Which term means releases energy, such as heat?

• A. Hardenability
• B. Exothermic
• C. Conductivity
• D. Brittleness

Answer: (B)

Exothermic describes a process that releases energy to its surroundings, usually as heat. When a reaction is exothermic, the system loses energy and the surrounding area often gets warmer, which is the core idea behind the term. For example, burning fuel releases heat, and cement hydration releases heat as it cures.

The other terms don’t fit because they refer to different concepts: hardenability is about how deeply a material can be hardened through heat treatment, not energy release; conductivity is about how readily heat or electricity moves through a material, not whether energy is released; brittleness describes how likely a material is to fracture, not energy transfer or release.