Starter quiz
- Which process happens when a solid can be observed to 'disappear' in a liquid to make a solution?
- boiling
- condensing
- melting
- dissolving ✓
- evaporating
-
- When a process is able to go backwards, or be "undone", it is said to be ...
- 'reversible' ✓
- Match the word to the definition.
- Soluble⇔When a solid can dissolve in a liquid. ✓
- Insoluble⇔When a solid cannot dissolve in a liquid. ✓
- Solution⇔The mixture formed when a solid dissolves in a liquid. ✓
- Saturated⇔When no more solid can dissolve. ✓
- A volume of salt solution containing 0.50 g of salt was placed in a beaker and left for two weeks on the window sill, after which only crystals of salt remained. How much salt would be present?
- 0.00 g
- 0.25 g
- 0.40 g
- 0.50 g ✓
-
- Sugar was added to water at 60℃ until no more sugar could dissolve. The solution was left to cool. What would you expect to see and why?
- No change as the sugar would still be dissolved.
- No change as temperature does not affect the solubility of the sugar.
- Solid sugar would start to form as the water would evaporate.
- Solid sugar would start to form as it is less soluble at a lower temperature. ✓
-
- When a solution is left to evaporate, the solute left behind can form ...
- 'crystals' ✓
Exit quiz
- 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.
-
- 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.
-
- 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.
-
- True or false? If a substance is soluble in one solvent, it is soluble in all solvents.
- True
- False ✓
- 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.
-
- In a crystallisation process, the loss of the ______ leads to crystal formation.
- 'solvent' ✓
Worksheet
Loading worksheet ...
Presentation
Loading presentation ...
Video
Lesson Details
Key learning points
- Crystallisation is a technique that is used to separate a soluble solute from a solution.
- Crystallisation involves the formation of a saturated solution and temperature differences.
- Crystallisation results in the loss of the solvent to the surroundings.
Common misconception
Pupils sometimes use the terms evaporation and boiling interchangeably, but they are not the same.
Boiling: a liquid substance is heated and gas bubbles form. Evaporation: same, BUT only on the surface of the liquid, no bubbles form and the gas mixes with air.
Keywords
Saturated solution - A saturated solution is one in which no more solute can dissolve in the solvent at a given temperature.
Crystallisation - Crystallisation is a process that forms solid crystals from a saturated solution by continued removal of the solvent (e.g. evaporation).
Soluble - When a substance dissolves in a liquid, it is described as soluble in that liquid.
Solvent - A solvent is a liquid into which a solute dissolves.
+