EXOTHERMIC AND ENDOTHERMIC REACTION

 EXOTHERMIC REACTION 

A chemical reaction in which heat energy is released along with the formation of produce is known as exothermic reaction.

A + B —> C + D +heat

Examples of exothermic reaction 

1. Reaction of calcium oxide with water

Calcium oxide + water —> calcium hydroxide + heat

CaO + H₂O —> Ca(OH)₂ + heat

2. Burning of natural gas

Methane + oxygen—> carbon dioxide + water + heat

CH₄ + 2O₂ —> CO₂ + 2H₂O + heat

3. Respiration

Respiration is an exothermic reaction. Glucose produced during the digestion of food combines with oxygen in the cells of our body and produces heat energy.

C₆H₁₂O₆(glucose) + 6O₂ —> 6CO₂ + 6H₂O + energy 

ENDOTHERMIC REACTION 

A chemical reaction in which heat energy is absorbed is known as endothermic reaction.

A + B+ heat  —> C + D

Examples of endothermic reaction 

1. Decomposition of ferrous sulphate 

When ferrous sulphate is heated, it absorbs the heat and decomposes to ferric oxide, sulphur dioxide and sulphur trioxide 

2FeSO₄ + heat —> Fe₂O₃ + SO₂ + SO₃

2. Decomposition of calcium carbonate 

Calcium carbonate also known as limestone when heated decomposes to calcium oxide (quick lime) and carbon dioxide 

CaCO₃ + heat —> CaO (quick lime) + CO₂