Name That Phase Change!
This phase change happens when a solid gains heat and becomes a liquid.
Melting
In which state of matter do particles vibrate in place?
Solid
On a heating curve, a slanted line means the temperature is doing this.
Increasing
During which phase changes is energy added to the substance?
Melting, evaporation, and boiling.
Water droplets forming on a cold soda can is an example of this phase change.
Condensation
Fog on a bathroom mirror is an example of this gas → liquid change.
Condensation
When a liquid freezes, particles move _______, and energy is _________.
When a liquid freezes, particles move closer, and energy is removed.
A flat line on a heating curve means this is happening.
A phase change
During which phase changes is energy removed from the substance?
When butter melts on a hot pan, energy is being (added or removed?).
Added
Puddles disappearing after a sunny day is an example of this slow liquid → gas change.
Evaporation
During melting, particle motion ________ ___.
Speeds up
The first flat line on a heating curve represents this phase change.
Melting (solid -> liquid)
When a gas becomes a liquid, what happens to the energy in the substance?
Energy is released (removed)
Describe what happens to particle motion when a puddle evaporates.
Particles speed up and spread apart into a gas
This fast process turns a liquid into a gas throughout the entire substance, forming bubbles.
Boiling
Gas particles move this way compared to solids and liquids.
Fastest and far apart
The temperature stays the same during boiling because the added energy increases this type of energy.
Potential Energy
Why does evaporation require energy to be added?
Particles need energy to escape the liquid's surface and spread out into a gas.
Explain why boiling requires more energy than evaporation.
Boiling happens throughout the whole liquid and needs more heat to create bubbles
Water forming ice cubes in the freezer is an example of this liquid → solid change.
Freezing
Temperature stays the same during a phase change because energy is being used to change this.
The state of matter (potential energy)
What two factors determine the height of the “boiling” flat line on a heating curve?
Substance type and boiling point temperature
Explain why the temperature stays the same during melting even though energy is going in.All added energy is used to change the state (break particle bonds), not increase temperature
All added energy is used to change the state (break particle bonds), not increase temperature
Ice and liquid water stay at 0°C during melting/freezing because the energy is used for this process instead of raising temperature.
Phase Change