IM Chemistry: Core Syllabus Content
This domain covers the whole Intermediate Matriculation Chemistry syllabus: atomic structure and bonding, amounts of substance, energetics, rates and equilibria, redox and electrochemistry, organic functional groups and their reactions, and practical analysis. The examination rewards precise definitions, correctly balanced equations with state symbols, and calculations carried through from the equation to a final answer with units and sensible significant figures. Accuracy of terminology matters as much as the number at the end.
Core rules and concepts
- Amounts of substance: n = m/M, n = cV with V in dm³, and n = V/24.0 dm³ for a gas at room temperature and pressure. The mole ratio from the balanced equation is the only link between reactants.
- Structure and bonding: ionic lattices melt high and conduct when molten; simple molecular substances have weak intermolecular forces; giant covalent solids (diamond, graphite, SiO₂) are exceptions to simple rules. VSEPR gives 109.5° for four pairs, 120° for three, 180° for two.
- Energetics: ΔH = Σ(bonds broken) − Σ(bonds formed); Hess cycles for enthalpy of formation and combustion; ΔG = ΔH − TΔS decides feasibility.
- Equilibria: Kc and Kp depend only on temperature; Le Chatelier predicts the direction of shift. For a weak acid, [H⁺] = √(Ka × c) and pH = ½(pKa − log c).
- Organic tests and mechanisms: Br₂ water decolourised by alkenes; 2,4-dinitrophenylhydrazine for carbonyls; Fehling's and Tollens' distinguish aldehydes. Know SN1/SN2, electrophilic addition, nucleophilic addition and esterification, plus IUPAC naming with lowest locants.
Worked example
25.0 cm³ of 0.100 mol dm⁻³ NaOH is neutralised by 0.0500 mol dm⁻³ H₂SO₄. What volume is needed? 2NaOH + H₂SO₄ → Na₂SO₄ + 2H₂O. n(NaOH) = 0.100 × 0.0250 = 2.50 × 10⁻³ mol. The ratio is 2:1, so n(H₂SO₄) = 1.25 × 10⁻³ mol. Then V = n/c = 1.25 × 10⁻³ ÷ 0.0500 = 0.0250 dm³ = 25.0 cm³, quoted to three significant figures to match the data.
Traps that cost marks
Using cm³ directly in cV; forgetting to dilute when two solutions are mixed; ignoring the limiting reagent; applying bond enthalpies to reactions in aqueous solution where hydration enthalpies dominate; omitting state symbols in enthalpy equations; writing "equilibrium shifts" without stating left or right; and rounding intermediate values too early.