2 m3 of water at 0 С turns into ice. How much energy is released in this case?

Water is at the crystallization temperature and energy is released only when the water turns into ice.

Q = λ * m, where λ is the specific heat of ice crystallization (λ = 3.4 * 10 ^ 5 J / kg), m is the mass of water (m = ρ * V, where ρ is the density of water (ρ = 1000 kg / m3), V is a given volume of water (V = 2 m3)).

Let’s calculate the released heat:
Q = λ * ρ * V = 3.4 * 10 ^ 5 * 1000 * 2 = 6.8 * 10 ^ 8 J = 680 * 10 ^ 6 J = 680 MJ.

Answer: When 2 kg of water turns into ice, 680 MJ of heat will be released.