How may calories are there per gram of candy?

Question

A researcher studying the nutritional value of a new candy places a 5.20 g sample of the candy inside a bomb calorimeter and combusts it in excess oxygen. The observed temperature increase is 2.19 °C. If the heat capacity of the calorimeter is 41.20 kJ⋅K−1, how many nutritional Calories are there per gram of the candy?

Answer 1

Calories equate to joules as 1 Calorie = 4184 joules = 4.184 kJ. (note the cap C in the word Calorie)

q = mC∆T

q = heat = ?

m = mass = 5.20 g

C = specific heat = heat capacity of the calorimeter = 41.20 kJ/deg x 1 Cal/4.184 kJ = 9.85 Cal/deg

∆T = 2.19 degrees C (note: since we are using ∆T, it doesn't matter if you use K or ºC)

q = (5.20 g)(9.85 Cal/deg)(2.19 deg) = 112 Calories from 5.20 g

Calories per gram = 112 Cal/5.20 g = 21.6 Calories per gram