Particle model of matter

• What does the particle model of matter state?

  Everything is made up of lots of tiny particles.
• How does the particle model explain density?

  It relates the mass of a substance to how much space it takes up.
• What is the formula for density?

  Density = mass / volume
• What is the symbol for density?

  The symbol for density is the Greek letter ρ (rho).
• What happens to the density of a material when it is compressed?

  It becomes more dense as its particles move closer together.
• How can density be expressed in different units?

  Density can be given in kg/m³ or g/cm³.
• What does a dense material's particle arrangement look like?

  A dense material has its particles packed tightly together.
• What are the three states of matter?

  Solid, liquid, and gas.
• Why is the density of solids generally highest?

  Because the particles are closest together.
• How do the particles in liquids differ from those in solids?

  They can move past each other and form irregular arrangements.
• How do the particles in solids behave?

  They vibrate about fixed positions due to strong forces of attraction.
• What is the relationship between the density of liquids and solids?

  Liquids are generally less dense than solids.
• How do gas particles behave compared to liquid and solid particles?

  Gas particles have almost no forces of attraction and move freely at high speeds.
• What happens to the internal energy of a system when it is heated?

  The particles gain energy in their kinetic stores and move faster.
• What is the total internal energy of a system composed of?

  It is the total energy in the kinetic and potential energy stores of its particles.
• What occurs when a substance is heated enough to change state?

  The particles have enough energy to break the bonds holding them together.
• What is a physical change in the context of state changes?

  A change of state is a physical change, meaning the substance remains the same but in a different form.
• What happens to the mass of a substance during a change of state?

  The mass remains conserved; none of it is lost during the change of state.
• What is latent heat?

  Latent heat is the energy needed to change the state of a substance without changing its temperature.
• What happens to the temperature of a substance during melting or boiling?

  The temperature does not rise during melting or boiling, as energy is used to break bonds instead.
• How does energy transfer during condensing or freezing?

  Energy is released as bonds form between particles, but the temperature does not decrease until all particles have changed state.
• What is the relationship between temperature and the average energy in the kinetic stores of gas particles?

  The higher the temperature, the higher the average energy in the kinetic energy stores of the particles.
• What happens to gas particles when the temperature increases?

  The average speed of the gas particles increases as their kinetic energy increases.
• How do colliding gas particles create pressure?

  Gas particles exert a force on surfaces they collide with, creating pressure.
• What happens to the pressure in a sealed container as gas particles collide more frequently?

  The pressure increases due to more frequent collisions with the container walls.
• What are the key concepts related to density and states of matter?

  • Density measures the compactness of a substance.
  • Three states of matter: solid, liquid, gas.
  • Solid: particles closely packed, high density.
  • Liquid: particles close but can move, lower density than solids.
  • Gas: particles far apart, low density.
• What are the key points about internal energy and changes of state?

  • Internal energy is stored in kinetic and potential energy stores of particles.
  • Heating increases internal energy and can change temperature or state.
  • Changes of state conserve mass and are physical changes.
  • Latent heat is the energy needed for state changes without temperature change.
• How does particle motion in gases relate to temperature and pressure?

  • Gas particles move randomly at high speeds.
  • Temperature relates to average kinetic energy of particles.
  • Increased temperature raises particle speed and pressure due to more collisions.