A slice of apple weighing 3.0 g was burnt in a bomb calorimeter and produced a temperature rise of 2.4 K. In the same calorimeter, combustion of a 0.244 g sample of benzoic acid produced a temperature

Question

A slice of apple weighing 3.0 g was burnt in a bomb calorimeter and produced a temperature rise of 2.4 K. In the same calorimeter, combustion of a 0.244 g sample of benzoic acid produced a temperature rise of 3.2 K. The heat of combustion of benzoic acid at constant volume is -800 kcal/mol. If an average apple weighs 150 g, how many calories can be obtained from one average apple?

TestHub · Accepted Answer

Benzoic acid: q = 800 × 0.244/122 = 1.6 kcal for 3.2 K, so C cal = 1.6/3.2 = 0.5 kcal/K. Apple slice: q = 0.5 × 2.4 = 1.2 kcal per 3.0 g, i.e. 0.4 kcal/g. One 150 g apple gives 150 × 0.4 = 60 kcal (= 60 Calories). Answer: 0060.

Chemistry - Thermochemistry Question with Solution | TestHub

Doubts & Discussion