Page 68 - Science Class 06

In addi on, physical changes do not lead to v Emission of heat (exothermic reac on)
the forma on of new substances. Physical as a result of a chemical change
changes may or may not be reversible. v Absorp on of heat (endothermic

Examples of Physical Changes reac on) as a result of a chemical

v Breaking/Crushing of any object change

v Expansion of metal on hea ng v Emission of light as a result of a
chemical change
v Dissolving sugar or salt (solute) in water
(solvent) as a result, a solu on is formed v Produc on of sound as a result of a
chemical change
v Solidifica on of molten metal on

cooling v Change or emission of odour as a result
of a chemical change
v Shredding paper
v Emission of gas as a result of a chemical
change and so on.

Examples of Chemical Changes

v Rus ng of iron
v Souring of milk

v Ripening of fruits
Chemical Changes
v Diges on of food
One or more substances, at a me, react
with one another or substances which are v Burs ng of crackers
readily available in the environment. This
consequently leads to the forma on of a
new substance(s). The forma on of the new
substance can also be accompanied by one

or more of the following:

How physical and chemical changes are different?

Physical Changes Chemical Changes

1. A physical change is a temporary 1. A chemical change is a permanent
change. change.

2. In physical change no new substance is 2. A c h e m i ca l c h a n ge i s a l ways
formed. accompanied by one or more new
substance.

3. It does not result in any new substance 3. It gives result in a new substance with
with new proper es during the change. new proper es during the change.

68 Science-6