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HSC Chemistry Formula Sheet
Modules 5-8 | NSW NESA Syllabus 2025 | learncoretutoring.com
Module 5: Equilibrium and Acid Reactions
| Formula / Expression | Meaning | Notes |
|---|
| Keq = [products]coeff / [reactants]coeff | Equilibrium constant expression | Pure solids and liquids excluded; concentrations in mol/L |
| Ka = [H+][A–] / [HA] | Acid dissociation constant | Larger Ka = stronger acid |
| Kb = [BH+][OH–] / [B] | Base dissociation constant | Larger Kb = stronger base |
| Kw = Ka × Kb = 1.0 × 10-14 | Water dissociation constant (25°C) | Conjugate acid-base pair relationship |
| pH = -log10[H+] | pH definition | [H+] = 10-pH |
| pOH = -log10[OH–] | pOH definition | pH + pOH = 14 at 25°C |
| pKa = -log10(Ka) | pKa definition | pKa + pKb = 14 |
Module 6: Acid/Base Reactions
| Formula / Expression | Meaning | Notes |
|---|
| n = c × V | Moles = concentration × volume | V must be in litres |
| c1V1 = c2V2 | Dilution formula | Moles constant when diluting |
| n(acid) / n(base) = ratio from equation | Titration stoichiometry | Always write the balanced equation first |
| Indicator pH range: endpoint ≈ equivalence point | Indicator selection rule | Phenolphthalein: 8.2-10.0; Methyl orange: 3.1-4.4 |
Module 7: Organic Chemistry – Functional Groups
| Functional Group | Structure | IUPAC Suffix/Prefix |
|---|
| Alkane | C-C single bonds only | -ane |
| Alkene | C=C double bond | -ene |
| Alcohol | -OH (hydroxyl) | -ol |
| Aldehyde | -CHO (terminal C=O) | -al |
| Ketone | C=O (internal) | -one |
| Carboxylic acid | -COOH | -oic acid |
| Ester | -COO- | -yl -oate |
| Amine | -NH2 | -amine / amino- |
| Amide | -CONH2 | -amide |
Module 8: Applying Chemical Ideas
| Formula | Meaning | Variables |
|---|
| A = ε l c | Beer-Lambert Law | A=absorbance; ε=molar absorptivity; l=path length (cm); c=concentration (mol/L) |
| % by mass = (mass solute / mass solution) × 100 | Percentage composition | Both masses in same unit |
| ppm = mg/L = mg/kg | Parts per million (dilute aqueous) | Assumes solution density ≈ 1 g/mL |
| Gravimetric factor = M(analyte) / M(precipitate) | Gravimetric analysis conversion | Multiply precipitate mass by factor to get analyte mass |
