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Matter and Change
I. Chemistry As a Physical Science
Chemistry
Chemistry the study of the composition, structure,
and properties of matter and the changes that matter undergoes
Chemical any substance that has a definite
composition or is used or produced in a chemical process
6 Branches of Chemistry
organic chemistry- the study of most carbon-containing chemicals
inorganic chemistry- the study of nonorganic substances
6 Branches of Chemistry
biochemistry- the study of substances and processes occurring in living things
analytical chemistry- the identification of the components and composition of materials
6 Branches of Chemistry
physical chemistry- the study of the properties and changes of matter and their relation to energy
6 Branches of Chemistry
Theoretical chemistry- the use of mathematics and computers to understand the principles behind observed chemical behavior and to design and predict new compounds
Chemistry vs. Technology
Basic research- the pursuit of chemical knowledge for its own sake
Applied research- research that is directed toward a practical goal or application
Chemistry vs. Technology
Basic research can lead directly to an application, but an application can’t exist before research is done to explain how it works.
→ need a problem first
Chemistry vs. Technology
Chemistry differs from technology… i.e. AspirinDetermining the structure of aspirin
is chemistryUsing aspirin to relieve pain and
reduce fever is technology
Ch. 1 – Matter and Change
II. Matter and Its Properties
Matter Flowchart
MATTER
Can it be physically separated?
Homogeneous Mixture
(solution)
Heterogeneous Mixture Compound Element
MIXTURE PURE SUBSTANCE
yes no
Can it be chemically decomposed?
noyesIs the composition uniform?
noyes
Colloids Suspensions
Pure Substances
Every sample has exactly the same characteristic properties
Every sample has exactly the same composition
Pure Substances
Element composed of identical atoms EX: copper wire, aluminum foil
Pure Substances
Compound
composed of 2 or more elements in a fixed ratio
properties differ from those of individual elements
EX: table salt (NaCl)
Pure Substances
For example…
Two different compounds, each has a definite composition.
Matter Flowchart
Examples:
graphite
pepper
sugar (sucrose)
paint
soda
element
hetero. mixture
compound
hetero. mixture
solution
Mixtures
Variable combination of 2 or more pure substances.
Heterogeneous Homogeneous
Mixtures
Solution homogeneous very small particles particles don’t settle EX: rubbing alcohol
Mixtures
Suspension heterogeneous large particles particles settle EX: fresh-squeezed
lemonade
Mixtures
Examples:
mayonnaise
muddy water
fog
saltwater
Italian salad dressing
colloid
suspension
colloid
solution
suspension
C. Johannesson
Extensive vs. Intensive
Extensive Property
depends on the amount of matter present
Intensive Property
depends on the identity of substance, not the amount
C. Johannesson
Extensive vs. Intensive
Examples:
boiling point
volume
mass
density
conductivity
intensive
extensive
extensive
intensive
intensive
C. Johannesson
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
C. Johannesson
Physical vs. Chemical
Examples:
melting point
flammable
density
magnetic
tarnishes in air
physical
chemical
physical
physical
chemical
C. Johannesson
Physical vs. Chemical
Physical Change
changes the form of a substance without changing its identity
properties remain the same
Chemical Change
changes the identity of a substance
products have different properties
C. Johannesson
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
C. Johannesson
Physical vs. Chemical
Examples:
rusting iron
dissolving in water
burning a log
melting ice
grinding spices
chemical
physical
chemical
physical
physical
C. Johannesson
Four States of Matter
Solids particles vibrate but can’t
move around fixed shape fixed volume
C. Johannesson
Four States of Matter
Liquids particles can move
around but are still close together
variable shape fixed volume
C. Johannesson
Four States of Matter
Gases particles can separate and
move throughout container variable shape variable volume
C. Johannesson
Four States of Matter
Plasma particles collide with enough energy
to break into charged particles (+/-) gas-like, variable
shape & volume stars, fluorescent
light bulbs, CRTs
Ch. 1 – Matter and Change
III. Elements
33
Modern Periodic TablePeriod- horizontzal row
34
Group or Family - Vertical column
Modern Periodic Table
Metals, Nonmetals, Metalloids
Metals
solids at room temperature, have a grayish color and shiny surface and conduct electricity
largest region excellent conductor of heat lustrous ductile malleable
Nonmetals
second largest region on table vary in properties a bit poor conductor gases or brittle solids at room temp.
Metalloids
an element having properties of metals as well as nonmetals
some have conductive properties some have luster some brittle solid at room temp. semiconductors