1. Using Conversion Factors in Unit Analysis (Dimensional Analysis) Problem-solving method that uses the fact that any number or expression can be multiplied by one without changing its value
1 dozen eggs or
12 eggs

2. Doing Problems Read problem completely
Determine the measured qty. in the problem and the units
Determine units being requested
Determine conversion factor that will allow you to change to the new unit

3. We will look at converting: 1. English units 2
We will look at converting: English units English units to Metric Units 3. Metric units

4. Converting from English to English,
75 cookies is equivalent to how many dozen cookies?
? dozen = 75 cookies X
1 dozen
= 6.25 dozen
12 cookies

5. Series of unit factors – 2 possible formats

6. Converting English Units

7. Converting English Units to Metric Units
How many centimeters are in 6.00 inches?
? cm = 6.00 inches X
2.54 cm
= cm
1 inch
= 15.2 cm

8. Conversion of Metric Units

9. Remember the order of the units!
kilo
hecto
deca
Base Unit
deci
centi
milli
micro k h da
gram (g) d c m μ
1000
100 10
liter (L)
0.1
0.01
0.001
103
102
101
meter (m)
10-1
10-2
10-3
10-4
10-5
10-6

10. Steps:
Given quantity w/its unit
Set up conversion factor
Place given unit as the denominator of the conversion factor
Place desired unit as the numerator
Place a “1” in front of the large unit
Place a 10 in front of the smaller unit
Repeat b-d until reaching the final answer
Cancel Units – only the desired unit should be left
Solve the problem
An aspirin tablet contains 325 mg of active ingredient. How much is this in cg?
325 mg
1 cg
= = 32.5 cg 1
10 mg 10
= 32.5cg of active ingredient

11. Convert 50.0 mL to liters?
50.0mL 1 cL dL L = 50
mL cL 10 dL 1000
= L