Calculate the amount of heat required to heat water from 18 degrees to 58 degrees, if m = 8 kg.

Given:
T1 = 18 degrees Celsius – initial water temperature;
T2 = 58 degrees Celsius – required water temperature;
m = 8 kilograms is the mass of water;
c = 4200 J / (kg * C) – specific heat of water.
It is required to determine Q (Joule) – the amount of heat required to heat water from T1 to T2.
To determine the amount of heat, you must use the following formula:
Q = c * m * (T2 – T1) = 4200 * 8 * (58 – 18) = 4200 * 8 * 40 = 33600 * 40 = 1344000 Joules = 1.344 MJ.
Answer: to heat water, an energy of 1.344 MJ is required.