Download II. Classification of Matter

Ch. 1 – Matter and
Its Properties
Scientific Method
 Steps
 Ask
a __________________________
 Observe and collect data
 Formulate a hypothesis (a testable if-then
statement). The hypothesis serves as a
basis for making predictions and for
carrying out further experiments.
 Test your ______________________ –
Requires experimentation that provides
data to support or refute your hypothesis.
Terms to Know
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Law vs. theory
Scientific (natural) _____________: a general
statement based on the observed behavior of
matter to which no exceptions are known.
__________________: a broad generalization
that explains a body of facts or phenomena.
Quantitative vs. qualitative data
Quantitative: numerical
(__________________________________)
Qualitative: descriptive
(___________________________________)
Properties & Changes in
Matter
Extensive vs. Intensive
Physical vs. Chemical
A. Extensive vs. Intensive
 Extensive Property
 depends on the amount of matter
present
 Intensive Property
 depends on the identity of substance,
not the amount
A. Extensive vs. Intensive
 Examples:
 boiling point
intensive
 volume
extensive
 mass
extensive
 density
intensive
 conductivity
intensive
B. Physical vs. Chemical
 Physical Property
 can be observed without changing the
identity of the substance
 Chemical Property
 describes the ability of a substance to
undergo changes in identity
B. Physical vs. Chemical
 Examples:
 melting point
physical
 flammable
chemical
 density
physical
 magnetic
physical
 tarnishes in air
chemical
B. Physical vs. Chemical
 Physical Change
 changes the form of a substance
without changing its identity
 properties remain the same
B. Physical vs. Chemical
 Chemical Change
 changes the identity of a substance
 products have different properties
B. Physical vs. Chemical
 Signs of a Chemical Change
 change in color or odor
 formation of a gas
 formation of a precipitate (solid)
 change in light or heat
B. Physical vs. Chemical
 Examples:
 rusting iron
chemical
 dissolving in water
physical
 burning a log
chemical
 melting ice
physical
 grinding spices
physical
Ch. 1 - Matter
Classification of Matter
(p.15-17, 397-398)
 Matter Flowchart
 Pure Substances
 Mixtures
A. Matter Flowchart
MATTER
yes
Can it be physically
separated?
no
PURE SUBSTANCE
MIXTURE
yes
Is the composition
uniform?
Homogeneous
Mixture
(solution)
no
Heterogeneous
Mixture
Colloids
yes
Can it be chemically
decomposed?
Compound
Suspensions
no
Element
A. Matter Flowchart
 Examples:
 graphite
element
 pepper
hetero. mixture
 sugar (sucrose)
compound
 paint
hetero. mixture
 soda
solution
B. Pure Substances
 Element
 composed of identical atoms
 EX: copper wire, aluminum foil
B. Pure Substances
 Compound
 composed of 2 or more
elements in a fixed ratio
 properties differ from those
of individual elements
 EX: table salt (NaCl)
B. Pure Substances
 Law of Definite Composition
 A given compound always contains
the same, fixed ratio of elements.
 Law of Multiple Proportions
 Elements can combine in different
ratios to form different compounds.
B. Pure Substances
 For example…
Two different compounds,
each has a definite composition.
C. Mixtures
 Variable combination of 2 or more pure
substances.
Heterogeneous
Homogeneous
C. Mixtures
 Solution
 homogeneous
 very small particles
 no Tyndall effect
 particles don’t settle
 EX: rubbing alcohol
Tyndall Effect
C. Mixtures
 Colloid
 heterogeneous
 medium-sized particles
 Tyndall effect
 particles don’t settle
 EX: milk
C. Mixtures
 Suspension
 heterogeneous
 large particles
 Tyndall effect
 particles settle
 EX: fresh-squeezed
lemonade
C. Mixtures
 Examples:
 mayonnaise
colloid
 muddy water
suspension
 fog
colloid
 saltwater
solution
 Italian salad
dressing
suspension