Answer to Question #74915 in General Chemistry for Aj

Question

A bomb calorimeter, or a constant volume calorimeter, is a device often used to determine the heat of combustion of fuels and the energy content of foods.

In an experiment, a 0.6738 g sample of benzoic acid (C7H6O2) is burned completely in a bomb calorimeter. The calorimeter is surrounded by 1.190×103 g of water. During the combustion the temperature increases from 25.91 to 28.80 °C. The heat capacity of water is 4.184 J g-1°C-1.

The heat capacity of the calorimeter was determined in a previous experiment to be 961.3 J/°C.

Assuming that no energy is lost to the surroundings, calculate the molar heat of combustion of benzoic acid based on these data.

C7H6O2(s) + (15/2) O2(g) 3 H2O(l) + 7 CO2(g) + Energy