Chemical calculations

Relative atomic mass (Ar)

The average mass of one atom of that element relative to 1/12 the mass of an atom of carbon-12.

Relative molecular mass (Mr)

The average mass of one molecule of that substance relative to 1/12 the mass of an atom of carbon-12.

Relative formula mass (Mr)

The average mass of one unit of that compound relative to 1/12 the mass of an atom of carbon-12. (same as molecular mass)

Percentage mass

[(number of atoms of that element in the formula x Ar of that element) / Mr of compound] x 100%

Mole

The amount of of substance that contains the same number of particles as the number of atoms in exactly 12g of carbon-12 isotope.

Avogrado’s constant

6.02×10²³

How to find mole (from no. of particles)

Number of particles / 6.02×10²³

Unit for molar mass

g/mol

How to find mole (from mass)

mass/molar mass

One mole of any gas occupies a volume of ___ at ____ _____ and _____

24dm³, room temperature, pressure

How to find mole (gas volume)

volume of gas in dm³ / 24dm³

Units for concentration

g/dm³ and mol/dm³

How to convert g/dm³ to mol/dm³

g/dm³ / molar mass

How to find mole (solution)

concentration (mol/dm³) / volume of solution