Chapter 10, Problem 10.93PAE

The graph below shows $\Delta \text{G}°$ as a function of temperature for the synthesis of ammonia from nitrogen and hydrogen.

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

a) Use the graph to estimate $\Delta \text{S}°$ for the ammonia synthesis reaction.

(b) Given that the standard free energy change of formation for ammonia ( $\Delta {\text{G}}_f°$ ) is -16.50 kJ/mol, estimate $\Delta \text{H}°$ for the ammonia synthesis reaction.