Chemical Changes and Reactions – Notes
Physical and Chemical Changes – Physical and Chemical Changes
Change is all around us and happening constantly. Some changes are Physical and some are chemical.
Some changes affect only the physical properties of the substance that is undergoing change. Physical include things like shape, size, colour and state of matter. Physical changes are generally reversible.
No new substances are formed when a physical change takes place.
Some changes are the result of chemical reaction. These lead to the creation of new substances and generally cannot be reversed.
Chemical changes are sometimes accompanied by things like heat, sound, smell, formation of a gas, etc.
ICSE Class 9th Chemistry 2 - Chemical Changes and Reactions - Notes