Question

${Question}$

What is physical change and chemical change?​

Answer 1

Physical changes only change the appearance of a substance, not its chemical composition. Chemical changes cause a substance to change into an entirely substance with a new chemical formula. Chemical changes are also known as chemical reactions.

Answer 2

$\bold{\huge{\fbox{\color{purple}{Physical\: Change}}}}$

The change in which no new substance is formed is called a physical change. A change in the physical properties of a substance such as shape, size, colour and state of the matter is a physical change.

$\bold\red{Examples:-}$

Melting of ice, boiling of water, freezing of water, condensation, crystallisation and heating of metals till they become red hot, etc.

Characteristics of a physical change are as follows:-

☆ Physical changes are generally reversible.

☆ Physical changes are temporary in nature.

☆ No new substances are formed.

☆ Energy, in the form of heat, light and temperature is neither absorbed nor evolved.

☆ During a physical change only the physical properties of the substance changes.

$\bold{\huge{\fbox{\color{purple}{Chemical\: Change}}}}$

A chemical change occurs when two or more substances undergo a chemical reaction and are converted into one or more new substances with different sets of properties.

$\bold\red{Examples:-}$

Formation of rust on iron objects which are kept in the open for a long time, digestion of food, burning of magnesium, reaction between vinegar, ribbon and baking soda are some types of chemical changes.

Characteristics of a chemical change are as follows:-

☆ A chemical change is permanent in nature and is irreversible.

☆ A new substance is formed which has different properties.

☆ Heat or light may be emitted or absorbed during a chemical reaction.

☆ A chemical change occurs only under particular conditions.