Predict State Changes - Middle School Physical Science

What happens to particle spacing when a substance changes from gas to liquid?

Particles move closer together. Gas particles condense as attractions pull them together.
Which direction of thermal energy transfer is required for melting: gain or loss?

Gain of thermal energy. Energy input breaks solid bonds to form liquid.
Identify the state change when a solid is heated until it becomes a liquid.

Melting. Heating adds thermal energy to break solid bonds.
What is the name of the phase change from liquid to solid when thermal energy is removed?

Freezing. Cooling allows particles to lock into fixed positions.
What phase change occurs when a liquid gains thermal energy and becomes a gas?

Vaporization. Heat gives particles enough energy to escape liquid's surface.
Identify the state change when thermal energy is removed from water vapor and it becomes liquid water.

Condensation. Water vapor loses energy and particles bond to form liquid droplets.
Which state change occurs when a substance releases thermal energy: boiling, condensation, or sublimation?

Condensation. Only condensation releases energy; boiling and sublimation absorb it.
Which direction of thermal energy transfer is required for freezing: gain or loss?

Loss of thermal energy. Forming solid bonds releases energy to surroundings.
Which option best describes evaporation: phase change at the surface or throughout the liquid?

At the surface of the liquid. Only surface particles have enough energy to escape.
Which state change occurs when water absorbs thermal energy but stays at $100\,^{\circ}\text{C}$ at standard pressure?

Boiling (liquid to gas). Energy converts liquid to gas; temperature constant during change.
Identify the state change when a gas loses thermal energy and becomes a liquid.

Condensation. Gas loses energy and forms liquid bonds.
Which direction of thermal energy transfer causes melting, vaporization, or sublimation: gain or loss?

Gain of thermal energy. Energy input breaks bonds for solid→liquid→gas transitions.
What is the name of the phase change from liquid to gas throughout the liquid at its boiling point?

Boiling. Occurs when liquid reaches temperature where vapor pressure equals atmospheric pressure.
Which phase change is occurring if a substance is heating and its particles overcome attractions to escape?

Vaporization. Heating until particles escape liquid surface is vaporization.
What is the phase change called when a gas becomes a solid without becoming a liquid first?

Deposition. Direct gas-to-solid transition occurs when particles lose energy rapidly.
What happens to the state of matter when thermal energy is removed from a liquid at its freezing point?

It freezes: liquid changes to solid. Removed energy allows particles to form rigid bonds.
Identify the state change: water droplets form on the outside of a cold glass in warm air.

Condensation (gas liquid). Water vapor cools on cold surface and forms liquid.
Which process releases thermal energy: boiling, sublimation, or freezing?

Freezing releases thermal energy. Particles form bonds and release stored energy.
Which option describes particle spacing when a substance changes from liquid to gas?

Particles spread farther apart. Gas particles have more energy and space than liquid particles.
What state change occurs when a solid gains thermal energy until it becomes a liquid?

Melting (solid liquid). Adding thermal energy breaks bonds between particles in the solid structure.
What is the name of the phase change from gas to liquid when thermal energy is removed?

Condensation. Cooling slows gas particles enough to form liquid bonds.
Identify the state change: dry ice changes directly into carbon dioxide gas.

Sublimation (solid to gas). Solid CO₂ gains energy to become gas without melting.
Which direction does thermal energy flow between objects at different temperatures?

From higher temperature to lower temperature. Heat always flows from hot to cold to reach thermal equilibrium.
What happens to particle kinetic energy (average speed) when thermal energy is removed from a substance?

It decreases. Less thermal energy means slower particle movement.
Identify the state change: a substance releases thermal energy and changes from gas to solid.

Deposition. Releasing energy to go directly from gas to solid is deposition.
During melting or boiling, added thermal energy is mainly used to change what: temperature or particle spacing?

Particle spacing (potential energy). Energy overcomes intermolecular forces rather than increasing temperature.
Which state change occurs when water at $0\,^{\circ}\mathrm{C}$ has thermal energy removed?

Freezing (liquid water becomes solid ice). $0\,^{\circ}\mathrm{C}$ is water's freezing point.
What is the name of the state change from solid to liquid when thermal energy is added?

Melting. Adding thermal energy breaks bonds between solid particles.
Identify the state change: frost forms on a window when the air is cold and humid.

Deposition (gas to solid). Water vapor loses energy and forms ice crystals directly.
Which state change is endothermic: melting, freezing, or condensation?

Melting. Endothermic means absorbing energy; melting requires energy input.
What happens to a solid when thermal energy is added until it reaches its melting point?

It melts: solid changes to liquid. Added energy breaks bonds between particles in fixed positions.
Which state change occurs when a substance absorbs thermal energy: melting, freezing, or condensation?

Melting. Only melting absorbs thermal energy; freezing and condensation release it.
Which option best describes particle spacing when a substance changes from liquid to gas?

