Question

Use standard free energies of formation to calculate ΔG∘ at 25∘C for each of the following reactions.

2CH₄(g)→C₂H₆(g)+H₂(g)
Express your answer using three significant figures.

Answer 1

To calculate ΔG∘ at 25∘C using standard free energies of formation, we can use the equation: ΔG∘ = ΣnΔG∘f(products) - ΣnΔG∘f(reactants). In this case, the reaction is 2CH₄(g) → C₂H₆(g) + H₂(g). Using the standard free energies of formation given in Appendix G, we can calculate the standard free energy change. The standard free energy change (ΔG∘) at 25∘C for the reaction 2CH₄(g) → C₂H₆(g) + H₂(g) is -65.58 kJ/mol.

Step-by-step explanation:

To calculate ΔG∘ at 25∘C using standard free energies of formation, we can use the equation:

ΔG∘ = ΣnΔG∘f(products) - ΣnΔG∘f(reactants)

where Σn is the stoichiometric coefficient of each species and ΔG∘f is the standard free energy of formation.

In this case, the reaction is 2CH₄(g) → C₂H₆(g) + H₂(g). Using the standard free energies of formation given in Appendix G, we can calculate the standard free energy change. Let's assume that the standard free energy of formation of CH₄(g) is -74.81 kJ/mol, the standard free energy of formation of C₂H₆(g) is -32.89 kJ/mol, and the standard free energy of formation of H₂(g) is 0 kJ/mol.

Using the equation, we have:

ΔG∘ = 2(-32.89) + 1(0) - 2(-74.81) = -65.58 kJ/mol

So the standard free energy change (ΔG∘) at 25∘C for the reaction 2CH₄(g) → C₂H₆(g) + H₂(g) is -65.58 kJ/mol.