How much alcohol must be burned to increase the temperature of 4 kg water taken at a temperature

How much alcohol must be burned to increase the temperature of 4 kg water taken at a temperature of 14 ° C to a temperature of 50 ° C.

The amount of heat with the complete combustion of alcohol:
Q = q * mс, where q is the specific heat of combustion of alcohol (we take q = 2.7 * 10 ^ 7 J / kg), mс is the mass of alcohol (kg).
The amount of heat for heating water:
Q = C * mw * ∆t, where C is the specific heat capacity of water (C = 4187J / (kg * K)), mw is the mass of water (mw = 4 kg), ∆t is the change in water temperature (∆t = tc – tн, where tк = 50 ºС, tн = 14 ºС).
q * mc = C * mw * (tk – tn);
mc = C * mw * (tc – tn) / q = 4187 * 4 * (50 – 14) / 2.7 * 10 ^ 7 ≈ 0.022 kg = 22 g.
Answer: You need to burn 22 g of alcohol.