Question

you injure your ankle playing your favorite sport. your coach grabs a disposable ice pack and breaks the inner seal. the salt inside dissolves into the water. she hands you the plastic pouch, which is quite cold to the touch. which description relates the energy change between the ice pack and your ankle? the pack is exothermic, absorbing heat from your ankle. the pack is endothermic, absorbing heat from your ankle. the pack is endothermic, releasing heat into your ankle.

Explanation:

To solve this, we recall the definitions of endothermic and exothermic processes. An endothermic process absorbs heat from the surroundings, while an exothermic process releases heat to the surroundings. When the salt dissolves in the ice pack, it absorbs heat (this is an endothermic dissolution), making the pack cold. So the ice pack, being cold, will absorb heat from the warmer ankle. So the correct description is that the pack is endothermic, absorbing heat from the ankle. The first option is wrong because exothermic releases heat (but the pack is cold, so it's absorbing, not releasing). The third option is wrong because endothermic processes absorb heat, not release.

Answer:

B. The pack is endothermic, absorbing heat from your ankle.