Question

Two substances, gold and granite, initially at different temperatures, come into contact and reach thermal equilibrium. The mass of gold is 20.2 g and its initial temperature is 58.2 ∘C. The mass of granite is 29.1 g and its initial temperature is 20.1 ∘C. What is the final temperature of both substances at thermal equilibrium? (The specific heat capacity of gold is 0.128 J/g⋅∘C; the specific heat capacity of granite is 0.79 J/g⋅∘C.)

Answer 1

heat lost by one + heat gained by other = 0.

[mass Au x specific heat Au x (Tfinal-Tinitial)] + [mass granite x specific heat granite x (Tfinal-Tinitial)] = 0

Substitute and solve for only unknown, i.e., Tfinal.