1. Chapter 4A: Physical Behavior of Matter

2. Aim: To examine the solid, liquid, and gaseous phases of matter
To learn how to calculate the heat exchanged during heating, cooling, and phase changes

3. Phases of Matter
An element, compound, or mixture may exist in 3 different forms.
They may be in:
Solid
Liquid
Gas

4. What Defines a Solid Held in a rigid form Definite shape and volume
VERY STRONG attractive forces
Definite shape and volume
Particles in fixed positions
Can vibrate but not move
Crystalline structure

5. What Defines a Liquid? Not as rigid
Definite volume, but takes the shape of the container
Sufficient attractiveness to have a definite volume
Particles are close to each other and can slide past each other
No regular pattern or arrangement of particles

6. What Defines a Gas? No definite volume and no definite shape
Minimal attractive forces
Particles are very far apart
Gases spread out indefinitely
Fill the volume of the container
Vapor is a gaseous form of a substance that is normally a liquid or solid form

7. Heating Curves

8. A few Definitions:
Temperature- measure of the average KINETIC ENERGY of a substance
Kinetic Energy- “moving” energy
So, increasing the temperature means you are increasing the movement of the particles
Potential Energy- stored energy
So, phase changes
Heat of Fusion- amount of heat required to convert a solid to a liquid
Melting (fusion) is the reverse of freezing
Heat of Vaporization- amount of heat required to convert a liquid to a gas
Vaporization is the reverse of condensation

9. Heating Curves
Either the temperature is changing or the phase is changing. NOT BOTH
What Happens:
Ice is absorbing kinetic energy so temp is rising
Ice is melting. The potential energy increases because the heat is being used to break the bonds and cause the phase change. Heat of Fusion.
Water is absorbing kinetic energy so temp is rising
Water is boiling. The potential energy increases because the heat is being used to break the bonds and cause the phase change. Heat of Vaporization.
Gas is absorbing kinetic energy so temp is rising
As you go up, energy is absorbed. (It feels HOT)
As you go down, energy is released. (It feels COOL)

10. Heating Curves
So, as the graph is going up, the temperature is changing
The heat being added is adding to the average kinetic energy (temperature)
But, the phase stays the same
As the graph plateaus, the phase is changing
The heat being added is melting the ice/ vaporizing the liquid (phase change)
But, the temperature is staying the same

12. Heating Curves
As the graph goes up, it is ENDOTHERMIC because it is absorbing energy
As the graph goes down, it is EXOTHERMIC because it is releasing energy

13. Special Circumstances
Sublimation:
When a solid phase changes to a gas and skips the liquid phase
CO2(s)
Dry Ice
Deposition
Formation of frost

14. Open your workbook to p. 60 (1-16)
4- solid
1- only solid
1- gas 2
2- gas
3- solid
3- s => g
2- s => g
1- all water 2
3- B => E 4 1
4- going up
2- going down

15. Energy Defined as the ability to do work Measured in Joules (J)
Table T and Table B
There are many different forms of energy
Energy cannot be created nor destroyed, but can be converted from one form to another

16. What are some types of energy?
Chemical
Released or absorbed in a chemical reaction
Electrical
Flow of electrons
Electromagnetic Radiation
Energy made up of waves
Mechanical
Energy of moving objects
Nuclear
Energy given off when a nucleus breaks up into smaller nuclei or vice versa
Heat (thermal)
Random motion of atoms and molecules

17. What is Thermal Energy? Heat Energy
Heat always flows from hotter body to the cooler body
It flows from the object that has MORE energy to the object that has LESS energy
From the HURT LEG to the ICE PACK
From the WATER to the ICE in the glass

18. Temperature Measured with a thermometer
Measure of the average kinetic energy of the molecules
More movement = higher temperature
More movement = more space between the particles
Solids- particles are next to each other, touching
Gases- particles are spread out
Units are Celsius (oC) and Kelvin (K)
Kelvin = Celsius (Table T)
Direct scaled between them.
So, an increase of 5oC is an increase of 5K

19. Convert the following:
0oC to Kelvin
0K to Celsius
-10oC to Kelvin
300K to Celsius

20. Open your workbook to p. 63 (17-29)4 1 3 1 3
3 (increase of 10o)

21. Measurement of Heat Energy
Amount of heat given off or absorbed in a reaction
Table T and Table B
Calorimeter
q = mCDT
q = ?
m = ?
C = ?
D = ?
T = ?

22. Let’s Do an Example…
A 7.00 gram sample of water is heated and the temperature rises from 10.0oC to 15.0oC. What is the total amount of heat energy absorbed by the water?
q = ?
m = ?
C = ?
T1 = ?
T2 = ?
D = ?

23. Answer q = mCDT q = ? m = 7.00 grams C = 4.18 J/g * oC T1 = 15.0
T2 = 10.0 oC
D = 5.0 oC
q = (7.00g) (4.18 J/g * oC) (5.0oC)
q = 146 J

24. One More Example…
The temperature of grams of water was increased by 3.00oC. How much heat energy was absorbed by the water?
q = ?
m = ?
C = ?
T1 = ?
T2 = ?
D = ?

25. Answer q = mCDT q = ? m = 15.00 grams C = 4.18 J/g * oC T1 = ? T2 = ?
D = 3.00 oC
q = (15.00g) (4.18 J/g * oC) (3.00oC)
q = 188 J

26. Heat of Fusion
q = mHf
Table T
Amount of heat required to convert a unit of mass from a solid to a liquid (or a liquid to a solid)
For solid water at 0oC and 1atm is 334J/g
Table B
Increases the potential energy without increasing the kinetic energy
So, remember, no change in temperature!

27. Heat of Vaporization q = mHv
Table T
Amount of heat required to convert a unit of mass from a liquid to a gas (or a gas to a liquid)
For solid water at 100oC and 1atm is 2260J/g
Table B
Increases the potential energy without increasing the kinetic energy
So, remember, no change in temperature!

28. Let’s do an Example q = mHf
How many joules are required to melt 255g of ice at 0oC?

29. Let’s do an Example q = mHv
How many joules of energy are required to vaporize 423g of water at 100oC and 1atm?

30. Open your book to p (30-46) D d D d

31. STUDY for your TEST!!!!