Change is the law of nature and occur in our everyday life, at all times & in all places. Differentiate between the following changes with a suitable example.
a) Desirable & undesirable change
b) Periodic & non-periodic change
c) Slow & fast change
d) Natural & man-made change
e)Reversible & irreversible change

Differentiate between a physical change & a chemical change with reference to-
a) Nature of change i.e temporary & reversible or permanent & irreversible.
b) Formation of products
c) Energy change taking place during the respective change.

Give three reasons why melting of wax, is considered a physical change while burning of a candle, a chemical change.

State the observations seen, when milk in a dish is kept aside for a few hours or more. Is the change which occurs-a physical change or a chemical change. Give reasons.

State what is meant by the term-interconversion of matter. Is interconversion of matter a physical change or a chemical change.