States and Particles
What do we call the tiny pieces that make up all matter?
Particles
What is the name of the phase change when a solid turns into a liquid?
Melting
When you heat matter, do its particles move faster or slower?
Faster
What is mass?
How heavy something is/ how many particles it has.
Which temperature scale used in the unit sets water’s freezing point at 0 and boiling point at 100?
Celsius
Name the state of matter with particles very close together that vibrate in place and has a fixed shape.
Solid
What term describes a liquid changing into a gas?
Evaporation
When a substance is cooled it gets smaller. What is this called? Expansion or contraction?
Contraction.
What is volume?
The amount of space something takes up.
If the temperature goes from 20C to 70C what happens to the liquid in a thermometer?
It goes up/ expands
Which state of matter has particles that are farther apart, move quickly, and can be compressed?
Gas
What is condensation?
Condensation is when a gas becomes a liquid
How does cooling affect particle motion (speed) and spacing?
Cooling slows particles down and they move closer together.
During a phase change (ice melting to water), what happens to mass?
Stays the same.
How does a liquid thermometer show temperature changes?
The liquid expands when heated and moves up the narrow tube; it contracts and moves down when cooled.
Describe how particles in a liquid move compared to those in a solid.
Particles in a liquid are farther apart than in a solid and can slide past each other.
What is sublimation?
Sublimation is when a solid turns directly into a gas.
Describe what happens to the attractive forces between particles and the space between particles when heat is added.
Attractive forces decrease (weaken) and space between particles increases.
Give one example where volume changes but mass stays the same.
any phase change
Why does ice float on liquid water?
Ice is less dense than liquid water because the crystalline structure spaces molecules further apart, so ice floats.
What is the fourth state of matter that we did not focus on in class?
Plasma
List the six phase changes between solids, liquids, and gases described in the unit.
Melting, Freezing, Boiling (Vaporization), Condensing, Sublimation/Deposition
What happens to the particles in a gas when it is heated?
Particles move even faster and further apart.
A full water bottle was frozen and cracked. Explain.
Water expands as it freezes because ice forms a crystalline structure that spaces molecules farther apart.
Explain one engineering problem caused by temperature changes and one design solution engineers use to handle it.
Roads and bridges crack or deform from expansion/contraction. Solution: Use expansion joints, choose materials with suitable thermal properties, or allow movement in design.