Changing State

• What does changing state refer to?

  Transition of substances between solid, liquid, gas
• How does heating affect solids?

  It increases their particle energy and vibrations
• What happens to solids when heated?

  • Particles gain energy
  • Vibrations increase
  • Eventually change to liquid
• What is the melting point?

  Temperature where solids become liquids
• What occurs at the melting point?

  Particles can slide past each other, forming liquid
• What is the term for solids turning into liquids?

  Melting
• How does increased vibration affect solid particles?

  It weakens the forces holding them together
• What is the term for insufficient energy to overcome attraction between particles?

  Freezing
• What happens at the boiling point?

  Particles have enough energy to break bonds
• What is the term for liquids turning into gases?

  Boiling
• What is condensation?

  Process where gas turns into liquid
• What happens when a liquid cools?

  Particles lose energy and move less
• What is the effect of heating a liquid?

  Particles gain energy and move faster
• What is the boiling point?

  Temperature where liquids become gases
• What is the relationship between energy and particle movement?

  More energy means faster particle movement
• How do stronger forces between particles affect state changes?

  More energy is needed to change states
• What is the term for the process of a liquid becoming a gas?

  Evaporation
• What happens to particles during evaporation?

  Particles gain enough energy to escape
• What are the key points of state changes in substances?

  1. Heating increases particle energy
  2. Melting occurs at the melting point
  3. Boiling occurs at the boiling point
  4. Cooling decreases particle energy
  5. Freezing occurs when energy is insufficient
• What is the final state of a substance after boiling?

  Gas
• How does cooling affect the energy of particles?

  It decreases their energy and movement
• How does the amount of energy needed for state change depend on particle forces?

  Stronger forces require more energy to change
• What happens to particles when a substance is heated?

  They gain energy and vibrate more
• What is the significance of the boiling point in state changes?

  It indicates when a liquid becomes gas
• How do temperature and energy relate to state changes?

  Higher temperature means more energy for changes
• What is the final state of a substance after condensation?

  Liquid
• What is the effect of pressure on boiling point?

  Increased pressure raises the boiling point
• How does the energy of particles affect the state of a substance?

  More energy leads to gas state, less to solid
• What does the amount of energy needed for a substance to change state depend on?

  It depends on the strength of forces between particles.
• How does the strength of forces between particles affect energy requirements for state changes?

  The stronger the forces, the more energy is needed.
• What happens to a substance below its melting point?

  It remains solid.
• What happens to a substance above its boiling point?

  It becomes a gas.
• What state is a substance in between its melting and boiling points?

  It is a liquid.
• At what temperature does oxygen boil?

  -183 °C
• At what temperature does nitrogen boil?

  -196 °C
• At what temperature does bromine melt?

  -7 °C
• At what temperature does bromine boil?

  59 °C
• What state are oxygen and nitrogen at room temperature?

  They are gases.
• What state is bromine at room temperature?

  It is a liquid.
• How do the boiling points of oxygen and nitrogen compare to room temperature?

  Both are below room temperature.