34 DUTY TO WARN it is really a Type B special relationship based on a profes-sional's general obligation to the community he serves.
Endothermic reactions: Heat is absorbed. 1) Photosynthesis: Plants absorb heat energy from sunlight to convert carbon dioxide and water into glucose and oxygen. 2) Cooking an egg: Heat energy is absorbed from the pan to cook the egg. Exothermic reactions: Heat is released.
Reactions are also classified as exothermic or endothermic depending on the direction of the standard enthalpy change. Exothermic reactions occur when the enthalpy change is negative, which means energy is lost to the environment and the chemical bonds are formed in the reactions.