Download Chapter 2: Measurements and Calculations

SI Base Units
Length (l)
Meter (m)
Mass (m)
Kilogram (kg)
Time (t)
Second (s)
Temperature (T)
Kelvin (K) and Celsius (°C)
Amount of Substance (n)
Mole (mol)
Electric Current (I)
Ampere (A)
Luminous Intensity (Iv)
Candela (cd)
Prefixes Used with SI Units
Prefix
kilo
hecto
deca
Symbol
k
h
da
deci
centi
milli
micro
nano
pico
d
c
m

n
p
Exponential Factor
103
102
101
100
10-1
10-2
10-3
10-6
10-9
10-12
Example
kilogram(km)
hectogram (hg)
decagram (dag)
gram (g)
decigram (dg)
centigram (cg)
milligram (mg)
microgram (g)
nanogram (ng)
picogram (pg)
Conversions
Kilo
100
To convert to a smaller unit,
move decimal point to the right
or multiply.
Hecto
100
Deka
10
Basic
Unit
To convert to a bigger unit,
move decimal point to the left
or divide.
Deci
10
Centi
100
Milli
1000
Percent Error = | Experimental Value – Accepted Value | x 100
Accepted Value
Sig Fig Rules
1. Non-Zero Rule: All digits 1-9 are significant.
2. Straddle Rule: Zeros between two significant figures are significant.
3. Righty-Righty Rule: Zeros to the right of a decimal point AND anywhere to the right of
a significant figure are significant.
4. Bar Rule: Any zeros that have a bar placed over them are significant. (Only use this for
zeros that are not already significant: Rules 2 & 3.)
5. Counting Rule: Any time the measurement is determined by simply counting the number
of objects, the value has an infinite number of significant figures.
Rules for Significant Figures in Mathematical Operations
Addition and Subtraction: use the least number of places after the decimal between all the
numbers you are adding or subtracting.
Multiplication and Division: use the least number of sig figs between the numbers you are
measuring.
Steps for Writing Numbers in Scientific Notation
1. Write down all the sig. figs.
2. Put the decimal point between the first and second digit.
3. Write “x 10”
4. Count how many places the decimal point has moved from its original location. This will
be the exponent...either + or −.
5. If the original # was greater than 1, the exponent is +, and if the original # was less than 1,
the exponent is - ....(In other words, large numbers have + exponents, and small numbers
have - exponents.
PERFORMING CALCULATIONS IN SCIENTIFIC NOTATION
Addition and Subtraction
1. IF the exponents are the same, we simply add the numbers in front and bring the exponent
down unchanged.
2. The same holds true for subtraction in scientific notation.
3. If the exponents are NOT the same, we must move a decimal to make them the same.
4. Move the decimal on the smaller number!
Multiplying and Dividing
1. Multiply the front factors first.
2. Then add the exponents.
3. Make sure that only one number is in front of the decimal at the end of the problem.
4. Divide the front factors first.
5. Then subtract the exponents.