A researcher studying the nutritional value of a new candy places a 5.60 g sample of the candy inside a bomb calorimeter and combusts it in excess oxygen. The observed temperature increase is 2.89 ∘C. If the heat capacity of the calorimeter is 32.90 kJ⋅K−1, how many nutritional Calories are there per gram of the candy?
q = Ccal*delta T
q = 32,900 J * 2.89 = 95,081 J
q = 95,900 J x (1 cal/4.184 J) = 22,725 calories for 5.60 g candy.
22,725 calories x (1 g/5.60 g) = 4,058 calories/g candy
A food calorie is 1 kcal = 1,000 calories; therefore,
4,058 calories x (1 food calories/1000 calories) = 4.1 (rounded) kcal