Crystallisation | Exit Quiz | Oak National Academy

What is a saturated solution?

• A solution that can dissolve more solute.

• A solution where no more solute can dissolve.

• A solution that has evaporated completely.

• A solution mixed with an insoluble solid.

• A solution that changes colour with more solute.

Answer explanation

A saturated solution is one in which no more solute can dissolve at a given temperature. It's at its maximum capacity.

What happens during crystallisation?

• The solute evaporates leaving the solvent.

• The solvent dissolves more solute to form crystals.

• Solid crystals form by removing the solvent.

• The temperature of the solution decreases.

• The solvent turns into a solid.

Answer explanation

Crystallisation forms solid crystals from a solution by the continued removal of the solvent.

What does the term 'soluble' mean?

• Changes the colour of a solvent.

• Dissolves in a liquid.

• Increases the temperature of a solution.

• Forms a gas when mixed with a liquid.

Answer explanation

'Soluble' means that a substance can dissolve in a liquid, making it a part of the solution.

True or false? If a substance is soluble in one solvent, it is soluble in all solvents.

• True

• False

Answer explanation

Just because a substance is soluble in one solvent, does not make it soluble in all solvents. In fact, there are hundreds of commonly used solvents due to the fact substances have different solubilities.

Which of these are true statements about the differences between boiling and evaporation?

• Boiling occurs at the boiling point, evaporation happens below this temperature.

• Boiling forms crystals, evaporation does not.

• Boiling happens throughout the liquid, evaporation occurs only on the surface.

• Evaporation produces bubbles of gas, boiling does not.

• Evaporation results in crystal formation, boiling does not.

Answer explanation

Boiling occurs throughout the liquid at a specific temperature, forming gas bubbles, while evaporation happens only at the surface at any temperature below the boiling point, and above the melting point.

In a crystallisation process, the loss of the ___ leads to crystal formation.

Answer explanation

The loss of the solvent during crystallisation leads to the formation of crystals.