Question

Calculate the standard Gibbs energy of reaction for the following: Cu2S (s) + O2 (g) -> 2 Cu (s) + SO2 (g) using the following information. Cu2S (s) -> 2 Cu (s) + S (s) has a standard Gibbs energy of reaction of 86.2 kJ/mol and S (s) + O2 (g) -> SO2 (g) has a standard Gibbs energy of reaction of -300.1 kJ/mol.

Answer 1

ΔG = -213.9kJ/mol

Step-by-step explanation:

It is possible to obtain standard Gibbs energy of reaction from the sume of another similar reactions (Hess's law).

Using the reactions:

(1) Cu₂S(s) → 2Cu(s) + S(s) ΔG = 86.2kJ/mol

(2) S(s) + O₂(g) → SO₂(g) ΔG = -300.1kJ/mol

The sum of both reactions gives:

Cu₂S(s) + O₂(g) → 2Cu(s) + SO₂(g)

ΔG = 86.2kJ/mol - 300.1kJ/mol

ΔG = -213.9kJ/mol