Elements are the ________ form of pure substances.

In a chemical reaction , the atoms of the reacting molecules or elements are _________ to form new molecules .

Give any two characters of a pure substance.

The substances taking part in a chemical reaction are called "_______", whereas the substances formed as a result of a chemical reaction are called "_________".

What is the boiling point of a pure substance ?

State true or false. If false, give the correct statement. Compounds and elements are pure substances.

Give the main difference between a pure substance and an impure substance.

d- block elements form ________ compounds.

Plastic bottles are formed from a chemical substance ………. .