Formulae, Stoichiometry and the Mole Concept

(a) state the symbols of the elements and formulae of the compounds mentioned in the syllabus


(b) deduce the formulae of simple compounds from the relative numbers of atoms present and vice versa


(c) deduce the formulae of ionic compounds from the charges on the ions present and vice versa


(d) interpret chemical equations with state symbols


(e) construct chemical equations, with state symbols, including ionic equations


(f) define relative atomic mass, Ar


(g) define relative molecular mass, Mr, and calculate relative molecular mass (and relative formula mass) as the sum of relative atomic masses


(h) calculate the percentage mass of an element in a compound when given appropriate information


(i) calculate empirical and molecular formulae from relevant data


(j) calculate stoichiometric reacting masses and volumes of gases (one mole of gas occupies 24 dm3 at room temperature and pressure); calculations involving the idea of limiting reactants may be set (Knowledge of the gas laws and the calculations of gaseous volumes at different temperatures and pressures are not required.)


(k) apply the concept of solution concentration (in mol / dm3 or g / dm3) to process the results of volumetric experiments and to solve simple problems (Appropriate guidance will be provided where unfamiliar reactions are involved.)


(l) calculate % yield and % purity.