Using the table of entropy values above, calculate S^o for a each of the following reactions,

b) 2C₂H₆(g) + 7O₂(g) ----> 6H₂O(g) + 4CO₂(g)

Answer

We notice that the calculated value is very negative. Just as we should predict on the basis of comparing the relative order/disorder of the reactants and products. There are 4 moles of product gases and 9 moles of reactant gases. Also there are 6 moles of products in the liquid phase and no reactants in the liquid phase. The products are much more ordered compared to the reactants. We must conclude the S of the reaction is negative.