A 250g block of copper at 95∘C is quickly transferred into 200g of liquid water that is initially at 20∘C in a perfectly insulated calorimeter. Ignore any energy exchange with the calorimeter walls.
Respond to the following prompts related to the thermal interaction of the copper and the water.
(1) Identify the direction in which thermal energy is transferred immediately after the copper block is immersed in the water. Justify your answer with reference to macroscopic temperature differences.
(2) Describe, at the particulate (molecular) level, how collisions between copper atoms and water molecules lead to the change in temperature of each substance over time.
(3) State the macroscopic condition that signifies the moment at which the copper and the water have reached thermal equilibrium. Explain why energy transfer by molecular collisions still occurs at that moment even though there is no net transfer of thermal energy.