Chapter 6, Problem 6.59P

Stearic acid ${\text{(C}}_{\text{18}}{\text{H}}_{\text{36}}{\text{O}}_{\text{2}}\text{)}$ is a fatty acid, a molecule with a long hydrocarbon chain and an organic acid group $\text{(COOH)}$ at the end. It is used to make cosmetics, ointments, soaps and candles and is found in animal tissue as part of many saturated fats. In fact, when you eat meat, you are ingesting some fats containing stearic acid. (a) Write a balanced equation for the combustion of stearic acid to gaseous products. (b) Calculate $\text{Δ}{\text{H}}_{rxn}^o$ for this combustion $(\text{Δ}{\text{H}}_f^o{\text{ of C}}_{\text{18}}{\text{H}}_{\text{36}}{\text{O}}_{\text{2}}=-948\text{kJ/mol)}.$ (c) Calculate the heat (q) released in kJ and kcal when 1.00 g of stearic acid is burned completely. (d) A candy bar contains 11.0 g of fat and 100. Cal from fat; is this consistent with your answer for part (c)?