Why Do Exothermic Reactions Give Off Heat?
There are many types of chemical reactions that took place around us. These reactions may give out light, sound, or heat. Reactions can be classified as endothermic or exothermic. Endothermic reaction happens when the system takes in energy in the form of heat. Exothermic reaction is the opposite because the energy is released in the form of heat.
Exothermic is defined as outside (exos) heat (thermos). Exothermic reactions give off heat because there is excess energy. The total energy in breaking the bonds is less than the energy released in forming new bonds. The excess energy is then discharged in the form of heat.
Exothermic reaction therefore produces heat going outside. This is very important in fire and explosion analysis.
Exothermic reactions happen in certain circumstances: burning of substances, explosion, corrosion of metals, rusting of steels, reaction of acid and base. In these reactions, we can observe that there is a rise in the temperature of the substance because heat is released. The heat may not be visible just like in the corrosion of metal but in explosion, the heat can be directly observed.
However, it must be noted that for exothermic reaction to occur there must be bonds that are formed. When new bonds are formed, there is less energy being used up. If new and stable bond is formed again, energy will be released and because of this, the energy needs to escape in the form of heat.
The heat in forming the bond is released because heat is one form of energy. During an exothermic reaction, there is an increase in the thermal energy while the internal energy of the system decreases after the heat is given off.
As long as any reaction gains heat, it will also release heat and this is what happens in exothermic reaction.