Matter
Properties and Composition
http://z.about.com/d/chemistry/1/0/x/c/transitionmetalsolns.jpg
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Barbara A. Gage
Properties
• Physical Property - any property that
can be observed without transforming
the substance into another substance
mass, color, freezing point
• Chemical Property - any property that
cannot be studied without transforming
the substance into a different
substance
iron rusts, paper burns
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Barbara A. Gage
Changes
• Physical Change - change that does not
transform the substance into another
substance
melting, subliming, dissolving
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Barbara A. Gage
Changes
• Chemical Change - change that
transforms the substance into another
substance
burning, oxidation of metal
• http://jchemed.chem.wisc.edu/JCESoft
/CCA/pirelli/pages/cca1NaIHgCl2.html
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Barbara A. Gage
Chemical Change
From Silberberg, Principles of Chemistry, 2007
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Barbara A. Gage
Figure 1.1
The distinction between physical and chemical change.
(Silberberg)
A Physical change
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B Chemical change
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Sample Problem 1.1
(Silberberg)
Distinguishing Between Physical and
Chemical Change
PROBLEM: Decide whether each of the following process is primarily a
physical or a chemical change, and explain briefly:
(a) Frost forms as the temperature drops on a humid winter night.
(b) A cornstalk grows from a seed that is watered and fertilized.
(c) Dynamite explodes to form a mixture of gases.
(d) Perspiration evaporates when you relax after jogging.
(e) A silver fork tarnishes slowly in air.
PLAN:
“Does the substance change composition or just change
form?”
SOLUTION:
(a) physical change
(b) chemical change
(d) physical change
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(c) chemical change
(e) chemical change
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Barbara A. Gage
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Types of Matter
• Element - the simplest type of
substance with unique physical and
chemical properties. It cannot be
broken down into any simpler substances
by physical or chemical means.
• Compound - a substance composed of
two or more elements which are
chemically combined.
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Figure 2.19
The distinction between mixtures and compounds.
Silberberg
S
Fe
Physically mixed therefore can be
separated by physical means; in
this case by a magnet.
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Allowed to react chemically
therefore cannot be separated by
physical means.
Barbara A. Gage
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Types of Matter
• Atom – smallest unit of an element with
all the characteristics of the element
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Types of Matter
• Molecule - a structure that consists of
two or more atoms that are chemically
bound together and thus behaves as an
independent unit.
Figure 2.1
Silberberg
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Barbara A. Gage
The boxes here contain
submicroscopic views of
particles. Indicate
which box(es) contain
the stated item(s) and
why.
a.only elements
b.only one compound
c.mixture of compounds
d.molecules
a.
b.
c.
d.
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B, C, E
A (plus an element), D
F
All but E
Barbara A. Gage
Element Names and Symbols
• Number of elements – 117 (#117 has not
been identified but 118 has)
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Element Names and Symbols
• Each element has a name and 1, 2 or 3
letter abbreviation called a symbol. The
first letter in a symbol MUST be capital
and the other(s) lowercase.
•
•
•
•
hydrogen
carbon
sodium
lead
H
C
Na
Pb
helium
He
cobalt
Co
potassium K
mercury Hg
Image from WebElements
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Element Names and Symbols
• You must know the names and symbols
of the first 38 elements on the periodic
table along with Ag, Cd, Sn, I, Ba, Hg,
Pb.
• Spelling counts!
• Make flashcards to help
learn them.
www.chem.purdue.edu/gchelp/liquids/bromine.gif
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Barbara A. Gage
Chemical Formulas
• Some elements appear in nature bonded
to each other. These are referred to
as diatomic or polyatomic molecules.
H2, O2, N2, F2, Cl2, Br2, I2 (must know)
C60, S8, P4
• The 2 in O2 is termed a subscript and
refers to the element immediately in
front of it.
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Chemical Formulas
• CO2 contains 1 atom of carbon and two
atoms of oxygen all chemically linked.
• H2SO4 contains 2 hydrogen, 1 sulfur,
and 4 oxygen atoms.
• (NH4)2C2O4 - A subscript outside
parentheses applies to everything within
the parentheses; 2 N, 8 H, 2 C, 4 O
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