About Experimental techniques and chemical analysis in O Level Chemistry
Experimental techniques and chemical analysis is one of the 12 main topics in our O Level Chemistry (Cambridge (CAIE) 5070) question bank, and about 15% of its real questions come from it. Tayyari Karo has 93 real questions on this topic from 2021 to 2026, from Paper 1, Paper 2, Paper 3, Paper 4; 42 are multiple choice and marked instantly, and the rest are structured questions with a model answer. By difficulty: 71 medium, 12 easy, 10 hard.
Work through the questions below, then open the explanation for each one. Redo the ones you missed a few days later.
Try 6 real questions
These are real past-paper questions. Think of your answer first, then open the explanation.
May/June 2026 · Paper 1 · Experimental techniques and chemical analysis
A gas occupies a volume of 2.0 dm3 at room temperature and pressure.
Which changes in the conditions would both decrease the volume occupied by the gas?
- temperature decreased, pressure decreased
- temperature increased, pressure decreased
- temperature decreased, pressure increased
- temperature increased, pressure increased
Show answer and explanation
Answer: C. temperature decreased, pressure increased
Decreasing the temperature slows the particles and increasing the pressure squeezes them closer, so both reduce the volume.
May/June 2025 · Paper 1 · Experimental techniques and chemical analysis
Add NaOH, warm, NH3?
- NH4+
- CO3 2-
- SO4 2-
- Cl-
Show answer and explanation
Answer: A. NH4+
Ammonium.
May/June 2024 · Paper 1 · Experimental techniques and chemical analysis
Add Ba(NO3)2; white ppt?
- carbonate
- sulfate
- chloride
- nitrate
Show answer and explanation
Answer: B. sulfate
BaSO4.
May/June 2023 · Paper 1 · Experimental techniques and chemical analysis
Add BaCl₂; white ppt insoluble in acid =
- carbonate
- sulfate
- chloride
- nitrate
Show answer and explanation
Answer: B. sulfate
BaSO₄.
May/June 2022 · Paper 1 · Experimental techniques and chemical analysis
Add AgNO₃; yellow precipitate. Ion?
- chloride
- bromide
- iodide
- nitrate
Show answer and explanation
Answer: C. iodide
AgI is yellow.
May/June 2021 · Paper 1 · Experimental techniques and chemical analysis
Which sequence separates a pure, dry sample of hydrated copper(II) sulfate from a mixture with calcium carbonate?
- dissolve in water then distillation then crystallisation
- dissolve in water then filtration then crystallisation
- distillation then crystallisation then heating
- fractional distillation then filtration then heating
Show answer and explanation
Answer: B. dissolve in water then filtration then crystallisation
Dissolve, filter off insoluble CaCO₃, crystallise CuSO₄.
