Question

According to the law of entropy, when hot and cold objects meet, heat flows from hotter to colder. What would be the end result of mixing hot water and cold water?
Responses

A The cold water would continue to heat up.The cold water would continue to heat up.

B The warm water would continue to cool down.The warm water would continue to cool down.

C The molecules in the cold water would slow down.The molecules in the cold water would slow down.

D All the water would reach an equilibrium temperature and heat would stop flowing.All the water would reach an equilibrium temperature and heat would stop flowing.

E The two volumes of water would balance out but the temperature of the two would keep fluctuating.

Answer 1

D. All the water would reach an equilibrium temperature and heat would stop flowing.

Explanation: Heat flows from the hotter water to the colder until they reach the same temperature (thermal equilibrium). At that point there is no net heat flow. Energy is conserved and entropy increases during the process; microscopic thermal fluctuations still occur but there is no macroscopic temperature difference driving heat transfer.