P1 particle model of matter

• What are the three common states of matter?

  Solids, liquids, and gases
• How are particles arranged in solids, liquids, and gases?

  • Solids: Particles close together in a regular pattern
  • Liquids: Particles close together but not in a regular pattern
  • Gases: Particles far apart and not in any pattern
• How do particles behave in a solid?

  They vibrate but do not move from place
• How do particles behave in a liquid?

  They can move around each other
• How do particles behave in a gas?

  They move very rapidly
• What does density tell us about a material?

  Mass for a given volume
• What is the density of a brick compared to polystyrene?

  The brick has a high density
• How do you calculate density?

  Density = mass / volume
• What is the unit of density?

  Kilograms per meter cubed
• If a block of wood has a mass of 150 kg and a volume of $0.3 \text{ m}^3$, what is its density?


  $500 \text{ kg/m}^3$
• How does the particle model explain the density of solids, liquids, and gases?

  • Solids: High density due to closely packed particles
  • Liquids: High density due to close particles
  • Gases: Low density due to far apart particles
• Why do gases have a low density?

  Particles are very far apart
• What is an exception to the general density rules?

  Polystyrene has a low density
• Why does polystyrene have a low density despite being a solid?

  It has a very open structure with air spaces
• What can you observe under a microscope in polystyrene?

  Air spaces in its structure
• What does the density of a material tell us?

  The mass for a given volume
• What is the unit of density?

  Kilograms per cubic meter
• How are objects categorized when determining density?

  Into regular and irregular objects
• How do you measure the dimensions of a regular object?

  Using a ruler
• How do you calculate the volume of a cube?

  Length of side cubed
• How do you determine the density of an irregular object?

  Using the displacement method
• What is the first step in determining the density of an irregular object?

  Find the mass using a balance
• What is a Eureka can used for?

  To measure displaced water volume
• What happens when you place an object in water using a Eureka can?

  Water is displaced and flows out
• How do you measure the volume of water displaced?

  Using a measuring cylinder
• What does the volume of displaced water equal?

  The volume of the object
• What can you calculate once you have the mass and volume of an irregular object?

  Its density
• What are the steps to determine the density of a regular object?

  1. Measure the mass using a balance.
  2. Measure the length of the side with a ruler.
  3. Calculate the volume by cubing the length.
  4. Use the formula: Density = Mass / Volume.
• What are the steps to determine the density of an irregular object?

  1. Measure the mass using a balance.
  2. Fill a Eureka can with water.
  3. Place the object in the water to displace it.
  4. Measure the volume of displaced water.
  5. Use the formula: Density = Mass / Volume.
• What is meant by internal energy?

  Energy stored in a system by particles
• What happens when a material changes state?

  Internal energy changes during the process
• How do particles in a solid behave?

  They vibrate but do not move place to place
• How do particles in a liquid behave?

  They can move around each other
• How do particles in a gas behave?

  They move extremely rapidly
• What type of energy do all particles possess?

  Both kinetic and potential energy
• What are intermolecular forces?

  Forces between particles that give potential energy
• What is internal energy composed of?

  Total kinetic and potential energy of particles
• Why is internal energy important during changes of state?

  It determines the state of the material
• What is the process called when a solid turns into a liquid?

  Melting
• What happens to internal energy when a solid is heated?

  It increases