Which state of matter has particles in a fixed, tightly packed arrangement?
Solid.
What is the change from a liquid to a gas called?
Vaporization (evaporation/boiling).
What form of energy is related to the motion of particles?
kinetic energy.
Which state of matter takes the shape of its container but keeps a constant volume?
Liquid.
What is the change from a gas directly into a solid called?
Deposition.
As you heat a solid, what happens to particle motion?
It increases — particles vibrate faster.
Which state of matter has particles far apart, moving freely in all directions?
Gas.
What is the change from a solid directly into a gas called?
Sublimation.
What is the temperature at which a solid changes to a liquid called?
Melting point.
Describe how particle spacing changes from solid to liquid to gas.
Spacing increases — closest in solids, farther apart in liquids, farthest apart in gases.
What happens to temperature while a substance is melting?
It stays constant until melting is complete.
Two containers of water are the same temperature, but one has twice the mass. Which has more thermal energy?
The one with twice the mass, even at the same temperature.
Why can gases be compressed much more easily than solids or liquids?
Gas particles have large empty spaces between them that can be pushed together, unlike tightly packed solids/liquids.
Why doesn't temperature rise during a phase change even though heat is still added?
The energy breaks/rearranges bonds between particles instead of speeding them up, so kinetic energy (temperature) stays the same until the change finishes.
Explain the difference between temperature and thermal energy.
Temperature is average kinetic energy of particles; thermal energy is total kinetic energy of all particles, depending on both temperature and amount of matter.