Starter quiz
- Which picture shows an insoluble substance?
- Mass is measured in ...
- centimetres.
- millilitres.
- grams. ✓
- centimetres-cubed.
-
- Sugar dissolves in water, so sugar can be described as a ______ solid.
- 'soluble' ✓
- A ______ is a material formed from two or more substances which can be physically separated.
- 'mixture' ✓
Some students have been asked to describe this diagram using key terms. Who has used their key words correctly?
That shows a pure liquid.
I think that might be a liquid mixture.
I'm fairly certain this shows an impure solid.
I reckon that's a pure solid. ✓
- Melting is a reversible, physical change. Which of the following statements is also true about melting?
- Melting is what happens when a substance disappears.
- Melting occurs when solid particles become more regularly arranged.
- Melting is the process of a substance disappearing in a liquid.
- Melting occurs when solid particles become more irregularly arranged. ✓
-
Exit quiz
- What happens when a solute dissolves in a solvent?
- A chemical reaction occurs.
- A solution is formed. ✓
- The solvent evaporates.
- A precipitate is formed.
-
- What is a solvent in a solution?
- The substance being dissolved.
- The liquid that dissolves a substance. ✓
- The chemical that reacts.
- The solid part of a solution.
- The visible part of a solution.
-
- Which term describes a substance that does not dissolve in a solvent?
- 'insoluble' ✓
- Match the state symbol to its meaning.
- (s)⇔solid ✓
- (l)⇔liquid ✓
- (g)⇔gas ✓
- (aq)⇔dissolved in water ✓
- If a substance is highly soluble (has a high solubility) in water, it means it can ______ easily in water.
- 'dissolve' ✓
- Not everything is soluble in water. We can try and use a different ______ (e.g. ethanol) to dissolve substances if they are not water soluble.
- 'solvent' ✓
Worksheet
Presentation
Video
Lesson Details
Key learning points
- A solution is a type of mixture made of a solvent and a solute.
- Solutions form due to a solute dissolving in the solvent.
- Solubility is a measure of how well a chemical dissolves (soluble/insoluble).
- Many substances can act as a solvent; however, water is the most common.
- State symbols are used to identify the three states of matter and aqueous solutions in chemical equations.
Common misconception
Some think that because a solute can no longer be seen, or that a solvent becomes coloured when a solute dissolves, that the creation of a solution is a chemical change.
Create a salt solution, then evaporate the water (leaving salt crystals) to demonstrate that the salt and water have not chemically combined and therefore dissolving (to create a solution) is a physical change.
Keywords
Solute - A solute is a substance that has dissolved into a solvent.
Solvent - A solvent is a liquid into which a solute dissolves.
Soluble - When a substance dissolves in a solvent, it is described as soluble in that solvent.
Insoluble - A substance that does not dissolve in a particular solvent is described as insoluble.
State symbol - A state symbol is used in chemical equations to indicate the physical state of a substance.