Question

A researcher studying the nutritional value of a new candy places a 3.50 g sample of the candy inside a bomb calorimeter and combusts it in excess oxygen. The observed temperature increase is 2.92°C. If the heat capacity of the calorimeter is 41.60 kJ.K", how many nutritional Calories are there per gram of the candy? Calories per gram of candy: Cal/g

Answer 1

-Heat energy given by candy = heat absorbed by calorimeter

Thus

Heat taken by calorimeter = heat capacity x rise in temperature

= 41.60 kJ/K x 2.92 K

= 121.472 kJ

in kilo calories the energy absorbed by calorimeter = 121.472kJ x 0.239 kcal /1 kj =29.032 kcal

In nutritional studies 1 Cal = 1 kcal

thus the 3.5 g candy has nutritional value = 29.032 Cal

1g of candy has nutritional value = 1g x 29,032Cal /3.5g =8.295 Cal/g