Final answer:
D) Thermal energy was used up in forming chemical bonds .Activating a cold pack by punching it initiates an endothermic reaction where chemical bonds form, absorbing
Step-by-step explanation:
The process that caused the cold pack to forcefully expel heat into its surroundings, thereby lowering its temperature, is an endothermic reaction.
When the pack is activated by punching it, a chemical inside the pack, typically ammonium nitrate, is released and reacts with water.
This reaction is endothermic, meaning it absorbs thermal energy from its surroundings, resulting in the cold sensation as the pack draws in heat.
Therefore, the correct answer is D) Thermal energy was used up in forming chemical bonds.
Cold packs work by utilizing an endothermic process. When a tube inside the pack is broken, a chemical reacts with water inside the pack, resulting in the absorption of heat energy.
This reaction quickly cools down the pack, allowing it to forcefully expel heat into its surroundings and lower its temperature.