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.
Exothermic chemical reactions liberate heat. A simple and familiar example is the combustion of methane gas (CH 4). The balanced chemical reaction for this process is: CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2 H 2 O(g). We could write heat as one of the products on the right (products) side of the reaction if we wished.