[webassignbuddy]

Consider the reaction C₂H₆(g)    C₂H₄(g) + H₂(g). For this process, ΔH° = +137.0 kJ/mol and  ΔS° = +120.6 J/mol·K. Based on these data (note carefully) and assuming ΔH° and ΔS° are temperature independent, answer the following questions.

a. Does this reaction "favor" reactants or products at 25ºC? reactants (CORRECT)
b. At 25ºC is the reaction driven (dominated) by the entropy or enthalpy? enthalpy (CORRECT) because ΔG = ΔH° - TΔS° = 137000 - (25)(120.6) = +133985, so enthalpy dominates.
c. Would an increase in temperature favor the reactants or products? reactants (CORRECT)
d. At what temperature would the equilibrium constant (K) equal unity (1.0)?

I don't understand how to solve for d!

Do I use the equation ln K = (ΔS°/R) - (ΔH°/RT)?

[Borek]

Nothing analytical about the problem, moving to Physical Chemistry.

[webassignbuddy]

Anybody willing to help me in the right direction??

[Big-Daddy]

yes, that equation is correct, and it comes from the two equations ΔG° = ΔH° - TΔS° and ΔG=ΔG°+RTln(Q) of which a special case is that when Q=K (i.e. at equilibrium) ΔG=0.