Enthalpy and Entropy Flashcards
1
Q
Define entropy.
A
A measure of the dispersal of energy in a system which is greater when the system is more disordered.
2
Q
What is the unit of standard entropy?
A
J K-1 mol-1
3
Q
How does temp affect entropy?
A
higher temp = higher entropy
4
Q
When a solid ionic lattice is dissolved in solution what happens to entropy?
A
Entropy increases because the ions are more disordered.
5
Q
How does change in no. gas molecules in a reaction affect entropy?
A
increase in no. gas molecules = increase in entropy
6
Q
Write Gibb’s free energy equation.
A
ΔG = ΔH - TΔS
7
Q
For a reaction to occur spontaneously ΔG must be positive of negative.
A
Negative
8
Q
What are the limitations of the predictions of feasibility made by using ΔG? (2)
A
- reaction may have high activation energy
- rate of reaction may be very slow
