Which term describes energy given off in a chemical reaction primarily as heat?

Which term describes energy given off in a chemical reaction primarily as heat?

• A. Endothermic reaction
• B. Catalyst
• C. Exothermic reaction
• D. Inhibitor

Answer: (C)

When energy is released as heat during a chemical reaction, the process is exothermic. In an exothermic reaction, the reactants start with more energy than the products, and the excess energy is emitted as heat to the surroundings. That transfer of energy makes the surroundings get warmer. End other options don’t describe heat being released. An endothermic reaction instead absorbs heat from the surroundings, often making things feel cooler. A catalyst changes how fast a reaction happens by lowering the activation energy but doesn’t determine whether energy is released or absorbed overall. An inhibitor slows the reaction rate, also without defining the energy change direction.

When energy is released as heat during a chemical reaction, the process is exothermic. In an exothermic reaction, the reactants start with more energy than the products, and the excess energy is emitted as heat to the surroundings. That transfer of energy makes the surroundings get warmer.

End other options don’t describe heat being released. An endothermic reaction instead absorbs heat from the surroundings, often making things feel cooler. A catalyst changes how fast a reaction happens by lowering the activation energy but doesn’t determine whether energy is released or absorbed overall. An inhibitor slows the reaction rate, also without defining the energy change direction.