Changes of State and Particle Model

• What is the definition of density?

  The mass per unit volume of a material
• What is the equation for density?

  ⍴ = m/v
• What are the units for density?

  kg/m³
• What is the least dense state of matter?

  Gas
• What is the order of states of matter from least to most dense?

  Gas, Liquid, Solid
• How are particles arranged in a solid?

  Tightly packed in a regular arrangement
• What can particles in a solid do?

  Vibrate on the spot
• How are particles arranged in a liquid?

  Close together, but irregularly arranged
• What can particles in a liquid do?

  Flow over each other
• How are particles arranged in a gas?

  Separated with no regular arrangement
• What can particles in a gas do?

  Move freely
• What is always conserved during a change of state?

  Mass
• How does a change of state differ from a chemical change?

  Material can return to previous properties
• What is sublimation?

  Solid changes into gas without liquid
• What is evaporation?

  Liquid changes into gas state
• What is the opposite of evaporation?

  Condensation
• What happens when water boils in an open pan?

  Some water evaporates, decreasing mass
• Why does the mass of the pan decrease when water boils?

  Water evaporates and turns into vapour
• What processes occur when a bathroom mirror mists up?

  Water vapour condenses on the cooler mirror
• What are the steps involved when a bathroom mirror mists up?

  • Hot water evaporates to form vapour
  • Vapour lands on the cooler mirror
  • Vapour condenses to liquid on the mirror