When a sample of food is burned, it caused the temperature of the water in a calorimeter containing 1990. g of water to increase by 8.9oC.

Question

I also want to know. What is the mass of the sample if it was 100% carbohydrate? (carbs =4.0 kcal/g)

Answer 1

We'll find the heat into the water: Q = m_wc_wΔT = (1990 g)(1 cal/gºCº)(8.9 ºC) = 17711 cal = 17.711 kcal

Now just cancel kcal and bring in carbs by

17.711 kcal *(1 g carb/4 kcal) = 4.4 g of carbs