Particles spread farther apart. Gas particles have more energy and need more space to move.
Which direction of thermal energy transfer causes freezing, condensation, or deposition: gain or loss?

Loss of thermal energy. Energy removal allows bonds to form for gas→liquid→solid.
What change of state occurs when a liquid loses thermal energy and becomes a solid?

Freezing. Particles lose energy and lock into fixed positions.
Identify the state change when a liquid is cooled until it becomes a solid.

Freezing. Cooling removes thermal energy from liquid particles.
What state change occurs when a liquid gains thermal energy until it becomes a gas?

Vaporization (evaporation/boiling). Added energy overcomes intermolecular forces, allowing particles to escape.
What phase change occurs when a solid gains thermal energy and becomes a liquid?

Melting. Heat breaks bonds between particles, allowing them to flow as liquid.
Identify the state change when frost forms from water vapor on a cold window.

Deposition. Water vapor forms solid ice crystals directly on cold surfaces.
Which state change is occurring if dry ice changes directly into carbon dioxide gas?

Sublimation (solid to gas). Solid CO₂ gains energy to become gas without melting.
Which direction of thermal energy transfer is required for deposition: gain or loss?

Loss of thermal energy. Forming solid bonds from gas releases energy.
What is the name of the state change from liquid to gas when thermal energy is added?

Vaporization. Heat gives particles enough energy to escape liquid bonds.
What is the name of the phase change from solid directly to gas when thermal energy is added?

Sublimation. Particles gain enough energy to skip liquid phase entirely.
What state change occurs when a liquid loses thermal energy and becomes a solid?

Freezing. Liquid particles lose energy and lock into solid structure.
Which state change occurs when a substance releases thermal energy but stays at the same temperature at $0\,^{\circ}\text{C}$ (water)?

Freezing (liquid to solid). Energy released as liquid forms solid bonds at melting point.
Identify the state change for water when thermal energy is removed and it goes from gas to liquid.

Condensation. Water vapor loses energy to form liquid droplets.
Identify the state change: a substance absorbs thermal energy and changes from solid to gas.

Sublimation. Absorbing energy to go directly from solid to gas is sublimation.
Which state change occurs when a substance absorbs thermal energy but stays at the same temperature at $0\,^{\circ}\text{C}$ (water)?

Melting (solid to liquid). Energy breaks solid bonds; temperature constant during phase change.
What happens to temperature during boiling if thermal energy continues to be added at the boiling point?

Temperature stays constant until boiling finishes. Energy converts liquid to gas, not raising temperature.
What change of state is sublimation?

Solid to gas without becoming a liquid. Direct transition skips the liquid phase entirely.
Which state of matter has particles with the greatest average kinetic energy at the same substance and pressure?

Gas. Gas particles move fastest with weakest attractions.
What is the name for the energy absorbed or released during a phase change with no temperature change?

Latent heat. Energy used to change phase without changing temperature.
Which direction of thermal energy transfer is required for sublimation: gain or loss?

Gain of thermal energy. Breaking solid bonds directly to gas requires energy.
Which state change is occurring when dry ice turns directly from solid to gas as thermal energy is added?

Sublimation. Solid CO₂ absorbs energy to become gas without melting.
What change of state occurs when a liquid gains enough thermal energy to become a gas?

Vaporization (evaporation/boiling): liquid to gas. Energy overcomes intermolecular forces holding liquid together.
Identify the state change: frost forms when water vapor turns directly into ice on a window.

Deposition. Gas loses thermal energy to become solid directly.
What happens to the state of matter when thermal energy is added to a solid at its melting point?

It melts: solid changes to liquid. Added energy breaks bonds between particles in fixed positions.
Identify the state change when thermal energy is added to ice and it becomes liquid water.

Melting. Ice absorbs energy, breaking bonds to form freely moving water molecules.
What happens to particle potential energy during melting as thermal energy is added?

It increases. Energy breaks attractions between particles.
What is the name of the phase change from liquid to gas at the surface when thermal energy is added?

Evaporation. Surface particles gain enough energy to escape into gas phase.
Which state of matter has particles packed closely and vibrating in place?

Solid. Lowest energy state with strongest intermolecular forces.
Which has more thermal energy at the same temperature: water vapor or liquid water?

Water vapor (gas). Gas particles have highest kinetic energy of all phases.
Which direction of thermal energy change causes melting, vaporization, and sublimation?

Adding thermal energy (heating). These transitions require energy input to break bonds.
What happens to temperature during a phase change while thermal energy is still added or removed?

Temperature stays constant. Energy goes into breaking/forming bonds, not increasing kinetic energy.
Identify the change in particle arrangement when a substance freezes.

Particles become more ordered and tightly packed. Loss of thermal energy creates organized crystalline structure.
What is the name of the state change from gas to liquid when thermal energy is removed?

Condensation. Cooling slows gas particles until they form liquid bonds.
What happens to temperature during a phase change while thermal energy is added or removed?

