1. Also know as DIMENSIONAL ANALYSIS
FACTOR LABEL METHOD
Also know as DIMENSIONAL ANALYSIS

2. DO NOW
Pick up Factor Label Notes.
Turn in any missing work.

3. METRIC SYSTEM REMINDERS
If you are going from BIGGER to SMALLER, multiply or move the decimal to the right.
If you are going from SMALLER to BIGGER, divide or move the decimal to the left.
Kilo- Hecto- Deka- Root Deci- Centi- Milli-
BIGGER SMALLER

4. METRIC SYSTEM REMINDERS
25000
25hg = _______________dg
Bigger to smaller
Multiply or move to the right.
250cm = ______________ dam
Smaller to bigger
Divide or move to the left
0.250

5. QUIZ TOMORROW OVER METRICS

6. FACTOR LABEL METHOD
How many seconds are in 30 minutes? How many seconds are in 125 years?

7. FACTOR LABEL METHOD
Many types of problems in chemistry can be solved by the factor-label method, which makes use of conversion factors. A conversion factor shows the relationship between various units with a ratio equal to one. For instance:
1 meter = 100 centimeters OR
1 kg OR g
1000 g kg

8. FACTOR LABEL METHOD
Either factor is numerically equal to one, and therefore, may be multiplied by any quantity without changing its value.
When writing conversion factors, it is important always to label each number with its unit.
It is from the use of factors and unit-labeled numbers that this method gets its name: “Factor Label”.

9. FACTOR LABEL METHOD
Example One: How many kilograms are there in 125 grams of a substance?
From the two conversion factors that can be formed from the equality between grams and kilograms, as shown above, we choose the one that will cause the unit GRAMS to divide or cancel out and leave the unit KILOGRAMS in the answer:

10. FACTOR LABEL METHOD
? kg = 125g x 1 kg = kg
1000g

11. FACTOR LABEL METHOD

12. FACTOR LABEL METHOD
Example Two: Find the number of centimeters in 5 kilometers.
? cm = 5km x 100cm x 1000m = 500,000cm
1 m km

13. TO DO
Metric and Factor-Label Practice handout