Transcript FACTOR LABEL METHOD

FACTOR LABEL
METHOD
FACTOR LABEL METHOD
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In math you use numbers, in chemistry we use
quantities.
A quantity is described by a number and a
unit.
100 is a number : 100 Kg is a quantity
Sometimes You Have to Convert
Between Different Units
How many seconds are in a day?
 How many inches are in a centimeter?
 If you are going 50 miles per hour,how
many meters per second are you traveling?
 To answer these questions you need
to change (convert) from one unit to
another.
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What is dimensional analysis?
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The converting from one unit system to
another.
If this is all that it is, why make such a fuss
about it? Very simple. Wrong units lead to
wrong answers. Scientists have thus evolved
an entire system of unit conversion.
How does it work?
It will involve some easy math (Multiplication & Division)
 To perform any conversion, you need a conversion factor.
 Conversion factors are made from any two terms
that describe the same or equivalent “amounts”
of what we are interested in.
 For example, we know that:
 1 dozen = 12
 12 inches= 1 foot
 1 mile= 5280 ft
 1 inch = 2.54 centimeters
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Look at the formula above you will use this solve the problem
60 inches=__________ ft
Step one what’s your Starting unit?
Inches
What’s your Desired unit?
Feet
What conversion factor are you going to use to convert inches
to feet?
1 foot= 12 inches
Now plug it in!!
60 inches X 1 foot =
5ft
12 inches
Now Use the formula and Solve these
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73 inches ___________cm
1779 sec ___________minutes
This is a DIFFERENT FORMULA LOOK!!
 3.5 miles = ________m
Step 1 what’s the starting unit?
Correct==miles
What’s the Desired?
feet
What are the conversion factors you will use? Look at your
conversion sheet? How can we get from miles to Meters?
1 mile= 5280ft AND 1 ft = 0.3048 m
Now set it up …..remember Feet will be our linking unit because
it’s linking our starting to desired
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1 mile= 5280ft AND 1 ft = 0.3048 m
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3.5 miles = ________m
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3.5 miles X _______feet X ________meters =
mile
feet
Now fill it in with the conversion factors
3.5 miles X 5280feet X _0.3048meters = 5632.7
1 mile
1 ft
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meters
meters
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m= ______in
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6 gal= _____ fl oz
(1 gal = 4qts) (1 qt = 32 fl oz)
What is Qts going to be?
Correct Linking !! Now set it up like the top
formula?
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hrs=_______seconds
our conversion factors are going to be
Hours to min then minutes to seconds
1 hr= 60 min AND 1 min =60 seconds
Set it up
PRACTICE
How many grams in 150 pounds given the
conversion factors
1 pound = 0.454 kg and 1 kg = 1000 grams
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. How many basketballs can be
carried by 5 buses?
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· 1 bus = 12 cars
· 3 cars = 1 truck
· 1000 basketballs = 1 truck