1. Do Now Find the number of sig figs in the following numbers 1) 2804 m
2)   2.84 km            
3)   m            
4)   m        
5)   4.6 x 105 m   
Round the following numbers as indicated: 
To four figures:
1)  2) 3) 4)
5)  

2. Units of Measurement

3. What is a Unit Conversion?
A unit conversion is a changing of one unit to another.
Unit Examples:
meters
grams
inches
feet
pounds
seconds
Any time you write down a number in Chemistry, you should have a unit written after it!!!

4. What is a Metric Unit?
Metric units are the universally accepted units around the world (except for the US). They are the easiest to convert.
Metric Unit Examples:
meters
liters
Grams
Base Units – all other metric units are based off of these (km, cm, ml, kg)

5. How many jumps does it take?
Ladder Method 1 2 3
KILO 1000 Units
HECTO 100 Units
DEKA 10 Units
DECI 0.1 Unit
Meters Liters Grams
CENTI 0.01 Unit
MILLI Unit
How do you use the “ladder” method?
1st – Determine your starting point.
2nd – Count the “jumps” to your ending point.
3rd – Move the decimal the same number of jumps in the same direction.
4 km = _________ m
Starting Point
Ending Point
How many jumps does it take? 4. 1
__. 2
__. 3
__.
= 4000 m

6. Conversion Practice Try these conversions using the ladder method.
1000 mg = _______ g 1 L = _______ mL 160 cm = _______ mm
14 km = _______ m 109 g = _______ kg 250 m = _______ km
Compare using <, >, or =.
56 cm m 7 g mg

7. Metric Conversion Challenge
Write the correct abbreviation for each metric unit.
1) Kilogram _____ 4) Milliliter _____ 7) Kilometer _____
2) Meter _____ 5) Millimeter _____ 8) Centimeter _____
3) Gram _____ 6) Liter _____ 9) Milligram _____
Try these conversions, using the ladder method.
10) 2000 mg = _______ g 15) 5 L = _______ mL 20) 16 cm = _______ mm
11) 104 km = _______ m 16) 198 g = _______ kg 21) 2500 m = _______ km
12) 480 cm = _____ m 17) 75 mL = _____ L 22) 65 g = _____ mg
13) 5.6 kg = _____ g 18) 50 cm = _____ m 23) 6.3 cm = _____ mm
14) 8 mm = _____ cm 19) 5.6 m = _____ cm 24) 120 mg = _____ g

8. Compare using <, >, or =.
25) 63 cm m 27) 5 g mg 29) 1,500 mL L
26) 536 cm dm 28) 43 mg g 30) 3.6 m cm

9. Dimensional Analysis
A mathematical way to convert one unit to another. This works for metric units and non-metric (English) units.
This works by taking the unit you are given and multiplying it by a conversion factor.

10. Metric Conversion Factors
Knowing these conversion factors makes calculating conversions easy!
These also work for liters and grams. Just replace the base unit (m) with a (g) or (l).
1 km= 1000 m
100 cm= 1 m
1000 mm = 1 m
10 mm = 1 cm

11. Example 1: Convert 3m to cm
For meters to cancel out, meters in the conversion factor must be on the opposite side of the fraction (fence). 3m
100 cm 1m
Multiply every number on top of the fence and divide by the bottom.

12. Example 2: Convert 1516 g to Kg

13. Try these yourself
Convert cm to m.

14. Try these yourself
Convert 5200mL to L.

15. Try these yourself
Convert mm to Km.