A 0.50 kg block of copper is heated to 150 °C and quickly transferred to 0.20 kg of…
PHYSICS · Multi-part · A Level · Physics · Further mechanics and thermal physics · Further mechanics and thermal physics
Problem
A 0.50 kg block of copper is heated to 150 °C and quickly transferred to 0.20 kg of water at 25 °C contained in a calorimeter whose heat capacity is negligible. The system is sealed so that no energy is exchanged with the surroundings until equilibrium is reached.
After equilibrium, the copper block and the 0.20 kg of water are immediately transferred—without loss or gain of energy to the surroundings—into an insulated bucket that already contains 0.40 kg of water at 15 °C.
The specific heat capacity of copper is 385 J kg⁻¹ °C⁻¹, and the specific heat capacity of water is 4.18 × 10³ J kg⁻¹ °C⁻¹.
(a) Determine the equilibrium temperature T1 of the copper block and the initial 0.20 kg of water after their first interaction in the calorimeter.
(b) Using the value of T1 from part (a), determine the final equilibrium temperature T2 when the block–water combination is mixed with the additional 0.40 kg of water at 15 °C in the insulated bucket.
(c) Calculate the magnitude of the net energy gained by the 0.40 kg portion of water during the second interaction, and state whether the water is heated or cooled.