Temperature stays constant at the phase-change point. Energy goes into breaking/forming bonds, not raising temperature.
What happens to temperature during a phase change at constant pressure while thermal energy is added?

Temperature stays constant. Energy goes into breaking bonds, not raising temperature.
What is the name of the state change from liquid to gas at the surface when thermal energy is added?

Evaporation. Surface molecules gain enough energy to escape as gas.
Identify the state change: liquid water loses thermal energy and becomes ice.

Freezing. Liquid loses thermal energy to become solid.
What is the name of the state change from solid directly to gas when thermal energy is added?

Sublimation. Solid particles gain enough energy to skip the liquid phase.
Identify the state change when water vapor cools and forms liquid droplets on a cold surface.

Condensation: gas to liquid. Cold surface removes energy from water vapor.
During a phase change at the melting or boiling point, what happens to temperature as heat is added?

Temperature stays constant. Energy breaks bonds instead of raising temperature during phase change.
What is the name of the energy used to change state without changing temperature?

Latent heat. Energy absorbed or released during phase transitions.
Which state of matter generally has the lowest particle kinetic energy: solid, liquid, or gas?

Solid. Particles vibrate in fixed positions with minimal kinetic energy.
What is the name of the phase change from solid directly to gas when thermal energy is added?

Sublimation. Heat breaks solid bonds directly into gas without liquid phase.
Which direction of thermal energy change causes freezing, condensation, or deposition?

Thermal energy decreases (heat released). Energy loss allows particles to form stronger bonds.
What happens to the state of matter when thermal energy is added to a liquid at its boiling point?

It boils (vaporizes): liquid changes to gas. Added energy gives particles enough kinetic energy to escape liquid.
What change of state occurs when a liquid gains thermal energy and becomes a gas?

Vaporization (evaporation/boiling). Added energy allows particles to overcome intermolecular forces.
What happens to temperature during a phase change if thermal energy is still being added or removed?

Temperature stays constant. Energy goes into breaking/forming bonds, not increasing kinetic energy.
What change of state occurs when a solid gains thermal energy and becomes a liquid?

Melting. Thermal energy breaks bonds between particles in fixed positions.
Which state has the strongest particle attractions: solid, liquid, or gas (for the same substance)?

Solid. Solid particles are held tightly by strong intermolecular forces.
What change of state occurs when a solid gains thermal energy and becomes a liquid?

Melting. Thermal energy breaks bonds between particles in the solid structure.
What is the name of the phase change from solid directly to gas when thermal energy is added?

Sublimation. Particles gain enough energy to escape solid directly to gas phase.
What change of state occurs when a gas loses thermal energy and becomes a liquid?

Condensation. Gas particles slow down and attract into liquid form.
What phase change occurs when a gas loses thermal energy and becomes a solid directly?

Deposition. Gas particles lose energy and form solid without liquid phase.
Which state change occurs when thermal energy is added and particles spread farther apart: condensation or vaporization?

Vaporization. Energy input overcomes attractive forces between liquid particles.
Which state change occurs when ice at $0\,^{\circ}\mathrm{C}$ has thermal energy added?

Melting (solid ice becomes liquid water). $0\,^{\circ}\mathrm{C}$ is ice's melting point.
Identify the state change when liquid water at $100\,^{\circ}\mathrm{C}$ gains thermal energy at constant pressure.

Boiling (vaporization): liquid to gas. $100\,^{\circ}\mathrm{C}$ is water's boiling point at 1 atm.
Identify the state change: a substance releases thermal energy and changes from liquid to solid.

Freezing. Releasing energy to go from liquid to solid is freezing.
Choose the correct prediction: adding thermal energy to a solid causes freezing, melting, or deposition?

Melting. Adding energy to solid causes it to become liquid.
Identify what happens to temperature during boiling at the boiling point while heating continues.

Temperature stays constant. Energy converts liquid to gas, not raising temperature.
What is the name of the phase change from liquid to gas that occurs when thermal energy is added?

Vaporization (evaporation/boiling). Heat gives particles enough energy to escape liquid bonds.
Which direction of thermal energy change causes melting, vaporization, or sublimation: added or removed?

Added thermal energy. These transitions require energy input to overcome intermolecular forces.
What change of state occurs when a gas loses thermal energy and becomes a solid directly?

Deposition. Gas particles lose energy and form solid bonds without becoming liquid.
What is the name of the phase change from gas directly to solid when thermal energy is removed?

Deposition. Gas particles lose energy and form solid bonds directly.
What phase change occurs when a solid gains thermal energy and becomes a gas directly?

Sublimation. Heat gives solid particles enough energy to escape directly as gas.
Identify the state change when thermal energy is added to liquid water and it becomes water vapor.

Vaporization. Water absorbs energy until molecules escape as gas.
Which direction of thermal energy change causes freezing, condensation, or deposition: added or removed?

