1. Relative atomic mass: average mass of element’s atom compared to 1/12 of 12C atom
Relative molecular mass: average mass of molecule compared to 1/12 of 12C molecule
For 1 mole
grams
2. Mole & Avogadro constant
Mass of particle g = Mr / Avogadro
Particles = moles x Avogadro
1 mole = 6.022 x 1023 particles
Particles = electrons / atoms / molecules / ions
Moles mol = mass g
Mr or M g mol-1
Moles mol = concentration mol dm-3 x volume dm3
3. Ideal gas equation: pV = nRT
p: Pa
V: m3 cm3 → dm3 → m3 ÷ 1000
n: moles
R: 8.31 J K-1 mol-1
T: K K = ˚C + 273
4. Empirical & molecular formula
Empirical formula: simplest integer ratio of atoms of each element in a compound
Molecular formula: actual number of atoms of each element in a compound
Empirical formula
Find moles from mass (or percentage)
Divide all moles by smallest moles
Find ratio
Relative molecular mass: average mass of molecule compared to 1/12 of 12C molecule
For 1 mole
grams
2. Mole & Avogadro constant
Mass of particle g = Mr / Avogadro
Particles = moles x Avogadro
1 mole = 6.022 x 1023 particles
Particles = electrons / atoms / molecules / ions
Moles mol = mass g
Mr or M g mol-1
Moles mol = concentration mol dm-3 x volume dm3
3. Ideal gas equation: pV = nRT
p: Pa
V: m3 cm3 → dm3 → m3 ÷ 1000
n: moles
R: 8.31 J K-1 mol-1
T: K K = ˚C + 273
4. Empirical & molecular formula
Empirical formula: simplest integer ratio of atoms of each element in a compound
Molecular formula: actual number of atoms of each element in a compound
Empirical formula
Find moles from mass (or percentage)
Divide all moles by smallest moles
Find ratio
