CIE iGCSE Co-Ordinated Science C12.4 Separation and purification Exam Style Questions Paper 2
▶️ Answer/Explanation
An impure solid melts over a range of temperatures rather than at a sharp point. The graph should show a gradual increase in temperature during melting, not a flat horizontal line. Among the options, graph A shows this gradual slope, so it is correct.
✅ Answer: (A)
✅ Answer: (A)
▶️ Answer/Explanation
Filtration separates the insoluble solid chalk from the liquid, leaving a filtrate containing the dissolved salt and water.
Crystallisation is then used to separate the dissolved soluble salt from the water by evaporating the solvent.
✅ Answer: (D)
Crystallisation is then used to separate the dissolved soluble salt from the water by evaporating the solvent.
✅ Answer: (D)
▶️ Answer/Explanation
Filtration separates the insoluble impurity from the salt solution via \(\text{mixture} \rightarrow \text{residue} + \text{filtrate}\).
The filtrate is then evaporated/cooled through crystallisation to grow pure salt crystals from solution.
✅ Answer: (C)
The filtrate is then evaporated/cooled through crystallisation to grow pure salt crystals from solution.
✅ Answer: (C)
▶️ Answer/Explanation
Hexane and octane are miscible liquids with different boiling points, so they must be separated by fractional distillation.
This requires a fractionating column fitted above the flask, allowing vapours to separate as they condense at different heights — shown in apparatus D.
✅ Answer: (D)
This requires a fractionating column fitted above the flask, allowing vapours to separate as they condense at different heights — shown in apparatus D.
✅ Answer: (D)
▶️ Answer/Explanation
Filtration first separates the insoluble solid sulfur from the sodium chloride solution, since sulfur cannot pass through the filter paper.
The filtrate, a sodium chloride solution, is then heated to evaporate water until saturated, and cooled to allow crystals of sodium chloride to form — this is crystallisation.
Distillation and chromatography are not needed here, since the goal is to recover a dissolved solid, not to separate a liquid mixture or coloured substances.
✅ Answer: (D)
The filtrate, a sodium chloride solution, is then heated to evaporate water until saturated, and cooled to allow crystals of sodium chloride to form — this is crystallisation.
Distillation and chromatography are not needed here, since the goal is to recover a dissolved solid, not to separate a liquid mixture or coloured substances.
✅ Answer: (D)