What mass of water can be heated from 20C (degrees C) to boiling, burning 0.5 kg of charcoal?

Given:

m = 0.5 kilograms is the mass of charcoal;

q = 31 * 10 ^ 6 Joule / kilogram – specific heat of combustion of charcoal;

T0 = ​​20 degrees Celsius – initial water temperature;

T1 = 100 degrees Celsius – boiling point of water;

c = 4200 J / (kg * C) – specific heat of water.

It is required to determine how much water m1 (kilogram) can be heated.

Let’s find the amount of energy that will be released during the complete combustion of coal:

Q = q * m = 31 * 10 ^ 6 * 0.5 = 15.5 * 10 ^ 6 Joules.

Then the mass of water will be equal to:

m1 = Q / (c * (T1 – T0) = 15.5 * 10 ^ 6 / (4200 * (100 – 20)) =

= 15.5 * 10 ^ 6 / (4200 * 80) = 15500000/336000 = 46.1 kilograms.

Answer: You can boil water weighing 46.1 kilograms.