Question

The complete combustion of 0.661 g of a snack bar in a calorimeter (Ccal = 6.15 kJ/°C) raises the temperature of the calorimeter by 1.63 °C. Calculate the food value (in Cal/g) for the snack bar.

Answer 1

The heat calorimeter gained is same amount as the heat which snack bar gave.

(the heat calorimeter gained)=6.15 kJ/⁰C * 1.63⁰C = 10.0 kJ
(the calorie snack bar gave)=(food value)cal/g * 0.661g
1kJ=10³J
4.2J=1cal
(the heat calorimeter gained)=1.00 * 10⁴J
(the heat snack bar gave)=(food value) * 0.661 * 4.20= 2.77 * (food value)J
(food value)= 3.61cal/g