1. Properties of Matter
Chapter 2

2. How do you identify matter?
We identify matter by its properties
How it taste, looks,and feels
Its size, shape, and color

3. Properties of Matter Video Clip

4. How can we identify physical properties?
Physical properties are those that we can determine without changing the identity of the substance we are studying.
Stretching a rubber band does not change how it looks before and after it is stretched!

5. Examples of physical properties:
The physical properties of sodium metal can be observed or measured. It is a soft, lustrous, silver-colored metal with a relatively low melting point and low density.
Hardness, color, melting point and density are all physical properties.

6. What is a physical change?
A physical change occurs when the substance changes state but does not change its chemical composition. For example: water freezing into ice, cutting a piece of wood into smaller pieces, etc. The form or appearance has changed, but the properties of that substance are the same (i.e. it has the same melting point, boiling point, chemical composition, etc.)
Definition of physical changes.

7. Characteristics of Physical Changes
Melting point
Boiling point
Vapor pressure
Color
State of matter
Density
Electrical conductivity
Solubility
Absorption to a surface
Hardness
Physical changes are characterized by the following:

8. DENSITY Q) Which weighs more: A kilogram of feathers
or a kilogram of iron?

9. Density is the Mass per unit Volume
What is Density?
If you take the same volume of different substances, then they will weigh different amounts.
Wood
Water
Iron
1 cm3
1 cm3
1 cm3
IRON
0.50 g
1.00 g
8.00 g
Q) Which has the greatest mass and therefore the most dense?
Density is the Mass per unit Volume

10. Density Equation: = m V m V  Mass Density = Volume Example:
g or kg m V 
Mass
Density =
Volume
g/cm3 or kg/ml
cm3 or ml
= m V
Example:
Q) Liquid water has a density of 1000kgm-3, while ice has density of 920kgm-3.
Calculate the volume occupied by 0.25kg of each.
V = m = 0.25 = m3 
V = m = 0.25 = m3 

11. DENSITY OF A REGULAR SOLID
Find the Mass of the solid on a balance.
Measure the three lengths and calculate the Volume.
(ie V = l x w x h )
Calculate the Density.
m = 240 g
2.0 cm
 = m = 240 =10.0 g/cm3 V
3.0 cm
4.0 cm

12. Material
Mass
in g
Length
in cm
Width
Height
Volume
in cm3
Density
in g/cm3

13. DENSITY g/cm3 Aluminium 2.70 Iron 7.86 Brass 8.50 Wood 0.50 Slate 2.80
Glass
2.50
Lead
11.3
Marble
2.70
Wax
0.89

14. DENSITY OF AN IRREGULAR SOLID
m = 360 g
 = m = 360 =12.0 g/cm3 V
Find the Mass of the solid on a balance.
Fill the Measuring Cylinder with Water to a known Volume.
Add the Object.
Work out the Volume of Water that is displaced.
Calculate the Density.
80 cm3
50 cm3

15. DENSITY OF AN IRREGULAR SOLID
OR use a Eureka Can to find the Volume.
Find the mass of the solid on a balance.
Add water until just overflowing.
Place a Measuring Cylinder under the spout.
Add the Object.
Collect the Water and read off the Volume.
Calculate Density
m = 440 g
40.0 cm3
 = m = 440 =11.0 g/cm3 V

16. DENSITY g/cm3 Aluminium 2.70 Iron 7.86 Brass 8.50 Wood 0.50 Slate 2.90
Glass
2.50

17. DENSITY OF A LIQUID Find the Mass of an empty Measuring Cylinder.
Mass of Liquid = Mass of Measuring Cylinder and Liquid – Mass of empty Measuring Cylinder
DENSITY OF A LIQUID
Find the Mass of an empty Measuring Cylinder.
Add a certain Volume of Liquid.
Find the Mass of the Measuring Cylinder and Liquid
Calculate the Mass of Liquid.
How?
Calculate Density of Liquid.
45.0 g
25.0 g
20.0 cm3
45 – 25 = 20 g
 = m = 20 =1.00 g/cm3
V 20

18. Mass of empty Measuring Cylinder
Liquid
Mass of empty Measuring Cylinder
in g
Mass of Measuring Cylinder and Liquid
Mass of Liquid
Volume
in cm3
Density
in g/cm3

19. DENSITY OF A GAS
Remove the air from a flask of a known Volume, using a vacuum pump.
Find its Mass.
Add the gas to be tested.
Reweigh.
The difference is the Mass of gas.
Calculate Density.
To vacuum flask
150.0 g
170.0 g
1000 cm3
= 20.0g
 = m = 20 = g/cm3 V

20. What are chemical properties?
Chemical properties describe the way a substance can change or react to form other substances. These properties, then, must be determined using a process that changes the identity of the substance of interest.

