States of Matter
A state of matter with a definite shape AND definite volume.
What is a solid?
The change from a solid directly to a gas without becoming a liquid.
What is sublimation?
A graph showing temperature change as thermal energy is added.
What is a heating curve?
What causes gas pressure?
Particles colliding with the walls of the container.
Which gas law compares pressure and volume?
Boyle's Law
This state of matter has a definite volume but takes the shape of its container.
What is a liquid?
The change from a gas directly to a solid. (ex: frost forming)
What is deposition?
The flat section of a heating/cooling curve where a phase change occurs.
What is a phase-change plateau?
The temperature scale used in gas-law calculations.
What is Kelvin?
The energy an object or particle has because of its motion.
What is kinetic energy?
These particles are far apart, move rapidly and randomly, and fill their container.
What are gas particles?
Name the six phase changes and whether each absorbs or releases energy
Melting (absorb), Freezing (release), Vaporization (absorb), Condensation (release), Sublimation (absorb), Deposition (release).
On a cooling curve, what happens during the flat sections?
A phase change occurs, energy is released, and temperature stays constant.
A relationship where one variable increases while the other decreases.
What is an inverse relationship?
A water molecule is still a water molecule whether it is ice, liquid, or vapor. What changes between states?
The particle arrangement, spacing, motion, and attractions change—not the particle itself.
Explain why a liquid can flow but a solid cannot, using particle motion.
Liquid particles slide past one another; solid particles are locked in fixed positions and only vibrate.
Explain the difference between evaporation and boiling.
Evaporation occurs only at the surface and can happen below the boiling point; boiling occurs throughout the liquidwith vapor bubbles forming.
List the five stages of a typical heating curve in order.
Heating the solid → Melting → Heating the liquid → Boiling → Heating the gas.
Explain why pressure increases when a gas is heated in a sealed, fixed-volume container.
Particles gain kinetic energy, move faster, and hit the walls more often and with greater force.
Two factors that make evaporation happen faster.
Higher temperature, greater surface area, more air movement, or lower humidity (any two).
Use the particle model to explain why gases are easier to compress than solids or liquids.
Gas particles are far apart with lots of empty space, so they can be pushed closer together; solid/liquid particles are already packed tightly.
Explain why temperature remains constant during melting even though energy is being added.
Added energy is used to change particle arrangement, increase spacing, and overcome attractions—not to increase average kinetic energy.
During the sloped sections of a heating curve, what is happening to particles and kinetic energy?
Temperature and average kinetic energy increase; particles move faster but the substance stays in one state.
Design an explanation: Why does a balloon expand when heated but shrink when cooled?
Heating increases particle speed and collisions; the gas expands to keep pressure constant (Charles's Law). Cooling slows particles, so volume decreases.
Which gas law compares temperature and pressure at constant volume?
Gay-Lussac's Law