Chapter 16, Problem 64E

Without doing a numerical calculation, determine which of the following will reduce the free energy change for the reaction, that is, make it less positive or more negative, when the temperature is increased. Explain.

(a) ${\text{N}}_2\left(g\right)+3{\text{H}}_2\left(g\right)\to 2{\text{NH}}_3\left(g\right)$

(b) $\text{HCl}\left(g\right)+{\text{NH}}_3\left(g\right)\to {\text{NH}}_4\text{Cl}\left(s\right)$

(c) ${\left({\text{NH}}_4\right)}_2{\text{Cr}}_2{\text{O}}_7\left(s\right)\to {\text{Cr}}_2{\text{O}}_3\left(s\right)+4{\text{H}}_2\text{O}\left(g\right)+{\text{N}}_2\left(g\right)$

(d) $2\text{Fe}\left(s\right)+3{\text{O}}_2\left(g\right)\to {\text{Fe}}_2{\text{O}}_3\left(s\right)$