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Year 10
AQA
Foundation

State changes: fundamentals

I can describe the processes of melting, freezing, boiling, and condensation, using a simple particle model to explain these state changes.

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New
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Year 10
AQA
Foundation

State changes: fundamentals

I can describe the processes of melting, freezing, boiling, and condensation, using a simple particle model to explain these state changes.

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Lesson details

Key learning points

  1. A simple particle model explains melting, boiling, freezing, and condensing processes.
  2. Boiling is when a liquid becomes a gas throughout, forming bubbles. Condensation is when gas turns into liquid.
  3. Melting is when a solid turns into a liquid with added energy. Freezing is the reverse: liquid to solid, losing energy.
  4. The particles remain the same size and shape as they do not have bulk properties like melting and boiling points.

Keywords

  • Melting - When a substance changes from a solid state to a liquid state.

  • Freezing - The process of a substance changing from a liquid state to a solid state.

  • Forces of attraction - A pulling force that keeps particles close together.

  • Boiling - When a substance in the liquid state is heated, gas bubbles form and it changes to the gas state.

  • Condensing - When a substance in the gas state is cooled and changes to a liquid state.

Common misconception

Pupils often think that the particles within the liquid will have melted or boiled rather than remain the same size and shape, i.e. atoms do not have bulk properties like melting and boiling points.

Ensure that you specifically say that the particles themselves will not melt or boil.

Using the word 'state' when referring to a state of matter, e.g. liquid state. This helps pupils understand that substances can exist in different states of matter. For example, oxygen can exist in the gas state, liquid state or solid state.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Lesson video

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Starter quiz

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6 Questions

Q1.
As particles gain energy, they are able to overcome the between them.
An image in a quiz
Correct Answer: forces of attraction
Q2.
For water, what is the temperature at which it turns from the liquid state to the gas state?
0°C
Correct answer: 100°C
50°C
–20°C
4°C
Q3.
Match the following key terms to their definitions.
Correct Answer:boiling,a substance in liquid state changes to gas state

a substance in liquid state changes to gas state

Correct Answer:boiling point,the temperature a substance changes from liquid state to gas state

the temperature a substance changes from liquid state to gas state

Correct Answer:condensing point,the temperature a substance changes from gas state to liquid state

the temperature a substance changes from gas state to liquid state

Correct Answer:freezing point,the temperature a substance changes from liquid state to solid state

the temperature a substance changes from liquid state to solid state

Correct Answer:melting,the substance in solid state changes into liquid state

the substance in solid state changes into liquid state

Correct Answer:melting point,the temperature a substance changes from solid state to liquid state

the temperature a substance changes from solid state to liquid state

Q4.
Which of the following statements describe what happens during condensing?
Correct answer: particles move closer together
particles start to align in a fixed arrangement
the particles become smaller
the temperature of the substance decreases
Correct answer: the volume of the substance decreases
Q5.
If a substance has a melting point of 50°C, at what temperature will it freeze?
-10°C
0°C
48°C
Correct answer: 50°C
100°C
Q6.
Models have limitations. What does this image of the particle model NOT attempt to show? Select all that apply.
An image in a quiz
arrangement of particles
Correct answer: movement of particles
Correct answer: forces between particles
Correct answer: elasticity of particles

Exit quiz

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6 Questions

Q1.
Which of the following statements describe what happens during freezing?
Correct answer: particles become fixed into position
particles become free to move over and around each other
particles end up in a random arrangement
Correct answer: particles end up in a regular arrangement
Correct answer: particles lose energy
Q2.
Imagine candles (wax melting point 65°C; boiling point 300°C) in a room at 25°C. The flames have just been extinguished (see image). What is the temperature of the melted parts?
An image in a quiz
somewhere around 25°C
somewhere between 25 and 65°C
exactly 65°C
Correct answer: somewhere between 65 and 300°C
somewhere above 300°C
Q3.
Which aspects of a particle change when a substance’s state of matter changes?
An image in a quiz
Correct answer: arrangement relative to other particles
Correct answer: energy of particle
Correct answer: movement of particle
shape of particle
size of particle
Q4.
What is inside the bubbles of boiling water?
air
nothing, only empty space
oxygen and hydrogen in the gas state
Correct answer: water in the gas state
Q5.
Commonly scientists only refer to melting and boiling points of substances. What is the state of matter of mercury at 25°C, if its freezing point is -39°C and condensing point is 357?
solid state
Correct answer: liquid state
gas state
none of the above
Q6.
Match the numbers in the image below with the correct state change.
An image in a quiz
Correct Answer:1,melting

melting

Correct Answer:2,boiling

boiling

Correct Answer:3,freezing

freezing

Correct Answer:4,condensing

condensing