Sulfur trioxide reacts with water to form sulfuric acid, a major contributor to acid rain. One origin of SO₃ is the combustion of sulfur, which is present in small quantities in coal, according to the following equation:

Given the thermochemical information below, determine the heat of reaction for this process:

Strategy We need to use the reactions whose enthalpy changes are known to construct a pathway that results in the desired reaction. In this case, we can see that SO₂ is formed in the first reaction we are given and then is consumed in the second. It is critical to pay attention to the precise stoichiometry of the given and desired reactions. The reaction of interest produces just 1 mole of SO₃, whereas the second reaction we are given produces 2 moles. So we will need to correct for that.

Transcribed Image Text:

3 S(s) + O₂(g) 2 O₂(g) → SO3(g)