Starter quiz
- True or false? Solids that do not dissolve in a liquid are called insoluble.
- True ✓
- False
- What is the process of changing a liquid into a vapour (gas) called?
- 'evaporation' ✓
- True or false? When a solution is heated, the solvent evaporates more slowly.
- True
- False ✓
- Which properties below would be helpful in separating a mixture of substances?
- Smell of the substances.
- Boiling points of the substances. ✓
- Colour of the substances.
- Solubility of the substances. ✓
-
- True or false? All liquids have the same boiling point of 100℃.
- True
- False ✓
- In a mixture of two liquids with very different densities, the less dense liquid will ...
- float on top ✓
- sink to the bottom
- mix with the other liquid
-
Exit quiz
- What is the main purpose of using a 'separating funnel' in the lab?
- To measure the volume of a liquid.
- To heat substances.
- To mix two liquids.
- To separate immiscible liquids. ✓
-
- True or false? Decanting is effective for separating liquids with similar densities.
- True
- False ✓
- If two liquids can mix completely together to form one layer, they are said to be ...
- 'miscible' ✓
- True or false? A separating funnel can be used to separate two liquids that are miscible.
- True
- False ✓
- Match the keywords with their correct definition.
- density⇔Measurement of mass per unit volume. ✓
- immiscible⇔Liquids that are not soluble in another liquid. ✓
- miscible⇔Liquids that dissolve in another liquid. ✓
- decanting⇔Process of pouring off the top layer in a mixture of liquids ✓
- solution⇔A mixture comprised of a solute dissolved in a solvent. ✓
- Which of the following techniques should be used to separate miscible liquids?
- Filtering, to collect the solute.
- Heating, as the liquids have different boiling points. ✓
- Decanting, to separate the layers.
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Worksheet
Presentation
Video
Lesson Details
Key learning points
- Immiscible liquids do not mix and if allowed to settle, one will float above the other.
- Immiscible liquids can be separated by decanting or using a separating funnel.
- If left, miscible liquids do not separate into layers.
- The boiling points of liquids can be used to separate miscible liquids by changing states.
Common misconception
If a substance cannot be seen, it has disappeared and is no longer present.
Remind pupils of work regarding evaporation and use particle models to describe / explain what a solution of two liquids is like.
Keywords
Density - Density is a measurement of mass per unit volume; how tightly packed a substance's particles are in a particular space.
Boiling point - The boiling point of a substance is the temperature at which it changes from a liquid state to a gas state.
Immiscible - Liquids that are not soluble in another liquid are described as immiscible in that liquid.
Miscible - Liquids that dissolve in another liquid are described as miscible in that liquid.
Decanting - Decanting is a process of pouring off the top layer in a mixture of immiscible liquids, or a liquid and insoluble solid.