2026 Form 3 Chemistry Mid Term 2 Exam with Marking Scheme

This paper covers the following topics:

• Periodic table — electron arrangements, compound formulae, ionisation energy, atomic radius, and reactivity trends
• Noble gases — group identification and uses
• Ionic vs. covalent bonding in chlorides
• Solvay process — flowchart interpretation, raw materials, recycled substances, and reaction equations
• Carbon dioxide — uses as a fire extinguisher and laboratory preparation
• Graham’s law of diffusion — calculations comparing rates of diffusion of chlorine and hydrogen sulphide
• Charles’s law — table completion, graph plotting, extrapolation, and volume calculations
• Fractional distillation — apparatus identification and function (ethanol and water separation)
• Stoichiometry — mole calculations, percentage impurity in sodium carbonate, and carbon dioxide yield
• Avogadro’s law — statement and application to the reaction of sulphur dioxide and oxygen

• Number of Questions: 7 questions (Questions 1–7)
• Structure: All questions compulsory; answer all in spaces provided