41 
Another T/F problem. You will need
to remember that the definition of A is 
42 
Calculation of DS_{tot}, DG, and DA for two phase changes (one melting, one vaporization) and for adiabatic expansion of a perfect gas into a vacuum. Note the similarities and differences between the three quantities. Note that the difference between DG and DA is often only a few kJ/mol (just as the difference between DH and DU is often only a few kJ/mol). It is very important to remember that if two phases are in equilibrium at constant T and P then they have the same molar free energy per mole (ie, the same G_{m}). 


48 
Numerical evaluation for a typical liquid of some of the derivatives for
which formulas can be derived and for which it is useful to look at approximate
values. A good exercise in cancelling
units. Please look at the magnitudes
of the values. 
425 
Calculation of DG, and DA for the isothermal expansion of a perfect gas. 
427 
Can be done very quickly. Emphasizes a very important point. 
428 
Part (a) can be done very quickly. Emphasizes a very important point. 
429 
A problem based on the mixing of gases, which is another classic problem in chemical thermodynamics. 
443 
Straightforward application of an equation derived in class. The problem does not state that P and T are constant, but if the system is at equilibrium and the free energy variable G is being considered then P and T must be constant and dG must be zero. Note that it cannot be guaranteed that dξ = 0 because the reaction could be shifted slightly forward or backwards while still being essentially at equilibrium. 
444 
Calculate ξ , which was called x in General Chemistry. 


440 
Another question about chemical potentials. If the chemical potentials of a component are the same in two phases then that component is in equilibrium If the chemical potentials of a component are different in different phases then that component in the phase in which its chemical potential is higher is unstable relative to the phase in which its chemical potential is lower (ie, ice at 298 K and 1 bar has a higher chemical potential than liquid water under the same conditions). Remember that for pure solids, pure liquids, and perfect gases the chemical potential is just the molar free energy. 