Stoichiometry (CIE Topic 3)

Word Equation

A method of showing a chemical process using the names of reactants and products

Chemical Equation

A method of showing a chemical process, both products and reactants using molecular formulae

Compound Ion

A group of atoms bonded together in such a way that overall they have a charge

Molecular formulae

Number and type of atoms in a molecule

Carbonate

CO₃²⁻

Nitrate

NO₃⁻

Sulphate

SO₄²⁻

Phosphate

PO₄³⁻

Hydroxide

OH⁻

Ammonium

NH₄⁺

Ammonia

NH₃

Carbon dioxide

CO₂

Relative molecular mass

the sum of relative atomic masses of atoms in a molecule

Relative formula mass

the sum of atomic masses of elements listed in a formula

Avagadro’s Number

the number of particles in one mole, approximately 6 x 10²³

1 mole

is the amount of substance that contains the same number of entities as there are atoms in 12 g of carbon-12.

Molar gas volume (Vm)

is the volume occupied by one mole of gas at room temperature and pressure, approximately 24 dm³.

mole (solids/liquids) =

mass/RAM

mole (solutions) =

concentration x volume

mole (gases) =

volume/Vmmolar gas volume

Empirical formula

simplest ratio of atoms in a compound

percentage yield =

Actual/Theoretical x 100

Atom economy

mass of useful product/total mass of reactants x 100