2 Amount of substance

Question 1

Define relative atomic mass (Ar)

Answer 1

The weighted average mass of all isotopes relative to 1/12th the mass of an atom of carbon-12

Question 2

Define relative molecular mass (Mr)

Answer 2

The mass of a molecule of the compound relative to 1/12th the mass of an atom of carbon-12

Question 3

Define relative formula mass

Answer 3

The mass of one formula unit of an ionic compound relative to 1/12th the mass of an atom of carbon-12