C1.3 Chemical Calculations (copy)

Relative atomic mass

is the weighted mean mass of an atom of an element compared to 1/12th of a carbon-12 atom.

Relative isotopic mass

is the mass of an atom of an isotope of the element compared to 1/12th of a carbon-12 atom

Stage 1 of a mass spectrometer

vapourisation

Stage 2 of a mass spectrometer

ionisation

Stage 3 of a mass spectrometer

acceleration

Stage 4 of a mass spectrometer

deflection

Stage 5 of a mass spectrometer

detection

Empirical formula

the simplest ratio of atoms in a compound

Molecular formula

the actual number and types of atom in a molecule

n = (solids/liquids)

m/M_r

n = (solutions)

Concentration x Volume

n = (gases)

Volume/molar volume

Ideal gas equation

PV = nRT

Units of V in ideal gas equation

metres cubed (m³)

Units of temperature in ideal gas equation

Kelvin (K)

Units of pressure in ideal gas equation

Pascals (Pa)

Molar volume at rtp

24dm³

Molar volume at stp

22.4dm³

Atom economy =

mass of useful product / total mass of reactants

Percentage yield =

actual yield / theoretical yield x 100

Avogadro’s Number =

6.02 x 10²³ particles/mol

Percentage uncertainty in a measurement =

((error per measurement x number of measurements)/value) x 100