C1.1 The particle model

• What is the particle model used to describe?

  The particle model is used to describe solids, liquids, and gases.
• Why is it important to draw diagrams when presenting particles?

  Diagrams help visualize the arrangement and behavior of particles.
• What happens to particles when a solid is sheared?

  The particles in a solid slide past each other when sheared.
• What are the differences between chemical and physical changes?

  • Chemical changes result in the formation of new substances.
  • Physical changes do not create new substances.
  • Examples of chemical changes include cooking and burning.
  • Examples of physical changes include melting and freezing.
• What happens to particles during chemical changes?

  Particles rearrange to form new substances during chemical changes.
• What is one example of a chemical change?

  Cooking an egg is an example of a chemical change.
• What are the forces between particles in a solid?

  The forces between particles in a solid are strong and hold them closely together.
• What is a limitation of the particle model?

  The particle model does not perfectly account for the space between atoms.
• How small are particles compared to everyday objects?

  Particles are much smaller than everyday objects, often at the atomic or molecular level.
• How does the distance between particles in a gas compare to that in a solid?

  The distance between particles in a gas is much greater than in a solid.
• If the diameter of a carbon atom is approximately $1.0 \times 10^{-10} \text{ m}$, what is the mean distance between carbon atoms in a gas?


  The mean distance between carbon atoms in a gas is approximately $5.7 \times 10^{-10} \text{ m}$.
• What is the diameter of a calcium atom?

  The diameter of a calcium atom is approximately $1.0 \times 10^{-10} \text{ m}$.
• Why does water expand when it freezes, unlike most other substances?

  Water expands when it freezes due to the unique arrangement of hydrogen bonds in ice.
• What is the significance of the particle model in understanding matter?

  The particle model helps explain the properties and behaviors of different states of matter.