Question

What is the difference between element and a substance?
Is element a pure substance?

Or,

They both are same?

Answer 1

A Substance

is any matter, any material which has mass and occupies space. As far as a specific substance, a material has a specific constitution.

An Element

is a pure substance which cannot be broken down into (or synthesized by) other substances.

For example, water is a substance, but water itself is the result of the union of two other elements, hydrogen and oxygen.

And Yes, in chemistry a pure substance means either an element or a compound. Thus, hydrogen, oxygen, sodium, iron, copper etc. are pure substances; and so are compounds such as water, sugar, ammonia, sodium chloride, methane, ethanol etc. A compound is composed of two or more elements combined in a fixed ratio by mass.