1. Lesson 2-3: CLASSIFYING MATTER
Science 9: Unit B – Matter and Chemical Change
Lesson 2-3: CLASSIFYING MATTER

2. The Study of matter and how it changesis
Matter is anything having mass and volume.
Mass- the amount of matter in an object
CHEMISTRY
Mass is measured with a balance, unit is grams
mass is related to weight but isn’t the same thing.
weight is dependent upon gravity.
mass never changes
Volume- anything that takes up space, unit L, cm3, mL

3. IS AIR MATTER? YES, to both, so air is matter Does air have volume?
Have a balloon both empty and inflated, and an electronic scale. Weigh balloon.
YES, to both, so air is matter
Does air have volume?
Does air have mass?

4. PROPERTIES OF MATTER
Composition- what matter is made of. Water is made of hydrogen and oxygen (H2O), tea has caffeine
Properties-what matter is like. For example, water can dissolve many substances and caffeine is a stimulant.
What caffeine is made of…
What caffeine is like…

5. THE BASIC UNIT OF MATTER IS AN ATOM
There are over 118 varieties of atoms
PERIODIC TABLE

6. ELEMENTS contain only one type of atom.
Ex: hydrogen (H) is an element that contains only hydrogen atoms, carbon (C) contains only carbon atoms, oxygen (O) contains only oxygen atoms, etc.
Atoms of elements can combine together to form compounds.
COMPOUNDS are neutral groups of atoms held together by chemical bonds.
Ex: CO2, H2O, H2, O2

7. HOW DO WE CLASSIFY MATTER?
All matter is classified as either a pure substance or a mixture
Alloy rims/ mixture of two metals
Pure gold/Pure substance
pure substance
mixture
24 karat
18 karat
End of introductory material. Return to index

8. CLASSIFYING MATTER
Pure substance-a type of matter where all samples, no matter how big or small, have the same properties…they behave in exactly the same way.
Elements
Compounds
Elements contain one type of atom, thus they CANNOT be broken down into simpler substances by chemical means.
Elements consist of either:
single atoms, such as Carbon (C), or Sodium (Na)
groups of atoms of the same type (molecules), such
as H2, O2, Br2, etc.

9. ELEMENTS
MONATOMIC ELEMENTS
DIATOMIC ELEMENTS
ALLOTROPES
Atomic nitrogen N Molecular nitrogen N Ozone O3
Atomic hydrogen H Molecular hydrogen H Graphite, buckyball
Atomic oxygen O Molecular oxygen O2
Carbon C
ALLOTROPE-different forms of an element in same physical state

10. COMPOUNDS Compounds are substances made up of 2 or more different
elements that are chemically combined. CO2, H2O, HCl, Na2SO4
COMPOUNDS CAN BE BROKEN DOWN INTO SIMPLER SUBSTANCES BY CHEMICAL MEANS ONLY.
COMPOUNDS HAVE DIFFERENT PROPERTIES THAN THE ELEMENTS THAT MAKE THEM UP.
Example-dehydration of sugar: C12H11O22 12C(s) + 11 H2O(g)
Sugar breaks down into carbon and water
Wanna see?

11. ELEMENTS TO COMPOUND Will Form…
Sodium, Na, is a soft, shiny metal that can be cut with a butter knife. When in contact with moisture it will “explode”.
COMBINED WITH…
Chlorine gas, Cl2, which is a green, poisonous gas once used as a chemical weapon in military operations.
Will Form…

12. TABLE SALT! 2 Na(s) + Cl2(g)  2 NaCl
Sodium metal and chlorine gas, under the right conditions, undergo a chemical change and combine to become…..
2 Na(s) + Cl2(g)  2 NaCl
The final compound has properties different from the elements that formed it.

13. REVIEW
We are studying CHEMISTRY, the study of ________and how it ________.
Matter is anything that has___ and takes up ___.
___ are the basic building blocks of matter.
Matter can be classified as either a ___ or a ___.
Substances are either ___ or ___.
Answers:
1. matter, changes 2. mass, space 3. atoms 4. pure substance, mixture 5. elements, compounds

14. ? THUS FAR WE HAVE REVIEWED MATTER AS PURE SUBSTANCES.
NOW LETS DISCOVER MATTER AS MIXTURES
MATTER
PURE SUBSTANCE
ELEMENT
COMPOUND
Carbon (C)
H2O
MIXTURE ?

