FACTOR LABEL METHOD

FACTOR LABEL METHOD 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 ConvertBetween 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 needto change (convert) from one unit toanother.

What is dimensional analysis? 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 termsthat 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

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 73 inches ___________cm 1779 sec ___________minutes

This is a DIFFERENT FORMULA LOOK!! 3.5 miles = ________mStep 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 mNow set it up …..remember Feet will be our linking unit because

it’s linking our starting to desired

3.5 miles = ________m 3.5 miles X _______feet X ________meters = meters mile feet Now fill it in with the conversion factors 3.5 miles X 5280feet X _0.3048meters = 5632.7 meters 1 mile 1 ft

1 mile= 5280ft AND 1 ft = 0.3048 m

3 m= ______in

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?

7 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

. How many basketballs can be carried by 5 buses?

·  1 bus = 12 cars ·  3 cars = 1 truck ·  1000 basketballs = 1 truck