Chemistry 2 Chapter 2

1
Chemistry 2Chapter 2

• Matter and Change

2
Properties of Matter 2.1
What would you like to know about the extensive
and intensive properties of bamboo? What
characteristic makes bamboo useful for cooking
tools? FYI Characters on the chop sticks
translate as good fortune, prosperity, longevity,
and good health.
3
Describing Matter 2.1

• Matter anything that takes up space
• Mass amount of matter the object contains
• Volume Space occupied by object
• Extensive Property
• Depends on the amount of matter in a sample
• Volume and Mass
• Intensive
• Depends on the type of matter in a sample, not
  the amount

4
Identify Substance 2.1

• Substance matter that has a uniform and
  definite composition
• Every sample of same substance is identical
• Physical Property quality or condition of a
  substance that can be OBSERVED or MEASURED
  without changing substance
• Ex hardness, color, conductivity, malleability,
  melting point, boiling point
• Help ID substance

5
Copper vs. GoldPhysical Property Differences

• Copper
• Scratch surface of pure gold (harder than gold)
• Better conductor of heat/electricity
• Malleable
• Reddish-yellow
• MP 1084 Celsius
• BP 2562 Celsius
• Gold
• More malleable
• Yellow
• MP 1054 Celsius
• BP 2856 Celsius

6
States of Matter 2.1

• Visualize the structure of solids, liquids, and
  gases at the microscopic level
• Solids definite shape and volume
• Particles packed tightly together
• Liquids indefinite shape, flows, but fixed
  volume
• Tend to expand when heated
• Incompressible (mostly)
• Gases - takes shape and volume of container
• Gas exists in gaseous state at room temp.
• Vapor gaseous state of substance that genarlly
  solid/liquid at room temp.

7
(No Transcript)
8
Physical Changes 2.1

• Composition of martial does NOT CHANGE, physical
  properties may change
• Boil, freeze, melt, condense, break, split,
  grind, cut, crush
• Reversible One state of matter to another
• Irreversible cutting, cracking, etc
• Look at Figure 2.4
• What can you infer about the temperature of hand
  holding gallium?
• Is the melting of gallium a reversible or
  irreversible?
• What is the physical state of gallium at room
  temperature?

9
Technology and Society

• 1/3 of spiders spin webs, all produce silk
• Silk for wrapping prey, wrapping eggs,
  draglines, trap prey
• Silk proteins strong, tough, an elastic
• FYI OH REALLY!!!!
• A cable of golden org dragline silk that is
  slightly thicker than a garden hose would be
  strong enough to support two jet planes full of
  passengers and cargo without braking!!!!!!!!!
• History of silk
• Used to catch fish/birds
• Use as bandages

10
Technology and Society

• Spider web 1/10 diameter of hair
• Golden orb spider silk
• More elastic than nylon
• Tougher than rubber
• Stronger than steel
• Cant harvest b/c spider will fight to defend
  territory

11
Mixtures 2.2
What is the result of panning? What property is
used to separate the mixture?
12
Classifying Mixtures 2.2

• Mixture physical blend of 2 or more components
• most matter
• Ex chicken noodle soup, air
• Heterogeneous Mixture
• composition is not uniform
• More than 2 phases
• Homogeneous Mixture composition is uniform
  throughout
• solution many are liquids
• Phase describe any part of a sample with
  uniform composition
• 1 phase
• Conceptual Problem 2.1 (9 and 10)

13
Separating Mixtures 2.2

• Decant pour off (like olive oil and vinegar)
• Cool one part would turn solid
• Filtration
• Colander (strainer)
• Separates solid from liquid
• Distillation
• Liquid boiled to produce a vapor that is
  condensed into a liquid
• Flask is heated, water vapor forms, rises in
  flask, and passes into a glass tube in the
  condenser, tube surrounded by cold water, turns
  vapor into water

14
http//www.youtube.com/watch?v3JlIPnyrZMw
15
Elements and Compounds 2.3
16
Distinguishing Elements and Compound 2.3

• Element simplest form of matter with unique set
  of properties
• Can not be broken down
• Compound substance that contains 2 or more
  elements chemically combined in a fixed
  proportion
• Can be broken down

17
Breaking Down Compounds 2.3

• Chemical Change change that produces matter
  with a different composition than the original
  matter
• Can not use same method to SEPERATE mixtures as
  you can compounds
• There are many different ways to break down
  compounds (heat, electricity),

18
Properties of Compounds

• Elements change physical/chemical properties when
  mixed with other elements
• Chlorine Use to kill harmful organisms in pools
• Sodium Stored under oil to keep it from reacting
  with oxygen sodium vapor produces the light in
  some street lamps
• Sodium chloride (table salt) season and preserve
  food

19
Substance vs. Mixture?????

• Hard to tell substance or mixture based on
  appearance
• Whole, 2 1 ½ skim milk, light or heavy cream,
  different blends of gasoline can tell mixtures
• composition fixed material SUBSTANCE
• Composition varies material MIXTURE
• A MIXTURE is a combination of two or more
  substances that are not chemically united and do
  not exist in fixed proportions to each other
• A physical process (like evaporation or heating)
  cannot be used to breakdown a compound

20
(No Transcript)
21
(No Transcript)
22
Symbols and Formulas 2.3

• Symbols represent elements
• C Carbon
• Formulas represent compounds
• NaCl Sodium Chloride or Table Salt
• Jons Jacob Berzelius (1779 1848)
• Developed symbols for elements
• Based on Latin names of elements
• Chemical Symbols 1 or 2 letters
• 1st letter capitalized, 2nd letter lowercase
• Subscript indicate relative proportions of the
  elements in a compound
• Compound fixed formula is always same

23
Chemical Reactions 2.4
What evidence do you see in the photo that a
chemical reaction has occurred?
24
Chemical Changes 2.4

• Chemical change words burn, rot, rust,
  decompose, ferment, explode, and corrode
• Chemical Property Ability of a substance to
  undergo a specific chemical change
• Observed only when substance undergoes chemical
  change/ chemical reaction (matter always changes)
• Physical change composition doesnt change
• 4Fe 3O2 ? 2Fe2O3
• Iron Oxygen ?Iron Oxide
• Reactant ? Product

25
Recognize Chemical Changes 2.4

• 4 clues
• Transfer of energy (methane combines with oxygen
  energy, heat, to cook food in grills)
• Change in color (food browns as it cooks)
• Production of a gas (bubbles during a reaction)
• Formation of precipitate
• Solid that forms and settles out of a liquid
  (soap scum)
• EVEN IF you observe one of the 4 clues, does not
  give certainty of chemical change
• Ex boiling water is a physical change

26
Conservation of Mass 2.4

• Law of Conservation of Mass - any physical or
  chemical change mass if neither created nor
  destroyed
• Easier to observe in a closed container
• Matter can be released into the air or
  surroundings