How much heat is released during the hardening of 2 kg of water taken at a temperature

How much heat is released during the hardening of 2 kg of water taken at a temperature of 15 degrees Celsius? Find Q

Initial data: m (mass of water for hardening) = 2 kg; t0 (initial water temperature) = 15 ºС.

Reference data: C (specific heat) = 4200 J / (kg * K); λ (specific heat of ice melting, water crystallization) = 340 kJ / kg = 340 * 10 ^ 3 J / kg; t (temperature of transition of water into ice) = 0 ºС.

The released amount of heat: Q = Q1 (water cooling) + Q2 (transition to ice) = C * m * (t0 – t) + λ * m = (C * (t0 – t) + λ) * m.

Calculation: Q = (4200 * (15 – 0) + 340 * 10 ^ 3) * 2 = 806 000 J = 806 kJ.