When a 4 g peanut is burned, it warms 300 ml of water 45 °c. what was the energy content of the peanut?

Answer is: 13500 cal.

m (water) = V (water) ·d (water) = 300ml·1g/ml = 300g.

ΔT = 45°C, temperature change.

Calorie is amount of energy (heat) needed to increase the temperature of one gram of water by 1° C.

To raise the temperature of 300 grams of water for 45°C:

Heat in calories = mass in gram x temperature change °C x specific heat (cal / gram·°C). Q = m·ΔT·c.

Q = 300g · 45°C · 1cal/g·°C = 13500 cal.