What is ΔG°rxn? CO(g) + 2 H₂(g) → CH₃OH(g) ΔGf° (J/mol K) -137.2 0 -162.0 A) -24.8 kJ B) -299.2 kJ C) +24.8 kJ D) 149.6 kJ E) +299.2 kJ

Question

Quizplus · Accepted Answer

To calculate ΔG°rxn, we need to use the formula:

ΔG°rxn = ΣΔGf°(products) - ΣΔGf°(reactants)

where Σ means the sum of, and ΔGf° is the standard free energy of formation of the compound at 1 atm pressure and 25°C.

Using the given ΔGf° values, we can calculate:

ΔGf°(CO) + 2ΔGf°(H2S) - ΔGf°(CH3OH)

= (-137.2 J/mol K) + 2(0 J/mol K) - (-162.0 J/mol K)

= -137.2 J/mol K + 162.0 J/mol K

= +24.8 J/mol K

Since the reaction is spontaneous at standard conditions (products are favored over reactants), the value of ΔG°rxn should be negative. Therefore, we choose answer A (-24.8 kJ) as the best choice.

What Is ΔG°rxn