Question

What does exothermic mean?

Answer 1

Hint: Let’s understand the meaning of the term exothermic. In exothermic, the meaning of Exo is to give out and the meaning of thermo is heat. In simpler terms, it means something that liberates heat. Now we will learn about exothermic in detail.

Complete answer:
In thermodynamics, the process or a reaction to release energy from the system mainly in the form of heat and also can be released as light, electricity or sound is exothermic The term “exothermic” was created by Marcellin Berthelot. The concept is used a lot in physical chemistry. The chemical bond energy converts into thermal energy. Two types of chemical reactions that are found in nature are described by this term.
The exothermic reaction releases energy as the total energy of the reactants is more than the total energy of the products therefore the change in enthalpy will always be negative for an exothermic reaction. A strong acid when comes in contact with an aqueous solution dissociates completely with the release of heat. It is an exothermic reaction.
The liberation or release of heat is the exothermic change.
It is of two types: Physical Exothermic change and Chemical Exothermic change.
Physical exothermic change: When we dissolve NaOH in a distilled water, the solution will become warmer than it is already once NaOH is dissolved completely.
$NaOH(s)\xrightarrow{{{H}_{2}}O}N{{a}^{+}}(aq)+O{{H}^{-}}(aq)+Heat$
Chemical exothermic change: The example of it is combustion.
The burning of coal in the presence of air results in the formation of carbon dioxide and heat is also liberated with it.
$C+{{O}_{2}}\to C{{O}_{2}}+Heat$

Note:
The chemical reaction which absorbs heat from its surroundings is known as the endothermic reaction. The activation energy for the reaction to happen is given by the absorbed energy.
Examples: Dissolving ammonium nitrate in water.
                    Dissolving ammonium chloride in water.
                    Dissolving potassium chloride in water.