IP Chemistry Upper Sec 04: Chemical Calculations

These notes align with SEAB GCE O-Level Chemistry (6092) content used in IP programmes (exams from 2026).

Status: SEAB O-Level Chemistry 6092 syllabus (exams from 2026) checked 2025-11-30 - scope unchanged; remains the reference for this note.

What you must know

• Build correct formulae from valencies/charges (cross-multiply) and balance equations with state symbols; extract ionic equations by removing spectators.
• Mole concept: $n = \frac{m}{M_r}$; Ar/Mr vs empirical vs molecular formula; percentage composition from formula.
• Reacting masses and gas volumes: at r.t.p. $24~\text{dm}^{3}$