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1.  Using the equation G =  H + T S  and a spreadsheet, calculate and graph the values of G at various temperatures for the following pairs of  H^o and S^o.  Start at 0 K and plot values of G every 20 K as the temperature increases to 500 K. 
 

Ho	So
150 kJ	350 J K-1
150 kJ	- 350 J K-1
- 150 kJ	350 J K-1
- 150 kJ	- 350 J K-1

2.  Use a spreadsheet to calculate and graph the reaction quotient, Q, and the free energy change, G, for

H2(g)  +  I2(s)  2 HI(g)

Go = 3.38 kJ

Start with an initial H₂ pressure of 0.90 atm and an initial HI pressure of 0.00 atm.  Plot values of Q (Q = P(HI)²/P(H₂ )) and G (G = G^o + RT ln Q) as the pressure of H₂  changes from 0.9 atm to 0.45 atm  in increments of 0.01 atm and the HI pressure increases in increments of 0.02 atm.

• The value of G is undefined when Q = 0.
• The value ofG (but not the value of G^o) changes as the concentrations of reactants and products change.
• This series of mixtures includes samples with Q > K and with Q < K.