Removed. Energy loss forms bonds for gas→liquid→solid transitions.
Which state change occurs when water vapor releases thermal energy and becomes liquid at $100\,^{\circ}\text{C}$ ?

Condensation (gas to liquid). Gas releases energy to form liquid bonds at boiling point.
Which process releases thermal energy to the surroundings: freezing or melting?

Freezing releases thermal energy. Bond formation releases energy to surroundings.
Which state of matter has a definite shape and definite volume?

Solid. Particles are tightly packed in fixed positions.
What change of state occurs when a solid absorbs thermal energy and becomes a liquid?

Melting. Thermal energy breaks bonds between particles in fixed positions.
Identify the state change when a liquid loses thermal energy and becomes a solid.

Freezing. Liquid loses energy and forms rigid structure.
What change of state is deposition?

Gas to solid without becoming a liquid. Direct transition skips the liquid phase entirely.
What change of state occurs when a solid gains thermal energy and becomes a gas without melting?

Sublimation (solid gas). Heat breaks solid bonds directly into gas, skipping liquid phase.
Which phase change occurs when dry ice changes directly into carbon dioxide gas?

Sublimation. Solid CO₂ transitions directly to gas at normal pressure.
What is the name of the phase change from gas directly to solid when thermal energy is removed?

Deposition. Gas particles lose energy and form solid bonds directly.
Which state of matter has particles that slide past each other and take the shape of the container?

Liquid. Moderate energy allows flow but maintains cohesion.
Which term names the energy absorbed to change state without changing temperature?

Latent heat (energy for a phase change). Hidden heat that changes state, not temperature.
Identify the state change: a puddle disappears slowly at room temperature without boiling.

Evaporation (liquid gas). Surface molecules gain energy from air and escape.
Which state change is predicted when thermal energy is removed from liquid water at $0\,^{\circ}\text{C}$ ?

Freezing. At melting point, removed energy causes liquid to solidify.
What happens to temperature during melting if thermal energy continues to be added at the melting point?

Temperature stays constant until melting is complete. Energy goes into breaking bonds, not raising temperature.
Identify the state change: Water vapor forms droplets on a cold mirror.

Condensation (gas liquid). Cold surface removes energy from water vapor, forming liquid.
Which state change is predicted when thermal energy is added to a solid until it becomes a liquid?

Melting. Adding thermal energy causes solid to become liquid.
What is the phase change called when a liquid becomes a solid because thermal energy is removed?

Freezing. Removing thermal energy causes liquid particles to lock into fixed positions.
What change of state occurs when a liquid releases thermal energy and becomes a solid?

Freezing (solidification). Particles lose energy and lock into fixed positions.
Identify the phase change: frost forms on a window when water vapor turns to ice.

Deposition. Water vapor freezes directly to ice crystals on cold glass.
Identify the state change when a solid gains thermal energy and becomes a liquid.

Melting. Solid gains energy and breaks rigid bonds.
What happens to temperature during a phase change at constant pressure while thermal energy is removed?

Temperature stays constant. Energy from forming bonds doesn't change temperature.
Which state change is exothermic: evaporation, sublimation, or deposition?

Deposition. Exothermic means releasing energy; gas to solid releases energy.
Identify the state change when frost forms as water vapor turns directly into ice on a cold surface.

Deposition. Gas particles lose energy and bond directly as solid.
Which state of matter has particles packed most closely with the strongest attractions?

Solid. Particles vibrate in place with minimal movement.
What is the name of the phase change from gas to liquid when thermal energy is removed?

Condensation. Gas particles lose energy and form liquid bonds.
Identify the state change: dry ice turns directly into carbon dioxide gas at room conditions.

Sublimation (solid gas). CO₂ solid bonds break directly to gas at normal pressure.
Which direction of thermal energy change causes melting, vaporization, or sublimation: added or removed?

Added. Energy input breaks bonds for solid→liquid→gas transitions.
What happens to particle average kinetic energy during a phase change at constant temperature?

It stays constant. Energy goes into breaking/forming bonds, not particle motion.
Which direction of thermal energy change causes melting, vaporization, or sublimation: absorbed or released?

Absorbed. These transitions require energy input to break bonds.
Which has more thermal energy at the same temperature: liquid water or ice?

Liquid water. Liquid particles have more kinetic energy than solid.
Which state change is predicted when thermal energy is removed from a gas until it becomes a liquid?

Condensation. Removing thermal energy causes gas to become liquid.
Which has higher average particle kinetic energy at the same substance: liquid or gas?

Gas. Gas particles move fastest and have the highest kinetic energy.
Which change in particle motion occurs when thermal energy is added: faster or slower average motion?

Faster average particle motion. Higher thermal energy means higher kinetic energy.
What is the name of the state change from solid directly to gas when thermal energy is added?

Sublimation. Heat makes solid particles escape directly to gas phase.
What change of state occurs when a gas loses thermal energy and becomes a liquid?

