# How much water taken at a temperature of 20 degrees can be heated to a boil

How much water taken at a temperature of 20 degrees can be heated to a boil, considering that all the energy released during the combustion of 2 kg of coal goes to heating the water?

Initial data: t0 (initial water temperature) = 20 ºС; m2 (mass of burnt coal) = 2 kg.

Reference data: tboil (boiling point of water) = 100 ºС; C (specific heat of water) = 4200 J / (kg * K); q (specific heat of combustion of coal) = 27 * 10 ^ 6 J / kg;.

All energy goes to heating water and the ratio is true:

Q1 = Q2: С * m1 * (tboil – t0) = q * m2.

m1 = q * m2 / (С * (tboil – t0)) = 27 * 10 ^ 6 * 2 / (4200 * (100 – 20)) = 160.7 kg.

Answer: 160.7 kg of water can be heated to a boil.

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