For the cold pack shown below, the temperature on the outside surface has dropped considerably from its initial temperature of 25 °C. Which of the following provides the best explanation for this temperature decrease?

The correct answer is D

Explanation:

In an endothermic process, energy travels from the surroundings into the system. The decrease in the temperature on the outside of the bag indicates that energy has moved from the surroundings into the system.

The other answers are incorrect. A bag cannot release “cold” into the surroundings since cold refers to the absence of heat. The surroundings become colder when heat is removed. Option B is incorrect because the cooling is due to the cold pack absorbing heat energy from its surroundings. Option C is incorrect because a cold pack absorbs heat energy from the surroundings, not vice versa.

a boiling water reactor does not boil the water. a pressurized water reactor boils the water faster. a pressurized water reactor is heated directly by the core. a pressurized water reactor does not use fission.