What mass of water needs to be heated from 5 to 60 degrees, the amount of heat is 5 MJ.

Initial data: t0 (initial water temperature) = 5 ºС; t (temperature to which the water was heated) = 60 ºС; Q (consumed amount of heat for heating water) = 5 MJ = 5 * 10 ^ 6 J.

Constants: C (specific heat capacity of water) = 4200 J / (kg * K).

For the calculation, we assume that all the heat expended was used to heat the water.

Q = C * m * (t – t0), whence m = Q / (C * (t – t0)).

Let’s do the calculation:

m = 5 * 10 ^ 6 / (4200 * (60 – 5)) ≈ 21.6 kg.

Answer: It will be possible to heat 21.6 kg of water.