A cashew is burned in a soda can calorimeter, and heats up 0.245 kg of water by 3.65 °C. The calorimeter was calibrated and had a calorimetry constant of 8.50 kcal/kg･°C.

Question

Given that fat contains 9.00 kcal/g, calculate the mass in g of the fat contained in the cashew. Assume that the cashew is composed primarily of fat.

This would be helpful if I could see the steps worked out! Thank you!

Answer 1

We first need to find out how much heat is generated burning the cashew.

q = mCcal∆T

q = heat = ?

m = mass of water = 0.245 kg

Ccal = calorimeter constant = 850 kcal / kgº

∆T = change in temperature = 3.65º

Solving for q we have...

q = (0.245 kg)(850 kcal / kgº)(3.65º)

q = 760.1 kcal

760.1 kcal x 1 g fat / 9.00 kcal = 84.5 g of fat (rounded to 3 sig. figs.)