Questions...

Can you explain again why certain values are negative or positive like in the spring/winter exam reaction #2
Fe(CO)6(l) + ClO2(g) FeCl3(s) + CO2(g)
ΔHrxnº = (783.5 kJ/mol) + 3(-102.5 kJ/mol) + (-399.49 kJ/mol) + 6(-393.509 kJ/mol) = -2284.5 kJ/mol

The ΔH and ΔG values you find in the tables are formation values. If something is being formed in a reaction, the values are correct as you find them in the table. If something in being consumed/desstroyed/used up in a reaction, the magnitude of the value in the table is correct, but the sign is wrong. If something is a reactant, change the sign; if it's a product, the sign in the table is correct.

I was wondering if you could answer #3 from problem set 10?

What is the molecular basis of enthalpy, entropy, and free energy? Let's start with entropy. Gaseous water is more disordered than liquid water, so we expect the entropy to be higher. For both enthalpy and free energy, gaseous water is more energetic than liquid water, so whether we're talking about heat (enthalpy) or overall energy (free energy), we expect the gas to be higher energy than liquid. Note, in this case, "higher" energy means "less negative" since all of these numbers are negative.

Other questions, let me know...