define endothermic and exothermic change
 

Asked by arajeevshashank | 7th Nov, 2017, 08:41: PM

Expert Answer:

Exothermic reactions

A chemical reaction in which heat is given out is called an exothermic reaction. It causes a rise in temperature.

Respiration, rusting, burning of coal, petrol and kerosene are some common examples of exothermic reactions.

Examples:

A lot of heat is produced when carbon burns in oxygen to form carbon dioxide.

straight C space plus space straight O subscript 2 space space rightwards arrow space CO subscript 2

 

Endothermic reactions

A chemical reaction in which heat is absorbed is called an endothermic reaction.

It causes a fall in temperature.

Examples:

When nitrogen and oxygen are heated to a temperature of about 3000°C, nitric oxide gas is formed. This is an endothermic reaction.

straight N subscript 2 space plus space straight O subscript 2 space end subscript space plus space Heat space rightwards arrow space 2 NO

Answered by Varsha | 8th Nov, 2017, 10:24: AM