Condensation (gas liquid). Cooling slows gas particles until attractions pull them together.
What is the name of the state change from gas directly to solid when thermal energy is removed?

Deposition. Gas particles lose energy and form solid bonds directly.
Identify the state change: a puddle disappears slowly at room temperature without boiling.

Evaporation (liquid to gas). Surface molecules gain enough energy to escape as gas.
What change of state occurs when a gas releases thermal energy and becomes a liquid?

Condensation. Loss of energy allows gas particles to come together as liquid.
Identify the state change when frost forms as water vapor turns directly into solid ice on a cold surface.

Deposition. Water vapor loses energy rapidly and forms solid ice crystals directly.
What happens to temperature during a phase change at constant pressure while thermal energy is added?

Temperature stays constant. Energy goes into breaking bonds, not raising temperature.
Identify the state change: water vapor cools and forms liquid droplets on a cold surface.

Condensation. Gas loses thermal energy to become liquid on cold surface.
Which process absorbs thermal energy from the surroundings: condensation or vaporization?

Vaporization absorbs thermal energy. Breaking liquid bonds requires energy input.
Which state change is occurring when frost forms as water vapor turns directly into ice?

Deposition. Water vapor loses energy and forms ice crystals directly.
What is the name of the state change from liquid to gas throughout the liquid at its boiling point?

Boiling. Rapid vaporization occurs throughout the liquid at high temperature.
Identify the state change when thermal energy is added and a solid becomes a liquid.

Melting. Energy input breaks solid's rigid particle arrangement.
Identify the state change when a liquid gains thermal energy and becomes a gas.

Vaporization (boiling/evaporation). Liquid gains energy to overcome intermolecular forces.
What change of state occurs when a liquid gains thermal energy and becomes a gas?

Vaporization. Particles gain enough energy to overcome liquid forces.
Which direction of thermal energy change causes freezing, condensation, and deposition?

Removing thermal energy (cooling). These transitions release energy as bonds form.
What form of energy change occurs during melting or boiling: change in temperature or change in state?

Change in state (latent heat). Energy breaks/forms bonds between particles rather than changing temperature.
Which state change requires removing thermal energy: condensation or vaporization?

Condensation. Gas to liquid releases heat; liquid to gas needs heat.
What happens to a liquid when thermal energy is removed until it reaches its freezing point?

It freezes: liquid changes to solid. Removed energy allows particles to lock into fixed positions.
What happens to temperature during a phase change while heat is still being added at constant pressure?

Temperature stays constant. Energy goes into breaking bonds, not increasing kinetic energy.
Which state of matter has particles far apart that move freely and fill the entire container?

Gas. High energy overcomes all intermolecular attractions.
Which state change requires adding thermal energy: freezing or melting?

Melting. Melting needs heat input; freezing releases heat.
Which state change is predicted when thermal energy is added to ice at $0\,^{\circ}\text{C}$ ?

Melting. At melting point, added energy causes solid to liquefy.
Identify the state change: A puddle disappears over time at room temperature.

Evaporation (liquid gas). Liquid water gains energy from surroundings and becomes vapor.
What is the phase change called when a solid becomes a liquid due to added thermal energy?

Melting. Adding thermal energy breaks bonds between particles in the solid.
What is the phase change called when a gas becomes a liquid because thermal energy is removed?

Condensation. Removing thermal energy causes gas particles to slow and bond together.
What change of state occurs when a liquid loses thermal energy and becomes a solid?

Freezing. Particles slow down and form ordered arrangements as energy is removed.
Which option best describes particle motion when thermal energy increases in a substance?

Particles move faster (higher average kinetic energy). Temperature is the average kinetic energy of particles.
What change of state occurs when a solid gains thermal energy and becomes a gas directly?

Sublimation. Particles gain enough energy to skip the liquid phase.
Which direction of thermal energy transfer is required for vaporization: gain or loss?

Gain of thermal energy. Breaking liquid attractions requires energy input.
Which state of matter has no definite shape and no definite volume?

Gas. Particles move freely and spread to fill any container.
Which option describes particle motion when thermal energy is added to a substance (no state change)?

Particles move faster (greater kinetic energy). Added energy increases particle vibration and movement.
What state change occurs when a solid gains thermal energy and becomes a liquid?

Melting. Solid particles gain energy to overcome forces and flow as liquid.
What is the phase change called when a solid becomes a gas without becoming a liquid first?

Sublimation. Direct solid-to-gas transition requires enough energy to skip the liquid phase.
What change of state occurs when a gas loses thermal energy and becomes a solid without liquefying?

Deposition (gas solid). Gas particles lose energy and form solid bonds directly.
Which direction of thermal energy change causes freezing, condensation, or deposition: absorbed or released?

Released. These transitions occur when particles lose kinetic energy.
Which direction of thermal energy change causes particles to move slower on average: added or removed?

