6.1 Endothermic & Exothermic Processes

Exothermic processes release heat to the surroundings (surroundings warm up; ΔH < 0). Endothermic processes absorb heat (surroundings cool; ΔH > 0).

Breaking bonds always absorbs energy; forming bonds always releases it.

Thermometer in solution reads the surroundings. Rises → exothermic.

Worked example: Dissolving NH₄NO₃ makes a cold pack → endothermic.