A piece of copper weighing 1.2 kg, cooling down to a temperature of 20 ° C

A piece of copper weighing 1.2 kg, cooling down to a temperature of 20 ° C, released 114 kJ of heat. What is the initial temperature of the copper?

Problem data: m (mass of a cooled piece of copper) = 1.2 kg; t2 (final temperature) = 20 ºС; Q (heat released by a piece of copper) = 114 kJ (114 * 10 ^ 3 J).

Reference values: Cm (specific heat of copper) = 400 J / (kg * K).

We express the initial temperature of the taken piece of copper from the formula: Q = Cm * m * (t1 – t2), whence t1 = Q / (Cm * m) + t2.

Let’s calculate: t1 = 114 * 10 ^ 3 / (400 * 1.2) + 20 = 257.5 ºС.

Answer: The initial temperature of the taken piece of copper was equal to 257.5 ºС.