Mole Calculations

Moles from Mass

n = m / MUnit: mol
What it means: Moles = mass in grams divided by molar mass.
Example: 4g of NaOH (M=40): n = 0.1 mol

Moles of Gas at STP

n = V / 22.4
What it means: At STP, 1 mole of any gas occupies 22.4 litres.
Example: 11.2 litres of CO2: n = 0.5 mol

Concentration

c = n / VUnit: mol/L
What it means: Concentration = moles divided by volume in litres.
Example: 0.5 mol in 2L: c = 0.25 mol/L