CIE iGCSE Co-Ordinated Science C12.2 Acid-base titrations Exam Style Questions Paper 1
▶️ Answer/Explanation
Excess copper oxide is added so that all the sulfuric acid reacts, leaving unreacted solid copper oxide in the mixture.
Since copper oxide is insoluble, it can be separated from the aqueous copper sulfate solution by filtration, leaving the copper oxide as the residue.
Crystallisation would instead be used afterwards to obtain solid copper sulfate crystals from the filtrate.
✅ Answer: (D)
Since copper oxide is insoluble, it can be separated from the aqueous copper sulfate solution by filtration, leaving the copper oxide as the residue.
Crystallisation would instead be used afterwards to obtain solid copper sulfate crystals from the filtrate.
✅ Answer: (D)
▶️ Answer/Explanation
Hexane and octane are miscible liquids with different, relatively close boiling points, so fractional distillation is needed to separate them.
This apparatus uses a fractionating column to allow repeated evaporation and condensation, separating the liquids according to their boiling points.
✅ Answer: (D)
This apparatus uses a fractionating column to allow repeated evaporation and condensation, separating the liquids according to their boiling points.
✅ Answer: (D)
▶️ Answer/Explanation
Filtration is used first to remove the excess, unreacted insoluble magnesium oxide from the mixture.
The remaining magnesium chloride solution is then evaporated to concentrate it, allowing crystals to form on cooling.
✅ Answer: (B)
The remaining magnesium chloride solution is then evaporated to concentrate it, allowing crystals to form on cooling.
✅ Answer: (B)
▶️ Answer/Explanation
Filtration is used first to remove the insoluble impurity from the salt solution.
The filtrate (pure salt solution) is then evaporated/crystallised to obtain pure salt crystals.
✅ Answer: (C)
The filtrate (pure salt solution) is then evaporated/crystallised to obtain pure salt crystals.
✅ Answer: (C)
▶️ Answer/Explanation
The spot of ink must be drawn above the level of the solvent so that it is not washed straight off the paper.
The solvent must be in contact with the paper below the spot so that it rises up by capillary action.
Only diagram C shows the spot correctly positioned above the solvent level with the paper standing in the solvent.
✅ Answer: (C)
The solvent must be in contact with the paper below the spot so that it rises up by capillary action.
Only diagram C shows the spot correctly positioned above the solvent level with the paper standing in the solvent.
✅ Answer: (C)