States of matter

• What are the three states of matter?

  Solid, liquid, and gas
• What does the particle model explain?

  The particle model explains state changes in a substance based on particle arrangement, movement, and energy
• What are the characteristics of gas particles?


  • Arrangement: Random and far apart
  • Movement: Fast in all directions
  • Energy: High energy
• What are the characteristics of liquid particles?

  • Arrangement: Random and close together
  • Movement: move around each other
  • Energy: Moderate energy
• What are the characteristics of solid particles?

  • Arrangement: Regular and close together
  • Movement: Vibrate about fixed positions
  • Energy: Low energy
• What is the significance of the particle model in chemistry?

  • Explains state changes
  • Relates to arrangement, movement, and energy of particles
  • Fundamental concept in understanding matter
• What type of changes are state changes classified as?

  Physical changes
• Why can state changes be reversed?

  Because the chemical properties of the substance do not change
• What remains unchanged during a state change?

  The particles themselves do not change
• What aspects of particles change during a state change?

  Their arrangement, movement, and amount of stored energy
• What are the processes involved in state changes?

  • Melting
  • Freezing
  • Evaporation
  • Boiling
  • Condensing
  • Sublimation
  • Deposition
• What is the process called when a solid turns into a gas without becoming a liquid first?

  Sublimation
• What is the process called when a gas turns into a liquid?

  Condensing
• What is the process called when a liquid turns into a gas?

  Evaporation or boiling
• What is the process called when a liquid turns into a solid?

  Freezing
• What is the process called when a solid turns into a liquid?

  Melting
• What is the process called when a gas turns into a solid without becoming a liquid first?

  Deposition
• What type of forces attract particles to one another?

  Weak forces of attraction
• What happens to some attractive forces in a solid during melting?

  Some of these forces are overcome
• What must happen for evaporation and boiling to occur?

  Energy must be transferred from the surroundings to the particles
• Why do you heat ice to melt it?

  To transfer energy to the particles
• What happens to attractive forces during condensing?

  Some attractive forces form between particles
• What must occur for freezing to happen?

  Energy must be transferred from the particles to the surroundings
• Why does water vapor turn into droplets on a cold window?

  Because energy is transferred from the particles to the surroundings
• How can you predict the state of a substance?

  By knowing its temperature, melting point, and boiling point
• What are the states of a substance based on temperature ranges?

  • Below the melting point: solid
  • Between the melting point and boiling point: liquid
  • Above the boiling point: gas
• What happens to the temperature of a substance while it is boiling?

  The temperature stays constant while the liquid is boiling
• What occurs to particles during boiling?

  Particles escape from the liquid to form a gas
• What happens to the temperature of a substance while it is melting?

  The temperature stays constant while the solid is melting
• What is happening to the particles during melting?

  The added energy makes the particles break away from their fixed arrangement