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.
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