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Lecture 2:
Measurements and Scientific
Notation
• Goals:
Be familiar with the base units and
abbreviations for the metric system, write numbers
using scientific notation and be able to use prefixes to
change base units to larger or smaller units
• Outline
(Timberlake Chapter 1.11.2, 1.5)
:
±
Units of Measurement (1.1)
±
Scientific Notation (1.2)
±
Prefixes and Equalities (1.5)
• Problems for Extra Practice:
1.1, 1.3, 1.5, 1.7,
1.9, 1.35, 1.37, 1.39, 1.41
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View Full Document Units Listed on Labels
Stating a Measurement
In every measurement, a
number
is
followed
by a
unit
.
Observe the following examples of measurements:
Number and Unit
35
m
0.25
L
225
lb
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View Full Document The SI System
•
Scientists recognized that a standard system of
units was needed if measurements were to be
useful
–
Two major systems
•
English
•
Metric
•
In 1960, an international agreement set up a
system of units called the International System
(SI)
–
Based on the metric system and units derived from
the metric system
–
related decimal systems based on 10
Measurements  Length
•
Length
– Uses the unit
meter (m)
in
both the SI and metric
systems
1 meter = 39.4 inches
– Measured with a meter stick
– centimeter (cm) is a smaller
unit of length
1 inch = 2.54 cm
– A dime is 1 mm thick.
– A quarter is 2.5 cm in
diameter.
– The average height of an adult
male is 1.8 m.
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View Full Document Measurements  Volume
•
Volume
– amount of space a
substance occupies
– uses the unit
liter (L)
in the metric
system
1 L = 1.06 qt
– uses the unit
cubic meter (m
3
)
in
the SI system
– is measured using a graduated
cylinder
– milliliter (mL) more convenient for
measuring smaller quantities
– A 12 oz can of soda has a volume of
about 360 mL.
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This note was uploaded on 01/18/2012 for the course CHEM 120A taught by Professor Leahmiller during the Fall '11 term at University of Washington.
 Fall '11
 LeahMiller

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