What process absorbs heat during a reaction?

The process that absorbs heat during a reaction is characterized as endothermic. In an endothermic reaction, the system takes in heat energy from the surroundings, leading to a decrease in temperature in those surroundings. This absorption of heat is a key aspect of many chemical reactions that require energy input to proceed, such as photosynthesis or the dissolution of certain salts in water.

Contrarily, an exothermic reaction releases heat into the environment, resulting in a temperature increase. Combustion reactions, typically exothermic, involve the burning of materials and release energy in the form of heat and light. Oxidation refers to the chemical reaction where a substance loses electrons, which can occur in both exothermic and endothermic processes, but it does not specifically define heat absorption. Understanding these fundamental differences highlights why endothermic is the correct term associated with heat absorption in chemical reactions.