Coaching Centre
Chapter 4 review and test
A one-page summary of the nature of matter and a full chapter test: multiple choice, sorting and extended responses with marking guidelines.
One model, a lot of explaining. Before the chapter test, check you can use the particle model to explain each of these without looking back.
The whole chapter on one page
| What you see | What the particles are doing | Topic |
|---|---|---|
| Gases can be squashed; solids and liquids can't | Gas particles have lots of empty space between them | 4A |
| Liquids flow, solids keep their shape | Liquid particles slide past each other; solid particles are held in place and vibrate | 4B |
| Smells spread across a room | Gas particles move randomly and spread from high to low concentration (diffusion) | 4C |
| Lead is denser than aluminium; ice floats | Heavier particles or closer packing mean more mass per volume; ice has an open lattice | 4D |
| Tyres go hard on hot days | Faster particles hit the walls more often and harder | 4E |
| Bridges grow in summer | Particles vibrate more and move further apart (they don't get bigger) | 4F |
| Boiling water stays at 100 °C | Energy is used to separate the particles, not speed them up (latent heat) | 4G |
Words you must be able to use
matter · particle · atom · molecule · solid · liquid · gas · plasma · compressibility · viscosity · particle model · forces of attraction · kinetic energy · diffusion · density · physical property · displacement · tensile strength · compressional strength · hardness · brittle · pressure · melting point · boiling point · expansion · contraction · conduction · conductor · insulator · heat capacity · melting · freezing · evaporation · boiling · condensation · sublimation · deposition · latent heat · heating curve
Chapter 4 test
Which property is shared by liquids and gases but not solids?
Both liquids and gases flow; only gases compress easily.
Which diagram shows particles in a gas?
Gas particles are far apart and randomly arranged.
John Dalton's contribution to the particle model was important because he
Evidence is what made it science.
Diffusion does not really happen in solids because solid particles
They vibrate but can't move to new positions.
A 40 cm³ block has a mass of 32 g. Its density is
32 ÷ 40 = 0.8 g/cm³, so it floats on water.
Oil and vinegar are shaken and left to settle. The oil ends up on top because it
Less dense substances rise above denser ones.
Pumping more air into a ball increases its pressure because
More particles, more collisions per second.
A substance has a melting point of −39 °C and a boiling point of 357 °C. At room temperature (25 °C) it is a
25 °C is between −39 °C and 357 °C. (This is mercury.)
Railway lines buckle in a heatwave when there is no room for them to
Heated steel expands; blocked expansion creates huge forces.
Saucepan handles are usually plastic or wood because these materials are
Insulators slow the flow of heat to your hand.
While water is boiling, the heat being added is used to
That is latent heat.
Dew forms on grass overnight because
Cold surfaces cause vapour to condense.
Sort each term.
A student fills a balloon with air and ties it off. She places it in a freezer for an hour, then leaves it in the sun for an hour. Predict what happens to the balloon each time and explain your predictions using the particle model.
In the freezer the balloon will shrink. The air particles lose kinetic energy and move more slowly, so they hit the inside of the balloon less often and with less force. The pressure inside drops and the rubber pulls the balloon smaller. In the sun the balloon will grow. The particles gain kinetic energy and move faster, hitting the balloon more often and harder, so the pressure rises and the balloon expands. The number of particles inside never changes, only how fast they move.
A student adds 10 mL of salt to 100 mL of water and stirs until it dissolves. She expects 110 mL of salty water but measures only 103 mL. Explain this result using the particle model, and suggest one way she could improve the accuracy of her measurements.
Water particles are close together but there are small spaces between them. When the salt dissolves, the salt particles spread out and fit into some of those spaces, so the salty water takes up less volume than the water and salt did separately. No particles are lost, so the mass is still the total of the water and salt. Also, 10 mL of salt crystals includes air gaps between the grains, which disappear when the salt dissolves. To improve accuracy she could measure the salt by mass on a balance instead of by volume, read the measuring cylinder at eye level from the bottom of the meniscus, and repeat the experiment three times to find an average.