Question

Diffrentiate between endothermic and exothermic reactions with example ?

Answer 1

Meaning

• Chemical reactions involving the use of energy at the time of dissociation to form a new chemical bond is known as the endothermic reaction.

• Chemical reactions where the energy is released or evolved in the form of heat is known as the exothermic reaction.  

Energy

• The endothermic process requires energy in the form of heat.
• The exothermic process evolves or releases in the form of heat.

Enthalpy (ΔH)

• ΔH is positive, as heat is absorbed.(endothermic)
• ΔH is negative, as heat is evolved. (exothermic)

Examples

• 1. Conversion of ice into water vapour through boiling, melting or evaporation.

2. Breaking of the gas molecules.

3. Production of anhydrous salt from hydrate.(endothermic)

• 1. Formation of ice from water.

2. Burning of coal (combustion).

3. The reaction between water and the strong acid. (exothermic)

Answer 2

Exothermic reactions are those reactions in which heat is released along with the products.

CaO + H2O ⇒ Ca(OH)2 + heat

When energy gets absorbed during a reaction , the reaction is said to be endothermic.

Photosynthesis is a good example of endothermic reactions in which light energy from the sun is absorbed.

6CO2 + 6H20 + sunlight ⇒ C6H12O6 + 6O2