What mass of water can be heated from 15 to 45 ° C, spending 1260 kJ of energy for this?

These tasks: t0 (water temperature before heating) = 15 ºС; t (water temperature after heating) = 45 ºС; Q (consumed thermal energy for heating water) = 1260 kJ.

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

SI system: Q = 1260 kJ = 1260 * 10 ^ 3 J.

We express the required mass of water from the formula: Q = C * m * (t – t0), whence m = Q / (C * (t – t0)).

Let’s calculate: m = 1260 * 10 ^ 3 / (4200 * (45 – 15)) = 10 kg.

Answer: Having spent 1260 kJ of thermal energy, it will be possible to heat 10 kg of water.