Question

define exothermic and endothermic reactions. give two examples in each case

Answer 1

Answer:

Exothermic Reactions

Endothermic Reaction Exothermic Reaction

Energy in the form of heat Energy is released as heat, electricity, light or sound.

Melting ice, evaporation, cooking, gas molecules, photosynthesis are few examples Rusting iron, settling, chemical bonds, explosions, nuclear fission are a few examples

Answer 2

Exothermic reaction :

When energy is released in the form of heat during the reaction, it is called an exothermic reaction. The heat evolved is shown by a plus sign on the right-hand side of the equation.

For example :

$\sf N_{2} (g) + 3 H_{2} (g) \longrightarrow 2NH_{3} (g) + 92 kJ$

Endothermic reaction :

When energy is absorbed as heat during a reaction it is called an endothermic reaction the heat absorbed is shown by a plus sign on the left hand side of the equation or with the negative side on right hand side.

For example :

$\sf N_{2} (g) + O_{2} (g) + 180 kJ \longrightarrow 2NO (g)$

⠀ ⠀⠀ ⠀ ⠀⠀ OR

$\sf N_{2} (g) + O_{2} (g) \longrightarrow 2NO (g) - 180 kJ$