particle model of matter

• What is the formula for density?

  $\rho =$$\frac{m}{V}$
• What units are used for density?

  Kilograms per metre cubed (kg/m³)
• How does density depend on atomic spacing?

  Density depends on the spacing of atoms in matter
• How do the densities of solids and liquids compare?

  Solids and liquids have similar densities
• What is the main exception to the density comparison between solids and liquids?

  Ice has a lower density than water
• How does the density of gases compare to solids and liquids?

  Gases have a far lower density
• What happens to the spacing between atoms in gases?

  The spacing increases by a factor of ten
• What remains constant during a change of state?

  The mass of the substance
• What happens to the weight of gas produced from evaporating 20g of liquid?

  The gas will also weigh 20g
• Why are changes of state considered physical changes?

  They retain original properties when reversed
• What are the changes of state between solid, liquid, and gas?

  • Melting: Solid to Liquid
  • Freezing: Liquid to Solid
  • Evaporating: Liquid to Gas
  • Condensing: Gas to Liquid
  • Sublimation: Solid to Gas
• What is internal energy?

  Energy stored by particles within a system
• What forms can internal energy take?

  Kinetic and potential energy
• What effect does heating have on particle energy?

  It increases the energy of the particles
• What is specific heat capacity?

  Energy required to raise 1kg by 1°C
• What is the formula for change in thermal energy?

  $\Delta E =$$m \times c \times \Delta T$
• What is specific latent heat?

  Energy needed to change state without temperature change
• What is the specific latent heat of fusion?

  Energy to melt or freeze a substance
• What is the specific latent heat of vaporisation?

  Energy to boil or condense a substance
• What happens to energy during melting and evaporating?

  Energy is absorbed during these processes
• What happens to energy during freezing and condensing?

  Energy is released during these processes
• What is sublimation?

  Solid goes straight to gas
• What occurs at point A on the temperature graph of ice?

  It is in solid state
• What happens from point B to C on the temperature graph?

  No temperature change due to melting
• What occurs from point D to E on the temperature graph?

  Water is boiling, takes longer
• How is gas pressure related to molecular motion?

  Pressure is due to molecules colliding with walls
• How does temperature affect gas pressure?

  Higher temperature increases average kinetic energy
• What is Boyle's law?

  Increasing volume decreases pressure at constant temperature
• What is the formula for Boyle's law?

  $P_1V_1 =$$m$
• What happens when work is done on a gas?

  It increases the gas's temperature
• How does adding more particles to a fixed volume affect pressure?

  It increases the pressure due to more collisions
• What happens to particles in a smaller volume?

  Particles collide more frequently with walls
• How does the velocity of particles change in a smaller volume?

  Particles gain momentum and velocity increases
• Boyle's Law


  A scientific principle that describes the relationship between pressure and volume of a gas at constant temperature.