Download Prefix and Sig Fig Notes

MEASUREMENTS
Prefix
Notes
SIGNIFICANT FIGURES
Rules for Counting Significant Figures
1. Nonzero integers always count as significant figures.
1457 has 4 significant figures
23.3 has 3 significant figures
METRIC PREFIXES
Increase or decrease basic unit by 10
Form new units larger or smaller than the
basic units
Indicate a numerical value
prefix
=
value
1 kilometer
=
1000 meters
1 kilogram
=
1000 grams
3
PREFIXES THAT INCREASE A UNIT
Prefix
Symbol
Value
giga-
G
1 000 000 000
megakilo-
M
k
1 000 000
1 000
4
PREFIXES THAT DECREASE A UNIT
Prefix
Symbol
decicentimillimicronano-
d
c
m
u
n
Value
0.1
0.01
0.001
0.000 001
0.000 000 0001
5
LEARNING CHECK
Match 1) length
volume
2) mass
3)
_2 A.
A bag of tomatoes is 4.6 kg.
__
1 B.
A person is 2.0 m tall.
__
2 C.
A medication contains 0.50 g Aspirin.
__
3 D.
A bottle contains 1.5 L of water.
6
LEARNING CHECK
Indicate the prefix to use for
1. A mass that is 1000 times greater than 1
gram
1) kilo
2) milli
3) mega
2. A length that is 1/100 of 1 meter?
1) deci
2) centi
3) milli
3. A unit of time that is 1/1000 of a second.
1) nanosecond
2) microsecond
3)millisecond
7
MEASUREMENTS
Sig Figs
Notes
SIGNIFICANT FIGURES
Rules for Counting Significant Figures
2. Zeros
a. Leading zeros - never count
0.0025
2 significant figures
b. Captive zeros (zero sandwich) - always count
1.008
4 significant figures
c. Trailing zeros - count only if the number is written
with a decimal point
100
1 significant figure
100.
3 significant figures
120.0 4 significant figures
SIGNIFICANT FIGURES
Rules for Counting Significant Figures
3. Exact numbers - unlimited significant figures
• Not obtained by measurement
 Determined by counting:
3 apples
 Determined by definition:
1 in. = 2.54 cm
SIGNIFICANT FIGURES
Rules for Addition and Subtraction
• The number of significant figures in the result is the
same as in the measurement with the smallest number
of decimal places.
SIGNIFICANT FIGURES
Rules for Multiplication and Division
• The number of significant figures in the result is the
same as in the measurement with the smallest number
of significant figures.