1.5.2 Changes of State: Melting, Boiling, and Sublimation

• What are the three common states of matter?

  Solid, liquid, gas
• What is the process called when a solid changes into a liquid?

  Melting
• What happens to the particles in a solid during melting?

  Gain energy to break free
• What is the boiling point of water in degrees Celsius?

  100°C
• What is an example of a gas?

  Air
• What happens to the temperature of steam when heated further?

  Increases
• What happens to the temperature during the boiling process at 100°C?

  Stays constant
• What is the definition of sublimation?

  Solid to gas transformation
• What is melting?

  Solid to liquid
• What is produced when water boils?

  Steam
• Sublimation involves a liquid phase.

  False
• Sublimation involves the solid transforming into a liquid before becoming a gas.

  False
• What type of intermolecular forces must be overcome during sublimation?

  Intermolecular forces
• What are the starting and ending phases of sublimation?

  Solid to gas
• Arrange the phase changes in order of increasing temperature:

  1️⃣ Heating to 100°C

  2️⃣ Boiling at 100°C

  3️⃣ Steam heating
• What is the boiling point of a substance?

  • The temperature at which a liquid substance transitions to a gas state
• What is the critical point on the phase diagram?

  • The critical point is the point where the liquid and gas phases become indistinguishable.
• If you wanted to observe the surface of a cell in great detail, which type of microscope would you use?

  Scanning electron microscope
• What is the name of the region between the liquid and gas phases on the phase diagram?

  Vapor
• Why do the melting and boiling points appear as lines and not single temperatures on the phase diagram?

  The amount of pressure changes the boiling and melting points of substances
• What are the three phase changes discussed in the study material?

  Melting, boiling, sublimation
• What change of state occurs when a liquid becomes a gas?

  Boiling
• What type of energy must a solid absorb for sublimation to occur?

  Heat
• What change of state occurs when a solid becomes a liquid?

  Melting
• Why are the melting and boiling points shown as lines and not single temperatures?

  • The melting and boiling points are lines because the amount of pressure changes the boiling and melting points of substances.
• What is the name of the region between the solid and liquid phases on the phase diagram?

  Triple Point
• What is an example of a substance that undergoes sublimation?

  Dry ice
• What is the melting point of a substance?

  • The temperature at which a solid substance transitions to a liquid state
• What happens to energy during boiling?

  It is absorbed
• Ice melting into water is an example of boiling.

  False
• Match the phase change with its initial and final states:

  Melting ↔️ Solid to Liquid

  Boiling ↔️ Liquid to Gas

  Sublimation ↔️ Solid to Gas
• What does the image show the effect of on phase change temperatures?

  Pressure
• Match the change of state with its example:

  Melting ↔️ Ice melting into water

  Boiling ↔️ Water boiling into steam

  Sublimation ↔️ Dry ice evaporating into CO2
• Match the phase change with its application and benefit:

  Melting ↔️ Cooking with butter: Softens for mixing

  Boiling ↔️ Cooking pasta: Cooks evenly and quickly

  Sublimation ↔️ Freeze-drying coffee: Preserves flavor
• Why is boiling water used to cook pasta?

  Cooks pasta evenly