Question

A sample of solid potassium chlorate is heated strongly for 30 minutes. The sample melts, and bubbles of gas escape during the heating. Upon cooling the heated sample becomes solid. The solid is white in color before and after heating. A sample of unheated solid is dissolved in water and 10 drops of silver nitrate are added. Nothing happens. A sample of the heated solid is also dissolved in water and treated with 10 drops of silver nitrate. The solution becomes very cloudy. What classification should be given to the change that occurs when potassium chlorate is heated?
A) physical
B) chemical
C) can't be determined

Answer 1

Answer : The correct option is, (B) chemical change

Explanation :

Chemical change : It is a change in which a new substance is formed when the changes occurs in the chemical composition. It is usually an irreversible reaction.

Physical change : It is a change in which the shape and the size of a substance changes. There is no change in the composition of the substance. It is usually a reversible reaction.

when potassium chlorate is heated then changes occurs in the chemical composition of the potassium chlorate and the new substance will be formed. So, the chemical change occurs when potassium chlorate is heated.

when potassium chlorate is strongly heated then potassium chloride and oxygen gas is formed.

Hence, the correct option is, (B) chemical change

Answer 2

This was clear chemical reaction. The Potassium Chlorate reacted with Oxygen in a combustion reaction to change the chemical structure so that it was able to react with Silver Nitrate.