0.32 g of a walnut is burned under an aluminum can filled with 58.1 mL of water. The water temperature in the can increases by 3.1 °C. How many calories did the walnut release?

1.8 * 10² cal

Explanation:

When 0.32 g of a walnut is burned, the heat released is absorbed by water and used to raise its temperature. We can calculate this heat (Q) using the following expression.

Q = c * m * ΔT

where,

c: specific heat capacity of water

m: mass of water

ΔT: change in the temperature

Considering the density of water is 1 g/mL, 58.1 mL = 58.1 g.

Q = c * m * ΔT

Q = (1 cal/g.°C) * 58.1 g * 3.1°C

Q = 1.8 * 10² cal