1. Matter and Changes in Matter
Dr. Childs
Fall, 2005
Science Laboratory

2. Matter

3. Matter Matter is everything that we see and
many of the things we don’t see (as air). By definition matter has mass and occupies space.
Matter is classified into two major categories:
- Pure substances
- Mixtures
Brass
(mixture of
copper & zinc)
Pure silver

4. Matter
Matter can be changed. These changes may involve physical changes in which the composition of the matter is not changed or chemical changes in which the composition is changed.
Candle burning
Ice melting

5. Pure Substances Pure substances:
- contain the same type of particles throughout.
- have a definite composition.
- may be either elements or compounds -
sodium chloride
NaCl
sodium Na
chlorine Cl

6. Types of Matter

7. Elements & Compounds

8. Elements & Compounds
An element is a pure substance that cannot be broken into anther substance (by ordinary chemical means). Composed of only a single type of atom.
A compound is a pure substance composed by two or more elements
How about some examples?

9. Elements
Many things are made of elements. For example, aluminum is used for foil and for building cars and trailers.
Note: If its on the periodic table its an element!

10. Elements
Sulfur
Gold
Lead
Oxygen
Hydrogen fuel
Sodium lamp

11. Elements magnesium wheels silicon sealant chromium wheels
lithium grease
titanium clubs
carbon fiber

12. Compounds
Compounds are formed when two or more atoms of two or more elements combine chemically (bonding!).
- fixed ratio of elements with a definite formula
- separation into elements requires chemical procedures
Water H2O
Note: Compounds are NOT on the periodic table.

13. Compounds table sugar C6H12O6 table salt NaCl Carbon dioxide
Nitrous oxide
N2O
Sodium hydroxide
NaOH
rust
Fe2O3
Epsom salts
MgSO4

14. Mixtures

15. Mixtures Mixtures are materials made up of two or more
pure substances.
Mixtures can be separated by physical means based on
physical properties:
evaporation filtration
floating magnets
Mixtures may be either
homogeneous (solutions)
heterogeneous

16. Mixtures

17. Mixtures
Homogeneous mixture of metal are “alloys”. Alloys include brass, steel, and white gold.
Homogeneous mixtures in which one substance is dissolved in another is a “solution”. Solutions include coffee, IV fluids, and fog.

18. Homogeneous Mixtures Examples: Sea water water and salt
Coffee coffee, sugar, cream
Blood red cells, white cells, plasma
Air nitrogen, oxygen, CO2
Brass copper, zinc
White gold gold, silver, platinum

19. Homogeneous Mixtures Corn flakes Brass Coffee jello Salt water colored
Blood

20. Heterogeneous Mixtures
Examples:
raisin bran cereal with raisins
chocolate chip cookie
tossed salad lettuce, tomatoes, carrots
pizza pizza with meat, cheese
granite feldspar, mica
Italian dressing oil, water, spice

21. Heterogeneous Mixtures
Italian dressing
Raisin Bran
Tossed salad
Chocolate Chip
cookie
Granite
Marble
Muddy water

22. Separating Mixtures filtration evaporation salt ponds evaporation
distillation

23. Separating Mixtures
chromatography
electrophoresis
centrifugation

24. Physical and Chemical
Changes

25. Physical & Chemical Properties
Be sure to know the difference between:
- Physical properties &
chemical properties
- Physical changes &
chemical changes

26. Physical Properties
Physical properties can be observed without a chemical reaction.
Examples:
color: water is clear, table salt is white
density: aluminum has a density of 2.7 g/cm3
state: oxygen is a gas at room temperature
magnetism: iron is attracted to magnet
texture: gold is shiny

27. Physical Properties What are some physical properties of: sulfur?
lemonade?
dish soap?

28. Physical Changes
In a physical change substances are not altered chemically, including:
state changes
solid  liquid
liquid  gas
mixing or separating
adding sugar to coffee
evaporating sea water for salt
tearing paper

29. Physical Changes State Changes liquid  solid “freezing” water to ice
liquid  gas “evaporation” water to steam
gasoline to vapor
solid  gas “sublimation” dry ice to CO2
sublimation
freezing
evaporation

30. Physical Changes State Changes solid  liquid “melting” ice to water
ice cream melting
gas  liquid “condensation” ice to water
condensation
melting

31. Physical Changes
Physical changes may involve changing shape but not composition;
Breaking glass
Sawing wood
Planing wood

32. Chemical Properties Chemical properties:
The properties of an element or compound in a chemical reaction
Examples:
gasoline is flammable
water can be separated by electrolysis
neon is inert

33. Chemical changes Chemical reactions: - yield new substances
- usually cannot be easily reversed
- may either require or release energy (light, heat, etc.)
Sugars in wood may be split by burning. Combustion yields new substances: CO2 and water and heat and light energy.

34. Chemical Changes Candle burning Fireworks Toasting bread Combustion
Digesting food

35. Chemical Changes bread rising photosynthesis food cooking batteries
rusting

36. The End