1. Chapter 8 Material on Midterm
States of Matter
Chapter 8
Material on Midterm

2. Section 1: Solids, Liquids, and Gases
What are states of matter?
The States of matter are the physical forms in which a substance can exist
Solid
Liquid
Gas
Plasma is a fourth state of matter that is positively and negatively charged particles
Most common in universe

3. Section 1: Solids, Liquids, and Gases
Particles of matter
Matter is made of small particles called atoms and molecules
Always on the move
How they interact with each other determines their state of matter

4. Section 1: Solids, Liquids, and Gases
What is a solid?
A solid is the state of matter that has a definite shape and volume
Particles smooshed together
Can only vibrate—stuck in place

5. Section 1: Solids, Liquids, and Gases
Types of solids
Crystalline solids have a orderly, 3D arrangement in a repeating pattern
Ice, diamond, iron
Amorphous solids have no special arrangement
Glass, rubber, wax

6. Section 1: Solids, Liquids, and Gases
What is a liquid?
A liquid is the state of matter that has a definite volume but takes the shape of its container
Little space in between particles
Can slide past another

7. Section 1: Solids, Liquids, and Gases
Liquid characteristics
Surface tension is an uneven force that acts on the particles at the surface of a liquid
Viscosity is a measurement of a liquid’s resistance to flow

8. Section 1: Solids, Liquids, and Gases
What is a gas?
A gas is the state of matter that has no definite shape or volume
Molecules move super fast
Not really held together at all
Vapor is the gas state of a substance that is normally a solid or liquid at room temperature

9. Section 1: Solids, Liquids, and Gases
State of Matter
Definite Shape?
Definite Volume?
Solid
Liquid
Gas

10. Section 2: Changes in State
A change of state is the change of a substance from one physical form to another

11. Section 2: Changes in State
Changes of state are cause by changes in energy
Kinetic energy is the energy an object has due to its motion
We can measure the average kinetic energy of all the particles in an object—the true definition of temperature

12. Section 2: Changes in State
Changes of state are cause by changes in energy
Potential energy is the stored energy due to interactions between particles or objects
Solids have the least potential energy because their particles are so close
Gases have the most potential energy because their particles are spread

13. Section 2: Changes in State
Thermal energy is total potential and kinetic energies of an object.
We can either add or remove energy to get changes of state
If we add, we call it endothermic
If we remove, we call it exothermic

14. Section 2: Changes in State
The six changes of state
Melting (SL)
Freezing (LS)
Vaporization (LG)
Condensation (GL)
Sublimation (SG)
Deposition (GS)

15. Section 2: Changes in State
Melting is the change of state from a solid to a liquid
Adding energy to a solid increases its energy
Particles move faster, move away from each other
The melting point is the temperature at which a substance changes from a solid to a liquid
Item
Melting temperature (C)
State of matter at room temperature (25C)
Water
0 C
Table salt
801 C
Nitrogen
-210 C…-159C boiling

16. Section 2: Changes in State
Freezing is the change of state from a liquid to a solid
We remove energy—molecules slow down
The freezing point is the temperature at which this happens

17. Section 2: Changes in State
Vaporization is the change of a substance from a liquid to a gas
We add energy—molecules speed up
Evaporation is vaporization that occurs only at the surface of a liquid
Boiling is the change of a liquid to a gas (vapor) throughout the whole liquid

18. Section 2: Changes in State
Condensation is the change of state from a gas to a liquid
We remove energy—molecules slow down
Condensation point is the temperature at which a gas becomes a liquid
Same as boiling point

19. Section 2: Changes in State
Sublimation is the change of state from which a solid changes into a gas without going through a liquid state
We add a LOT of energy—molecules speed up a lot
Dry ice
Deposition is the change of state from a gas to a solid without going through the liquid state
We remove a LOT of energy—molecules slow down a lot
Frost

20. Section 2: Changes in State
Change of temperature versus change of state
When energy is added…
Either the temperature changes
OR the state changes
Not both!

21. Section 2: Changes in State

22. Section 2: Changes in State
When you add heat to a solid…
…the temperature increases until the melting point
You still add heat…
…the temperature stays while the solid melts
You now add heat to a liquid…
…the temperature increases until the boiling point
…the temperature stays while the liquid vaporizes
You now add heat to a gas…
…the temperature will just keep increasing!

23. Section 2: Changes in State

24. Section 2: Changes in State

25. Section 2: Changes in State
State change
Starting state
Ending state
Energy added or removed
Endothermic or exothermic
Melting
Freezing
Evaporation
Condensation
Sublimation
Deposition

26. Section 3: The Behavior of Gases
The kinetic molecular theory is an explanation of how particles in matter behave
Small particles make up all matter
Particles are in constant, random motion
Particles collide with other particles, other objects, an the walls of their container
No energy is lost when particles collide
We will focus on these factors in gases

27. Section 3: The Behavior of Gases
What factors affect how gases behave?
Temperature
Volume
Pressure

28. Section 3: The Behavior of Gases
Temperature
Temperature is a measure of how fast the particles in an object are moving
The faster the particles move, the more energy they have
Increase temperature….increase pressure
Increase temperatures…increase volume

29. Section 3: The Behavior of Gases
Volume
Volume is the amount of space that an object takes up
Volume of a gas depends on its container
Decrease volume…increase pressure…pop!
Increase volume…decrease pressure

30. Section 3: The Behavior of Gases
Pressure
Pressure is the amount of force applied per unit area
The more particles…the more pressure

31. Section 3: The Behavior of Gases

32. Section 3: The Behavior of Gases
Gas behavior laws
Boyle’s Law
Involves volume and pressure
Charles’s Law
Involves temperature and volume
Guy-Lussac’s Law
Involves temperature and pressure

33. Section 3: The Behavior of Gases
Boyle’s Law
Volume (L)
Pressure (Pa)
500
100
300
150
225
200
175
250
125
350
112
400
450

34. Section 3: The Behavior of Gases
What is Boyle’s Law?
Boyle’s Law states that pressure of a gas increases if the volume decreases and pressure of a gas decreases if the volume increases, when temperature is constant
Inverse = opposite relationship
So…
As pressure increases, volume decreases
As pressure decreases, volume increases

35. Section 3: The Behavior of Gases
Charles’s Law
Volume (L)
Temperature (°C) 10 80 20
160 30
240 40
320 50
400 60
480

36. Section 3: The Behavior of Gases
What is Charles’s Law?
Charles’s Law states that for a fixed amount of gas at a constant pressure, the volume of gas changes in the same way that the temperature changes
So…
As temperature increases, volume increases
As temperature decreases, volume decreases

37. Section 3: The Behavior of Gases
Guy Lussac’s Law
Volume constant
Volume constant

38. Section 3: The Behavior of Gases
What is Guy Lussac’s Law?
Guy Lussac’s Law states that for a fixed amount of gas at a constant volume, the pressure of gas changes in the same way that the temperature changes
So…
As temperature increases, pressure increases
As temperature decreases, pressure decreases