Question

After a long time passes, the cold pack returns to room temperature. why?

O the chemical reaction that make it colder runs in the reverse direction, making it warmer
O cold is transferred from the cold pack to your teammate's ankle, making her ankle colder and the cold pack warmer
O more than one of these
O chemical bonds are formed, releases energy and heating up the cold pack
O none of these
O heat is transferred from your teammate's ankle to the cold pack, making her ankle colder and the cold pack warmer

Answer 1

A cold pack returns to room temperature due to heat transfer from the environment to the pack, eventually reaching thermal equilibrium. O cold is transferred from the cold pack to your teammate's ankle, making her ankle colder and the cold pack warmer

Step-by-step explanation:

After a long time, a cold pack returns to room temperature because heat is transferred from the warmer surroundings (like your teammate's ankle) to the colder pack. This process occurs until thermal equilibrium is reached, meaning the cold pack and the surroundings are at the same temperature. Initially, the cold pack gets cold due to an endothermic reaction, where ammonium nitrate (NH4NO3) dissolves in water and absorbs heat, causing the pack to draw thermal energy away from any warmer substance it's in contact with, such as an ankle.

Over time, the heat transfer is from the environment back into the cold pack until the temperature difference no longer exists.