Predict whether S is positive, negative, or close to zero for the following changes.

a) 2H₂(g) + O₂(g) ----> 2H₂O(g)

Answer

In this example there are three moles of gases on the reactants side and only two mole of gas on the product side. Even though the molecular complexity of H₂O(g) is greater than either H₂(g) or O₂(g), the numbers of moles of gases will define the S. S for this reaction is negative, the reactants are more disordered than the products.