Absolute entropy and free energy

Question

Assignment:

Q1. Describe in detail the difference in absolute entropy values for the following pairs:
a) C(s, graphite) and C(s, diamond)
b) HCl(g) and HCl(aq)
c) CH₄(g) and CH₃CH₂CH₂CH₃(g)

Q2. a) Calculate the values of DeltaH° and DeltaS° for the following reaction at 25°C.
b) Use the values from a to calculate DeltaG° for the following reaction at 25°C.
c) Explain fully whether this reaction spontaneous or non-spontaneous at 25°C?

2 CH₃OH(g) + H₂(g) -> C₂H₆(g) + 2 H₂O(g) @ 25.0°C

Q3. a) Use thermodynamics to prove that the reaction shown below is non-spontaneous at room temperature (25 °C).
b) Calculate the temperature at which the reaction would just begin to become spontaneous.

MgCl₂(s) + H₂O(l) -> MgO(s) + 2 HCl(g)

Q4. Commercials make the claim that "a diamond is forever." Use thermodynamics to either prove or disprove this claim by calculating:
a) the entropy change.
b) the free energy change for the reaction below, and
c) by comparing DeltaGf° for graphite and diamond.

C(diamond) -> C(graphite)