Define Exothermic and Endothermic reaction. Give one example of each with balanced chemical equations. | web4study

Define Exothermic and Endothermic reaction. Give one example of each with balanced chemical equations.



EXOTHERMIC REACTIONS:

Exothermic Reaction is a reaction during which heat is given out the change in heat is represented by a negative sign.

EXAMPLE:

Combustion of coal in air produces C02 with the release of 393.7-kiloJoules of heat. When 1 mole of coal is burnt in 1 mole of Oz to produce 1 mole of CO2.

C + O2  -> COz H = -393.7 KJ/mol. 

 

ENDOTHERMIC REACTION:

Endothermic Reaction is the chemical change during which heat is absorbed or taken in from the surroundings. The container becomes cold.

Examples:

(i) Decomposition of Water (HzO) into Hydrogen Hz and Oxygen Oz on passing through water.

HzO -> Hz+ 1/2 O2

ΔH = + 286 K Joule/mole

(ii) Formation of Nitric Oxide (NO) by the combination of 1/2 mole N2 with 1/2 mole of O2

1/2 N2+1/2 O2 -> NO

ΔH = + 90.25 K.J/mol

 

 


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