Transcript Matter Properties and Composition http://z.about.com/d/chemistry/1/0/x/c/transitionmetalsolns.jpg CHM 1010 PGCC Barbara A. Gage Properties • Physical Property - any property that can be observed without transforming the substance into another.

Matter
Properties and Composition
http://z.about.com/d/chemistry/1/0/x/c/transitionmetalsolns.jpg
CHM 1010
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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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Chemical Change
From Silberberg, Principles of Chemistry, 2007
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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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CHM 1010
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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.
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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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The boxes here contain
submicroscopic views of
particles. Indicate
which box(es) contain
the stated item(s) and
why.
a.only elements
b.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
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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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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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