Question

Three example of endothermic reaction with chemical equation.

Answer 1

Photosynthesis

This process includes chlorophyll in green plants which converts carbon dioxide and water into oxygen and glucose. Here, the energy is provided by the Sunlight energy. It is an important reaction for the plant’s life.

        6CO2+6H2O ->C6H12O6+6O2.

2. In a test tube, when a small quantity of ammonium chloride (NH4Cl) is dissolved in water, the tube becomes colder. Heat is absorbed from the surroundings during the chemical reaction.

                                      NH4Cl(s) + H2O(l) →→ NH4Cl(aq) – heat

3. When crystals of sodium thiosulphate (Na2S2O3.5H2O), also known as hypo gets dissolved in water, a cooling effect takes place.

                                   Na2S2O3.5H2O + H2O →→ Ns2SO3(aq) – heat

Answer 2

2Cu+O2 ---- 2Cuo
CuO+H2 ---- Cu+H2O
CuO+H2 --- Cu+ H2O