15. MATTER AS MIXTURES
Mixtures are combinations of 2 or more substances where each substance retains its individual properties.
HOW ARE MIXTURES LIKE COMPOUNDS?
THEY ARE MADE FROM TWO OR MORE SUBSTANCES
HOW ARE MIXTURES DIFFERENT FROM COMPOUNDS?
MIXTURES DO NOT FORM CHEMICAL BONDS.

16. There are two types of mixtures:
Classifying mixtures
There are two types of mixtures:
1) HOMOGENEOUS
2) HETEROGENEOUS

17. is HOMOGENEOUS …a mixture that is the same throughout.
A homogeneous mixture has a
composition and properties that are
identical regardless of the sample is
Ways to identify a homogeneous mixture:
HOMOGENEOUS
one phase
uniformly mixed
won’t settle out
small particles
A SOLUTION is another name for a homogeneous mixture

18. HETEROGENEOUS is … a mixture that is visibly different
throughout. Heterogenous mixtures have
a composition and properties that differ
in any given sample.
not uniformly mixed
more than one phase
will settle out
larger particles
Ways to identify a homogeneous mixture:
HETEROGENEOUS

19. HETEROGENEOUS MIXTURES
There are special types of heterogeneous mixtures:
Suspensions-appear uniform when mixed but settle out.
Chocolate Quik
Muddy water
Pulpy oj
Oil & Vinegar dressing
Colloids-appear uniform but they do not settle out. However, their particles are too large to be classified as a homogeneous solution.
Gelatin
Milk
Smoke
Fog
mayonnaise

20. TYNDALL EFFECT
Colloids are evenly mixed, but their particles are too large to be considered homogeneous mixtures, which are also the same throughout.
Colloids show the Tyndall Effect. The Tyndall effect is the scattering of light as a beam passes through a colloid.
In each picture, the colloid on the left scatters the beam making it visible

21. Heterogeneous Mixture
Mixtures Summary
Heterogeneous Mixture
Homogeneous Mixture
Not evenly mixed
Evenly mixed
Individual components retain their own properties
Properties of combined components are usually different than those of each component
Individual components can be easily seen
Individual components can not be easily seen
Can be easily separated
Not as easily separated
Ex.: salt & pepper mix, rocks, cereal, bag of assorted candy
Ex. salt-water solution, tea, Cool-Aid drink

22. Practice Problems Tossed salad Salt water Kool-aid Muddy water
Determine whether each is a heterogeneous or homogeneous mixture:
Tossed salad
Salt water
Kool-aid
Muddy water
OJ with pulp
6. Tea
7. Banana nut bread
8. Pizza
9. Blood
10. Brass
Answers:
1. He 2. Ho 3. Ho 4. He 5. He 6. Ho 7. He 8. He 9. He 10. Ho

23. Now, lets put it all together and determine how to tell substances (compounds and elements) from mixtures.
Pure Substances
Made of either elements or compounds that are chemically bonded.
Cannot be separated by physical means.
When combined they take on new properties different from the original elements.
Examples:
Glucose: C6H12O6
Table Salt: NaCl
Oxygen Gas: O2
Carbon Dioxide CO2
Mixtures:
Two or more substances mixed together but not chemically combined.
Tea = Crushed Leaf + H2O
Rocks = minerals + sediments + organic matter
Sugar Water = Sugar + H2O
Each component retains its own identity; it does not change into something else.
Can be separated by physical means
Examples:
Sweet tea
Trail mix
Air (O2, N2, CO2, Ar)

24. Elements, Compounds, and Mixtures
Two types of atoms evenly mixed
Two types of atoms chemically combined
One type of atom
Two types of atoms mixed
An element
A solution
A compound
A mixture
Two of the descriptions to the right apply to each bottle below. Determine the appropriate descriptions.
hydrogen
atoms
oxygen atoms
hydrogen
atoms
d & h
b & g
c & e
a & f
1_______
2_______
3_______
4_______
Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 68

25. Classifying Matter Matter Pure Substances Mixtures Tea, kool-aid He, O
Review: How matter is classified
Matter
Pure Substances
Mixtures
Homogeneous
Heterogeneous
Elements
Compounds
Rocky Road ice cream, muddy water
Tea, kool-aid
He, O
H2O, NaCl 25

26. More review
Classify the following substances as: Pure substance, heterogeneous mixture, or homogeneous mixture
Gatorade
Homogenous mixture
Fruit Loops
Heterogeneous mixture
Pure substance
Gasoline
Dirt
Sugar Crystals
Pure Substance
Air
Homogeneous mixture
Granite
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