Question

a.) identify the names of the described phase changes. you must correctly identify all 6 for it to be counted as correct.
gas to liquid
solid to liquid
liquid to solid
liquid to gas
solid to gas
gas to solid
b.) which of the following phase changes require heat to enter the object in order to occur? choose all that apply.
deposition
melting
boiling
sublimation
condensation
freezing

Explanation:

Part a)

• Gas to liquid: The phase change from gas to liquid is called condensation. In this process, gas molecules lose energy and come together to form a liquid.
• Solid to liquid: When a solid turns into a liquid, it is known as melting. Heat is usually added to break the intermolecular forces holding the solid structure together.
• Liquid to solid: The phase change from liquid to solid is freezing. Here, liquid molecules lose energy and arrange themselves into a more ordered solid structure.
• Liquid to gas: When a liquid becomes a gas, it is called vaporization (or boiling when it occurs at a specific temperature throughout the liquid). Liquid molecules gain enough energy to escape into the gaseous state.
• Solid to gas: The direct phase change from solid to gas is sublimation. Substances like dry ice (solid carbon dioxide) undergo sublimation, changing directly from solid to gas without passing through the liquid phase.
• Gas to solid: The direct phase change from gas to solid is deposition. For example, frost forms when water vapor in the air deposits directly onto a cold surface as ice.

• Deposition: Deposition is the change from gas to solid. It is an exothermic process, meaning heat is released (not absorbed), so it does not require heat to enter the object.
• Melting: Melting is the change from solid to liquid. Heat must be added (enter the object) to break the intermolecular forces in the solid, so it requires heat input.
• Boiling: Boiling is the change from liquid to gas (a type of vaporization). Heat must be added to the liquid to provide the energy needed for molecules to escape into the gas phase, so it requires heat input.
• Sublimation: Sublimation is the change from solid to gas. Heat must be added to the solid to provide enough energy for the molecules to go directly from the solid to the gas phase, so it requires heat input.
• Condensation: Condensation is the change from gas to liquid. It is an exothermic process (heat is released), so it does not require heat to enter the object.
• Freezing: Freezing is the change from liquid to solid. It is an exothermic process (heat is released), so it does not require heat to enter the object.

Answer:

• Gas to liquid: Condensation
• Solid to liquid: Melting
• Liquid to solid: Freezing
• Liquid to gas: Vaporization (or Boiling)
• Solid to gas: Sublimation
• Gas to solid: Deposition

Part b)