Ultimate Revision Guide: Master IGCSE Chemistry (0620) Formulas
Preparing for the Cambridge IGCSE Chemistry (0620) exam requires a strong grasp of both theoretical concepts and quantitative calculations. While Cambridge provides a standard Periodic Table in Paper 2, Paper 4, and Paper 6, no formula sheet is provided during the exam. This means students must memorise all key quantitative formulas and apply them accurately under timed conditions.
Essential IGCSE Chemistry Equations Quick Reference
| Topic | Key Formula | Units & Variables |
|---|---|---|
| Moles & Mass | Moles = Mass ÷ Mr |
Mass (g), Mr = Molar Mass (g/mol) |
| Concentration | c = n ÷ V |
c (mol/dm³), n (moles), V (volume in dm³) |
| Gas Volume (RTP) | Volume = Moles × 24 |
Volume (dm³) at Room Temperature & Pressure |
| Percentage Yield | (Actual Yield ÷ Theoretical) × 100 |
Expressed as a percentage (%) |
| Enthalpy Change (ΔH) | ΔH = Bonds Broken - Bonds Formed |
Energy in kJ/mol (Positive = Endothermic, Negative = Exothermic) |
Top Exam Strategies for Paper 2 (MCQ) & Paper 4 (Extended)
- Unit Conversions are Critical: Always check if volumes are given in cm³ or dm³. Remember to divide cm³ by 1000 to convert to dm³ before calculating concentrations.
- Master Organic Functional Groups: Ensure you can draw and recognize general formulas for Alkanes (CnH2n+2), Alkenes (CnH2n), Alcohols (CnH2n+1OH), and Carboxylic Acids (CnH2n+1COOH).
- Predict Electrolysis Products: For molten salts, metal forms at the cathode and non-metal at the anode. For aqueous solutions, remember hydrogen gas is evolved at the cathode unless a less reactive metal (like Copper) is present.
Frequently Asked Questions (FAQ)
A: No. External revision notes and formula sheets are strictly prohibited in CAIE examination rooms. Use this cheat sheet for active recall revision, flashcard creation, and past paper practice.
A: Yes. It covers all modern core and extended topics specified in the updated Cambridge IGCSE Chemistry 0620 syllabus.
A: Divide the percentage or mass of each element by its relative atomic mass (Ar), then find the simplest whole-number ratio between the resulting mole numbers.