21. How can chemical properties be identified?
One of the chemical properties of alkali metals such as sodium and potassium is that they react with water. To determine this, we would have to combine an alkali metal with water and observe what happens.
In other words, we have to define chemical properties of a substance by the chemical changes it undergoes.

22. What are chemical changes?
A chemical change occurs when a substance changes into something new. This occurs due to heating, chemical reaction, etc. You can tell a chemical change has occurred if the density, melting point or freezing point of the original substance changes. Many common signs of a chemical change can be seen (bubbles forming, mass changed, etc).
Definition of chemical change.

23. Characteristics of Chemical Changes
Reaction with acids
Reaction with bases (alkalis)
Reaction with oxygen (combustion)
Ability to act as oxidizing agent
Ability to act as reducing agent
Reaction with other elements
Decomposition into simpler substances
Corrosion
Chemical Changes are characterized by the following:

24. Signs of a Chemical Change
Production of an odor
Change in temperature
Change in color
Formation of bubbles
Formation of a solid

25. Comparison of Physical and Chemical Properties

26. Chemical and Physical Properties Video Clip

27. Physical Changes of State
Chapter 2: Section 2
Physical Changes
of State

28. Phase Changes Video Clip

29. Changes of State
melting
boiling
solid
liquid
gas
freezing
condensing

30. Changes in State (phase changes)
1. Melting - solid to liquid
a. Particles get more kinetic energy and begin rotating around each other.
b. There isn’t enough energy to break the inter-particular attractions, so the particles remain close (liquid).
c. The energy required to melt a solid is called the heat of fusion.

31. 2. Freezing - liquid to solid
a. Particles lose kinetic energy
and slow down.
b. Attractive forces between particles become stronger than the particles’ motion, so the particles begin merely vibrating in place.
c. The amount of heat the particles must lose to turn into a solid is called the heat of fusion.

32. 3. Vaporization - liquid to gas
a. Types:
1) Boiling - rapid; gas bubbles are produced throughout.
2) Evaporation - slow; occurs at the surface.
b. Liquid particles gain enough kinetic energy to overcome forces between the particles and they begin translational motion; this energy is called the heat of vaporization.

33. 4. Evaporation is a cooling process.
a. Particles in a liquid gain kinetic energy.
b. They leave as gas particles (taking the energy away with them).
c. This leaves less energy in the liquid, therefore cooling down what is left.

34. Changes of state – heating curve
boiling 
condensing
liquid  gas
gas
temperature
liquid
melting 
freezing
solid  liquid
solid
time

35. 5. Sublimation - solid to gas or gas to solid
a. Dry ice - carbon dioxide
b. Iodine
c. Frost
6. During phase changes there is no change of temperature.

36. 7. Condensation - gas to liquid
a. Particles lose kinetic energy, slow down, and come closer together.
b. Inter-particular forces become strong enough to make particles merely rotate around each other.
c. The energy they lose to turn into a liquid is the heat of vaporization.

37. Changes of state – cooling curve activity

38. Changes of state activity

39. Properties Used to Identify Substances
Chapter 2: Section 3
Properties Used to Identify Substances

40. Properties Used to Identify Substances
1. Density- mass per unit of volume 2. Heating Properties- measure the rate at which substances conduct heat Example: iron and aluminum are used in pots and pans

41. 3.Solubility- how much a substance dissolves in a given volume of liquid 4. Electric Properties- how electrical charges are allowed to pass through Magnetic Properties- how substances are attracted to magnets

42. Techniques for Separating Solutions:
#1. Evaporation: changing from a liquid to vapor state– leaves behind the other component.
Example: Water mixed with sugar can be heated until the water evaporates and leaves the sugar behind.

43. Process used to drive vapor from liquid by heating
#2. Distillation:
Process used to drive vapor from liquid by heating
Great for separating two or more liquids which have different boiling points.
Example: Water treatment plants must add chemicals to purify our drinking water.

44. Water
Treatment
Plant

45. #3 Separating Solids Mixed with Liquids Use a paper filter to drain the liquid and the solid remains in the filter #4 Separating Solids Recycling centers use magnets to separate cans made of aluminum from those made of steel; magnets stick to steel!