IB Chemistry Assessment: Filtration & Recrystallization

Which of the following is a key difference between filtration and recrystallization processes?

• Filtration separates solids from liquids; recrystallization purifies solid compounds.

• Recrystallization separates solids from liquids; filtration purifies solid compounds.

• Both processes involve separation of liquids.

• Both processes require heating to separate components.

During recrystallization, why is a solvent often chosen that dissolves the solute at high temperatures but not at low temperatures?

• To ensure the solute remains dissolved.

• To promote rapid evaporation.

• To allow impurities to crystallize.

• To enable selective crystallization of the solute upon cooling.

Which type of mixture is typically separated using filtration?

• Immiscible liquids

• A solution of sugar in water

• A suspension of sand in water

• A homogeneous mixture of ethanol and water

Why is it important to use hot solvent in the recrystallization process?

• To dissolve impurities.

• To increase the solubility of the solute.

• To evaporate the solvent quickly.

• To ensure the solute does not crystallize too early.

In vacuum filtration, what is the role of reduced pressure?

• To speed up the drying process.

• To increase the solubility of the solute.

• To prevent the solvent from evaporating.

• To decrease the temperature of the system.

Which property of the solvent is crucial for a successful recrystallization?

• High boiling point

• Low polarity

• Different solubility at different temperatures

• Miscibility with water

Which apparatus is most commonly used for filtration?

• Separating funnel

• Buchner funnel

• Distillation flask

• Conical flask

In recrystallization, which of the following could indicate that the solvent is not suitable?

• The solute dissolves at high temperatures.

• Impurities remain in the solvent.

• The solute does not recrystallize upon cooling.

• The solvent evaporates too slowly.

What is the primary purpose of recrystallization?

• To separate liquids from solids.

• To purify a solid by removing impurities.

• To dissolve substances in a solvent.

• To create a precipitate from a solution.

Which of the following describes a good filtration method for collecting large solid particles from a liquid?

• Simple filtration

• Paper chromatography

• Fractional distillation

• Centrifugation