Removed thermal energy. Less heat means less kinetic energy and slower motion.
What is the name of the state change from gas to liquid when thermal energy is removed?

Condensation. Gas particles lose energy and form liquid bonds.
What is the name of the phase change from solid to liquid when thermal energy is added?

Melting. Added thermal energy breaks bonds between particles in the solid structure.
What state change occurs when a gas loses thermal energy and becomes a solid without becoming liquid?

Deposition. Gas particles lose energy and form solid structure directly.
Identify the state change: a substance releases thermal energy and changes from gas to liquid.

Condensation. Releasing energy to go from gas to liquid is condensation.
What change of state occurs when a gas loses thermal energy and becomes a liquid?

Condensation: gas to liquid. Lost energy allows gas particles to stick together as liquid.
What happens to temperature during a phase change while thermal energy is being removed?

Temperature stays constant. Energy from bond formation doesn't change temperature during transition.
Identify the state change when water vapor loses thermal energy and becomes liquid water droplets.

Condensation. Gas loses energy and forms liquid droplets.
Identify the state change for water when thermal energy is added and it goes from liquid to gas.

Vaporization. Liquid water gains energy to become water vapor.
What happens to temperature during melting if thermal energy continues to be added at the melting point?

Temperature stays constant until melting finishes. All added energy breaks bonds, not raising temperature.
Which process releases thermal energy: condensation or vaporization?

Condensation releases thermal energy. Gas particles form bonds, releasing stored energy.
What happens to the state of matter when thermal energy is removed from a gas at its condensation point?

It condenses: gas changes to liquid. Lost energy slows particles enough to form liquid bonds.
What happens to particle kinetic energy (average speed) when thermal energy is added to a substance?

It increases. More thermal energy means faster particle movement.
What happens to temperature during a phase change while thermal energy is still being added?

Temperature stays constant at the melting/boiling point. Energy goes into breaking bonds, not raising temperature.
Which process releases thermal energy to the surroundings: condensation or vaporization?

Condensation. Gas to liquid releases heat; liquid to gas absorbs heat.
Which state change is most likely when thermal energy is removed from a gas: condensation or melting?

Condensation. Removing energy from gas typically forms liquid first.
Which state of matter has neither definite shape nor definite volume?

Gas. Particles move freely and fill any container completely.
Which direction of thermal energy change causes melting, vaporization, or sublimation?

Thermal energy increases (heat absorbed). Energy breaks bonds between particles in ordered states.
Identify the state change when water droplets form on the outside of a cold glass.

Condensation (gas to liquid). Cold surface removes energy from water vapor in air.
Identify the state change: frost forms on a window when water vapor turns directly into ice.

Deposition (gas solid). Water vapor loses energy rapidly, skipping liquid phase.
What is the phase change called when a liquid becomes a gas due to added thermal energy?

Vaporization (evaporation/boiling). Adding thermal energy allows liquid particles to escape as gas.
Which has higher average particle kinetic energy at the same substance: solid or liquid?

Liquid. Liquid particles move more freely and have more kinetic energy than solids.
What happens to particle spacing when a substance changes from solid to liquid?

Particles spread farther apart. Melting weakens bonds, letting particles move more freely.
Which option best describes energy change during freezing: releases energy or absorbs energy?

Releases energy to the surroundings. Particles form bonds and release stored potential energy.
What phase change occurs when a liquid loses thermal energy and becomes a solid?

Freezing. Cooling slows particles until they lock into fixed positions.
Identify the phase change: a cold soda can forms water droplets on the outside.

Condensation. Water vapor in air cools and becomes liquid on cold surface.
What change of state occurs when a solid gains thermal energy and becomes a gas directly?

Sublimation. High energy input breaks all bonds, skipping the liquid phase.
Which state of matter generally has the highest particle kinetic energy: solid, liquid, or gas?

Gas. Particles move freely with maximum kinetic energy.
What change of state occurs when a gas releases thermal energy and becomes a solid?

Deposition. Gas particles lose energy and form solid structure directly.
Which direction of thermal energy transfer is required for melting: gain or loss?

Gain of thermal energy. Breaking solid bonds requires energy input.
Identify what happens to temperature during melting at the melting point while heating continues.

Temperature stays constant. Energy goes into breaking bonds, not raising temperature.
What is the name of the phase change from liquid to solid when thermal energy is removed?

Freezing. Removing thermal energy allows particles to form rigid bonds.
Which direction of thermal energy change causes freezing, condensation, or deposition: added or removed?

Removed thermal energy. These transitions release energy as particles form stronger bonds.
Identify the state change: a substance absorbs thermal energy and changes from solid to liquid.

Melting. Absorbing energy to go from solid to liquid is melting.
Identify the state change when a puddle slowly disappears at room temperature.

Evaporation (liquid to gas). Surface molecules gain enough energy to escape as gas.
Which direction of thermal energy transfer is required for freezing: gain or loss?

