Exothermic reactions are chemical reactions that release energy in the form of heat, light, or sound. These reactions are characterized by a decrease in enthalpy, or the total heat content of a system. The energy released during an exothermic reaction is often manifest as an increase in temperature of the reacting materials or the surroundings.
Endothermic reactions, on the other hand, are chemical reactions that require an input of energy. These reactions are characterized by an increase in enthalpy, or the total heat content of a system. The energy required for an endothermic reaction is often manifest as a decrease in temperature of the reacting materials or the surroundings.
One way to differentiate between exothermic and endothermic reactions is to observe the change in temperature during the reaction. Exothermic reactions will generally result in an increase in temperature, while endothermic reactions will result in a decrease in temperature. However, it is important to note that temperature changes can also be influenced by other factors, such as the specific heat capacity of the reacting materials and the size of the reaction system.
There are many examples of exothermic reactions in everyday life. Combustion reactions, such as the burning of a candle or the ignition of a gas stove, are exothermic reactions that release energy in the form of heat and light. Similarly, the process of digestion in the human body is an exothermic reaction that releases energy to fuel the body's functions.
Endothermic reactions are also common in everyday life. Photosynthesis, the process by which plants convert light energy into chemical energy, is an endothermic reaction that requires an input of energy in the form of light. The process of melting ice, or the dissolution of solid substances in water, is also an endothermic reaction that requires an input of energy in the form of heat.
In summary, exothermic reactions are chemical reactions that release energy, while endothermic reactions are chemical reactions that require an input of energy. These reactions can be distinguished by observing the change in temperature during the reaction, but it is important to consider other factors that may influence temperature changes as well.