Question

Oxides of sulfur are important in atmospheric pollution, arising particularly from burning coal. Use the thermodynamic data at 25 C given in the appendix to answer the following questions. a. In air, the oxidation of SO2 can occur: 1 2O2(g) SO2(g) S SO3(g). Calculate rG 298

Answer 1

-70.87 kJ

Step-by-step explanation:

Let's consider the following balanced equation.

1/2 O₂(g) + SO₂(g) ⇄ SO₃(g)

We can calculate the standard Gibbs free energy of reaction (ΔG°r) from the standard Gibbs free energies of formation (ΔG°f) using the following expression.

ΔG°r = 1 mol × ΔG°f(SO₃(g)) - 1/2 mol × ΔG°f(O₂(g) - 1 mol × ΔG°f(SO₂(g))

ΔG°r = 1 mol × (-371.06 kJ/mol) - 1/2 mol × 0 kJ/mol - 1 mol × (-300.194 kJ/mol)

ΔG°r = -70.87 kJ