Explain the different types of chemical reactions, with one balanced example each.

1. 1 · Open in one line. A chemical reaction changes reactants into new products. Reactions are grouped by how the atoms rearrange.
2. 2 · Combination. Two or more substances join to form one product: 2Mg + O₂ → 2MgO.
3. 3 · Decomposition. One compound splits into simpler substances by heat (CaCO₃ → CaO + CO₂), electricity (2H₂O → 2H₂ + O₂) or light (2AgBr → 2Ag + Br₂).
4. 4 · Single displacement. A more reactive element displaces a less reactive one: Zn + CuSO₄ → ZnSO₄ + Cu.
5. 5 · Double displacement. Two compounds swap ions: AgNO₃ + NaCl → AgCl + NaNO₃ (precipitation); NaOH + HCl → NaCl + H₂O (neutralisation).
6. 6 · Combustion. A substance burns in oxygen giving heat and light: CH₄ + 2O₂ → CO₂ + 2H₂O.
7. 7 · Real-life link. LPG burning in the stove is combustion; quicklime and water for whitewash is combination.
8. 8 · Close in one line. Thus every reaction can be placed in a type by seeing what joins, splits, swaps or burns.

Scoring tip: Balance every equation and write the general form (A + B → AB) beside each type. That alone earns part marks.