1.1 Solids, Liquids and Gases
1. State the distinguishing properties of a solid in terms of its shape and volume.
A solid has a fixed shape and a fixed volume.
2. How does the shape and volume of a liquid differ from a solid?
A liquid has a fixed volume but no fixed shape; it takes the shape of the container it is in.
3. Describe the properties of a gas regarding shape and volume.
A gas has no fixed shape and no fixed volume.
4. Describe the separation of particles in a solid compared to a gas.
Particles in a solid are very close together (touching), whereas in a gas, they are far apart.
5. What is the arrangement of particles in a solid?
They are in a regular arrangement (or lattice).
6. Describe the arrangement of particles in a liquid.
They are in a random (or irregular) arrangement.
7. What is the specific motion of particles in a solid?
They vibrate about fixed positions.
8. Describe the motion of particles in a liquid.
They move around and slide over each other.
9. Describe the motion of particles in a gas.
They move quickly and randomly in all directions.
10. Define the change of state from solid to liquid and liquid to solid.
Solid to liquid is melting; liquid to solid is freezing.
11. Define the changes of state from liquid to gas.
This can occur through boiling or evaporating.
12. What is the name for the process of a gas turning into a liquid?
Condensing.
13. What is the effect of increasing temperature on the volume of a gas?
It causes the volume to increase.
14. What is the effect of increasing pressure on the volume of a gas?
It causes the volume to decrease.
15. Explain melting in terms of kinetic particle theory.
As a solid is heated, particles gain kinetic energy and vibrate faster until they have enough energy to overcome the attractive forces holding them in a regular arrangement.
16. Explain boiling in terms of kinetic particle theory.
As a liquid is heated, particles gain enough energy to completely overcome the forces of attraction between them, allowing them to move far apart as a gas.
17. On a heating curve, what is happening to the temperature during a change of state?
The temperature remains constant (shown as a horizontal line) because the energy is being used to break the forces between particles.
18. Explain, using kinetic particle theory, why increasing temperature increases gas volume.
Heating gives particles more kinetic energy, so they move faster and collide with the container walls more frequently and with more force, pushing them outward.
19. Explain, using kinetic particle theory, why increasing pressure reduces gas volume.
Increased pressure forces the particles closer together, reducing the amount of empty space between them.
1.2 Diffusion
20. What is diffusion?
The movement of particles in constant random motion from a region of higher concentration to a region of lower concentration.
21. Why does diffusion occur faster in gases than in liquids?
Gas particles have more kinetic energy and move much faster than liquid particles, with more space between them to move through.
22. How does relative molecular mass affect the rate of diffusion of a gas?
Gases with a lower relative molecular mass diffuse faster than gases with a higher relative molecular mass.
23. Explain why a "lighter" gas diffuses faster than a "heavier" gas.
At any given temperature, particles with lower mass move faster on average than heavier particles.