How to work out moles in chemistry?
n = m / Mr n = number of moles , m = mass of substance (grams) , Mr = relative molecular mass (this also applies for relative atomic mass Ar when you’re talking about an element rather than a compound) e.g. 24g of Carbon Carbon has an Ar of 12 n = 24 / 12 = 2 moles sometimes mole is shortened to mol Another mole equation is n = cV where c = the concentration of the substance in mol / litre and V = the volume of the whole solution e.g. 0.2 litres of hydrochloric acid at a concentration of 0.1 mol/L n = cV n = 0.1 * 0.2 = 0.02 moles Also any gas at room temperature and 1 atmoshere pressure: n = V / 24,000 (cm^3) or n = V / 24 (L) e.g. 0.96L of gas X (remember 1L = 1,000cm^3) n = 0.96 / 24 = 0.04 moles You should listen more in class.
