Definitions - Amount of Substance

Question 1

Concentration

Answer 1

The moles of solute dissolved per 1 dm^3 (1000cm^3) of solution

Question 2

Molar mass

Answer 2

The mass per mole of a substance (g mol^-1)

Question 3

Molar gas volume

Answer 3

The volume that 1 mole of a gas occupies at room temperature and pressure (24dm3 or 24000cm3

Question 4

Relative atomic mass

Answer 4

The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12

Question 5

Relative formula mass

Answer 5

The weighted mean mass of a formula unit compared with 1/12 of the mass of an atom of carbon-12

Question 6

Relative isotopic mass

Answer 6

The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12

Question 7

Relative molecular mass

Answer 7

The weighted mean mass of a molecule compared with 1/12 of the mass of an atom of carbon-12

Question 8

Standard solution

Answer 8

A solution of known concentration

Question 9

The Avogadro Constant (NA)

Answer 9

The number of atoms per mole of the carbon-12 isotope
(6.02 x 1023 mol-1)