Question

The most important commercial process for generating hydrogen gas is the water-gas shift reaction:. CH4(g) + H2O(g) → CO(g) + 3H2(g). Use tabulated thermodynamic data to find ΔG° for this reaction at the standard temperature of 25°C. i found this to be. =1.423×102 kJ. Now calculate ΔG°1200 for this process when it occurs at 1200 K

Answer 1

The Gibb's free energy at a certain temperature is calculated by using the equation,
ΔG = - RT(ln K)

where K is the constant. We calculate this value by using the first conditions,
1.423x10^2 = -(8.314)(25 + 273) x (ln K)

Solving for K,
 K = 0.94418

Use the equation for the second set of conditions,

ΔG = - (8.314)(1200) x (ln 0.94418)

ΔG° at 1200 K is approximately 573.05 kJ

Answer 2

The Gibb's free energy at a certain temperature is calculated through the equation,
                                 ΔG = - RT(ln K)
where K is constant. Substituting the values from the first set of the given,
                               1.423x10^2 = -(8.314)(25 + 273) x (ln K)
Solving for the value of K gives us an answer of, K = 0.94418
Use the same equation to get the value of ΔG°1200
                                     ΔG = - (8.314)(1200) x (ln 0.94418)
The value of ΔG°1200 is approximately 573.05 kJ