is Temperature
S is entropy change.

Question 6

How do i know if a reaction is feasible or not in theory?

Answer 6

If ΔG is negative or zero.
Even if the reaction is calculated to be feasible you may not observe a reaction occurring. This can be due to the activation energy being too high or the rate of reaction is being very slow.