Which of the following describes an endothermic reaction?

An endothermic reaction is characterized by the absorption of heat from the surroundings, leading to a decrease in the temperature of the environment where the reaction occurs. This means that during the process, the system (the reacting substances) takes in thermal energy, which often results in cold sensations or lower temperatures around the reaction site.

This absorption of heat is fundamental in understanding various chemical processes and reactions, including photosynthesis and the dissolution of certain salts in water, where the surroundings may feel cooler as the reaction proceeds. In contrast, reactions that release heat would be classified as exothermic, causing an increase in the surrounding temperatures.