What does one mean by exothermic and endothermic reactions? Give examples.

 

Answer

A chemical reaction in which a large amount of heat / energy is produced along with the products is called exothermic reaction.

 

For example, 

Calcium Oxide (Quick Lime) reacts with Water to produce Calcium Hydroxide (Slaked Lime) and Heat

CaO(s) + H 2 O(l) → Ca(OH) 2 (aq) + Heat

 

Since heat is produced / released in this reaction, this reaction is called an exothermic reaction

 

A chemical reaction in which a large amount of heat / energy is absorbed is called endothermic reaction.

 

For example, 

On heating of Calcium Carbonate (limestone) 

It decomposes into Calcium Oxide (Quick Lime) + Carbon Dioxide

 

CaCO 3 (s)     →     CaO(s) + CO 2 (g)

                        Heat

 

Since heat is absorbed in this reaction, this reaction is called an endothermic reaction.

  1. Class 10
  2. Chapter 1 Class 10 - Chemical Reactions and Equations (Term 1)

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CA Maninder Singh
CA Maninder Singh is a Chartered Accountant for the past 11 years and a teacher from the past 11 years. He teaches Science, Accounts and English at Teachoo