Loss of thermal energy. Energy removal allows particles to form solid bonds.
Which state has the greatest particle kinetic energy: solid, liquid, or gas (for the same substance)?

Gas. Gas particles move fastest and have highest kinetic energy.
What is the most likely state at the lowest thermal energy: solid, liquid, or gas?

Solid. Particles have least kinetic energy in solid state.
Which state change requires adding thermal energy: deposition or sublimation?

Sublimation. Solid to gas requires heat; gas to solid releases heat.
What state change occurs when a liquid loses thermal energy until it becomes a solid?

Freezing (liquid solid). Removing thermal energy allows particles to form rigid bonds.
Which change in particle spacing occurs when a substance changes from liquid to gas?

Particles become much farther apart. Gas particles have much more space between them than liquids.
Choose the correct prediction: adding thermal energy to a gas most directly causes which change?

No phase change; gas temperature increases. Gases already have broken bonds, so energy increases particle motion.
What change of state occurs when a solid gains thermal energy and becomes a liquid?

Melting (solid liquid). Heat breaks bonds between particles, allowing them to move freely.
What happens to average particle kinetic energy when a substance is heated (temperature increases)?

It increases. Heat increases particle motion and kinetic energy.
What state change occurs when a gas loses thermal energy and becomes a liquid?

Condensation. Gas particles lose energy and attract to form liquid.
Identify the state change when dry ice changes directly into carbon dioxide gas.

Sublimation (solid to gas). Solid CO₂ particles gain energy to become gas directly.
What change of state occurs when a liquid loses thermal energy and becomes a solid?

Freezing (liquid solid). Cooling slows particles until they lock into fixed positions.
Identify the state change when thermal energy is removed from liquid water and it becomes ice.

Freezing. Water loses energy and molecules lock into ice's crystalline structure.
Identify the state change when thermal energy is removed and a liquid becomes a solid.

Freezing. Energy removal allows particles to form solid structure.
What change of state occurs when a solid absorbs thermal energy and becomes a gas?

Sublimation. Direct transition skips liquid phase with enough energy.
Which direction of thermal energy transfer is required for condensation: gain or loss?

Loss of thermal energy. Forming liquid bonds releases energy to surroundings.
What change of state occurs when a gas loses thermal energy and becomes a solid directly?

Deposition. Gas particles lose energy and form solid bonds directly.
Which direction of thermal energy change causes particles to move faster on average: added or removed?

Added thermal energy. Heat increases kinetic energy and particle motion.
Identify the particle-level change when a gas condenses: particle spacing increases, or decreases?

Particle spacing decreases. Gas particles come closer together when forming liquid.
What state change occurs when a solid gains thermal energy and becomes a gas without becoming liquid?

Sublimation. Solid particles gain enough energy to escape directly to gas.
Identify the state change: liquid water gains thermal energy and becomes water vapor.

Vaporization. Liquid gains thermal energy to become gas.
Choose the state change: A solid air freshener slowly disappears without forming a liquid.

Sublimation: solid to gas. Particles gain enough energy to escape solid directly.
Identify the state change when dry ice gains thermal energy and turns directly into carbon dioxide gas.

Sublimation. Solid CO₂ gains energy to become gas without melting.
Which phase change is occurring if a substance is cooling and its particles become more ordered?

Freezing. Cooling and ordering particles indicates liquid becoming solid.
Identify the state change when liquid water gains thermal energy and becomes water vapor.

Vaporization. Liquid gains energy to overcome intermolecular forces.
What state change occurs when a solid gains thermal energy and becomes a gas without becoming liquid?

Sublimation (solid gas). Direct transition occurs when solid particles gain enough energy to escape.
Identify the particle-level change when a solid melts: particle speed increases, or decreases?

Particle speed increases. Particles gain kinetic energy and move faster when melting.
Which state change is exothermic (releases thermal energy): condensation or vaporization?

Condensation is exothermic. Energy is released when gas particles form liquid bonds.
Which direction of thermal energy transfer is required for condensation: gain or loss?

Loss of thermal energy. Energy removal causes gas particles to form liquid.
What change of state occurs when a liquid absorbs thermal energy and becomes a gas?

Vaporization (evaporation or boiling). Energy overcomes intermolecular forces holding liquid together.
Which state change is occurring if frost forms from water vapor on a cold window?

Deposition (gas to solid). Water vapor loses energy and forms solid ice crystals.
Which direction of thermal energy transfer causes gas to become liquid: gain or loss of thermal energy?

Loss of thermal energy. Gas particles must lose energy to form closer liquid bonds.
What change of state occurs when a liquid gains thermal energy and becomes a gas?

Vaporization (evaporation/boiling). Heat gives particles enough energy to escape liquid attractions.
What is the term for energy transferred due to a temperature difference between objects?

Heat. Heat is thermal energy in transit between objects.
What phase change occurs when a gas loses thermal energy and becomes a liquid?

