What amount of heat is released when cooling 100 g water from 90 to 20 ° C?

Initial data: m (mass of cooled water) = 100 g = 0.1 kg; t1 (water temperature before cooling) = 90 ºС; t2 (water temperature after cooling) = 20 ºС.

Reference values: C (specific heat of water) = 4200 J / (kg * K).

The amount of heat released when 100 grams of water is cooled can be determined by the formula: Q = C * m * (t1 – t2).

Let’s calculate: Q = 4200 * 0.1 * (90 – 20) = 4200 * 0.1 * 70 = 29 400 J or 29.4 kJ.

Answer: When 100 grams of water are cooled, 29.4 kJ of heat is released.