Benzoic acid is used to determine the heat capacity of bomb

Benzoic acid is used to determine the heat capacity of bomb calorimeters because it can be obtained in pure form and its energy of combustion is known very accurately (-3225 kJ/mol). Determine the heat capacity of a calorimeter that had a temperature increase of 5.199°C when 35.91 g of benzoic acid (MM = 122.12 g/mol) was used. Ccalorimeter = __kJ/°C

Solution

no of mol of benzoic acid used = 35.91/122.12 = 0.294 mol

1 mol benzoic acid = -3225 kj

heat released(q) = 0.294*-3225 = -948.15 kj

DT = 5.199 c

heat capacity(C) = q/DT

                 = 948.15/5.199

                 = 182.4 kj/c