Give two examples in case which brings about chemical action due to close contact.
A chemical reaction occurs when two substances are brought to close contact.
Example-
Give two example in case which brings about chemical action due to heat
Give two example in case of chemical action due to light.
(a) What is a physical change ? Give two examples of physical changes.
(b) What is chemical change ? Give two examples of chemical changes.
Give two examples to prove that heat energy brings about a chemical change.