Particle Model

• What is the particle model used for in physics?

  To explain the world around us
• What does density measure?

  How much stuff there is in a given volume
• If two objects have the same volume but different masses, what can be inferred about their densities?

  The object with the greater mass has a higher density
• What symbol is used to represent density?

  Rho (ρ)
• How is density calculated?

  Density is equal to mass divided by volume
• What are the standard units for density?

  Kilograms per cubic meter (kg/m³)
• What happens to the density measurement if mass is measured in grams and volume in cubic centimeters?

  The density can be expressed in grams per cubic centimeter (g/cm³)
• What are the characteristics of particles in solids, liquids, and gases?

  • Solids: Close-packed, regular arrangement, limited movement
  • Liquids: Densely packed, random motion, can move past each other
  • Gases: Spread out, rapid random motion, can be compressed
• What occurs when a solid is heated?

  It melts into a liquid
• What is evaporation?

  When a liquid turns into a gas below its boiling temperature
• What is sublimation?

  When a solid turns directly into a gas
• What is internal energy defined as?

  The total kinetic and potential energies of all particles in a system
• How does internal energy relate to temperature?

  As internal energy increases, temperature also increases until a change of state occurs
• What is specific heat capacity?

  The amount of energy required to raise the temperature of 1 kg of a substance by 1 degree Celsius
• What is the equation relating change in internal energy to mass, specific heat capacity, and temperature change?

  $\Delta E =$$M C \Delta \Theta$
• What is specific latent heat?

  The amount of energy required to change the state of 1 kg of a substance with no change in temperature
• What is the equation for calculating energy during a change of state?

  $E =$$M L$
• How does increasing temperature affect gas molecules in a container?

  It increases their kinetic energy and speed
• What happens to gas pressure when the volume of the container increases at constant temperature?

  The pressure decreases
• What is the relationship between pressure and volume of a gas at constant temperature?

  Pressure is inversely proportional to volume
• What is the equation that relates pressure and volume of a gas?

  $P_1 V_1 =$$P_2 V_2$
• What happens to internal energy when work is done on a gas?

  It increases the internal energy of the gas
• What is the summary of the particle model?

  • Explains the behavior of solids, liquids, and gases
  • Describes changes of state (melting, boiling, evaporation, condensation, freezing, sublimation)
  • Relates internal energy to temperature and state changes
  • Involves specific heat capacity and specific latent heat