What is the mass of water that can be heated from 20 to 100 degrees, transferring

What is the mass of water that can be heated from 20 to 100 degrees, transferring to it all the energy released during the complete combustion of 1 kg of coal?

Initial data: t0 (initial water temperature) = 20 ºС; t (final water temperature) = 100 ºС; m2 (mass of coal consumed) = 1 kg.

Reference values: C (specific heat capacity of water) = 4200 J / (kg * K); q (specific heat of combustion of coal) = 27 MJ / kg = 27 * 10 ^ 6 J / kg.

Since all the energy is transferred to water heating, the equality is true:

Q1 = Q2: С * m1 * (t – t0) = q * m2.

m1 = q * m2 / (С * (t – t0)).

Let’s do the calculation:

m1 = 27 * 10 ^ 6 * 1 / (4200 * (100 – 20)) = 80.36 kg.