Condensation. Cooling slows gas particles until they stick together as liquid.
Identify the state change: a substance absorbs thermal energy and changes from liquid to gas.

Vaporization. Absorbing energy to go from liquid to gas is vaporization.
Choose the correct prediction: removing thermal energy from a liquid causes melting, freezing, or boiling?

Freezing. Removing energy from liquid causes it to solidify.
Identify the state change: Frost forms on a window when air is very cold.

Deposition (gas solid). Water vapor loses energy to cold air and forms ice crystals directly.
What happens to temperature during a phase change while thermal energy is being removed?

Temperature stays constant at the freezing/condensation point. Energy released from bond formation doesn't change temperature.
Identify the state change: an ice cube absorbs heat and becomes liquid water.

Melting. Solid gains thermal energy to become liquid.
What is the name of the state change from liquid to solid when thermal energy is removed?

Freezing. Removing thermal energy allows particles to form rigid bonds.
Which option best describes energy use during melting: increases kinetic energy or breaks attractions?

Breaks attractions (increases potential energy). Energy overcomes forces holding particles in solid structure.
Choose the state change: Frost forms on a window when humid air contacts a surface below $0\,^{\circ}\mathrm{C}$ .

Deposition: gas to solid. Water vapor loses energy and forms ice crystals directly.
What is the name of the phase change from gas directly to solid when thermal energy is removed?

Deposition. Gas particles lose energy and form solid bonds directly.
What is the name of the phase change from solid to liquid when thermal energy is added?

Melting. Heat breaks bonds between particles in fixed positions.
What is the term for the average kinetic energy of particles in a substance?

Temperature. Measures how fast particles are moving on average.
Which state of matter has a definite volume but takes the shape of its container?

Liquid. Particles flow past each other but stay close together.
Which state change is endothermic (requires absorbing thermal energy): melting or freezing?

Melting is endothermic. Energy must be absorbed to break solid bonds.
What happens to temperature during boiling if thermal energy continues to be added at the boiling point?

Temperature stays constant until boiling is complete. Energy converts liquid to gas, not raising temperature.
Which direction of thermal energy transfer is required for vaporization: gain or loss?

Gain of thermal energy. Energy input allows particles to escape liquid state.
What is the name of the energy absorbed or released during a phase change at constant temperature?

Latent heat. Energy absorbed/released during phase transitions.
Identify the state change when a solid air freshener slowly turns directly into gas at room temperature.

Sublimation. Solid particles gain enough energy to escape directly as gas.
Which state change occurs when thermal energy is removed and particles move closer together: melting or freezing?

Freezing. Energy removal slows particles, allowing them to bond in fixed positions.
What happens to temperature during a phase change while thermal energy is still being added?

Temperature stays constant. Energy goes into breaking/forming bonds, not raising temperature.
What is the name for thermal energy absorbed or released during a phase change without temperature change?

Latent heat. Hidden heat used for phase transitions, not temperature change.
Which process absorbs thermal energy: melting, freezing, or condensation?

Melting absorbs thermal energy. Energy is needed to break bonds between solid particles.
What happens to average particle kinetic energy during a phase change at constant temperature?

It stays constant. Energy goes into breaking bonds, not increasing particle motion.
Which direction does thermal energy flow: from higher temperature to lower temperature, or the reverse?

From higher temperature to lower temperature. Heat flows spontaneously from hot to cold regions.
Which state of matter has a definite volume but takes the shape of its container?

Liquid. Particles can flow but remain close together.
What change of state occurs when a gas loses thermal energy and becomes a liquid?

Condensation. Particles lose energy and intermolecular forces pull them together.
What state change occurs when a liquid gains thermal energy and becomes a gas?

Vaporization. Liquid particles gain enough energy to escape into gas phase.
Identify the state change when frost forms on a window without liquid water present.

Deposition (gas to solid). Water vapor loses energy and forms ice crystals directly.
What state change occurs when a gas loses thermal energy and becomes a solid without becoming liquid?

Deposition (gas solid). Gas particles lose energy and form solid bonds directly.
Identify the state change when dry ice turns directly into carbon dioxide gas.

Sublimation. Solid $CO_2$ transitions directly to gas, skipping liquid phase.
Which state change requires removing thermal energy: melting or freezing?

Freezing. Liquid to solid releases heat; solid to liquid needs heat.
Which state of matter has a definite shape and definite volume?

Solid. Particles are tightly packed in fixed positions.
What state change occurs when a gas loses thermal energy until it becomes a liquid?

Condensation (gas liquid). Lost energy allows gas particles to come together and form liquid bonds.
Identify the state change: water droplets form on the outside of a cold glass.

Condensation (gas to liquid). Water vapor loses energy to cold glass and forms liquid.
What is the name of the state change from gas directly to solid when thermal energy is removed?

Deposition. Gas particles lose energy and form solid bonds directly.

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