In a chemical reaction, what usually happens in an exothermic reaction?

In an exothermic reaction, heat is released to the surroundings as a product of the reaction. This occurs when the total energy of the products is lower than that of the reactants. The energy difference is released in the form of heat, making the surroundings warmer. This release of heat can also be observed in processes such as combustion, where fuels react with oxygen, resulting in the production of heat and light. This characteristic of exothermic reactions is significant as it not only affects the temperature of the reacting substances but can also be harnessed in practical applications, such as heating systems or engines.

The other options do not accurately describe what happens during an exothermic reaction. For example, stating that heat is required contradicts the nature of exothermic processes, which instead generate energy. Similarly, the idea that heat has no impact or that it is absorbed from the environment misrepresents the fundamental characteristics of exothermic reactions.