1. Measurement in Chemistry
SI (Metric System) Units
Prefixes
Factor Label Method
Equipment
Using density for identification and applications

2. 2. Measurement in Chemistry
Measurements in chemistry always require a ________________ & a ________________.
NO ___________________ numbers!
We use the International System (SI), which is similar to the metric system:

3. SI Units Quantity Common unit Measurement Equipment Mass Length Time
Temperature

4. SI Temperature: Celsius or Kelvin

5. SI Units Quantity Common Unit Measurement Equipment
Amount of Substance
Energy
Volume of a Liquid
Volume of a
Solid

6. Small and large units Metric System: Similar system but using prefixes
Everyday units (English System)
Length
Paperclip:
Laptop
Whiteboard
Sandy Porter Road
Metric System: Similar system but using prefixes

7. Small and large measurements
SI System: Based on Powers of Ten

8. Important SI Prefixes Kilo- k Hecto h Deka- da Base Decid Centi- c
Milli- m
1000
100 10 1
0.1
0.01
0.001
10³
10²
10¹
10°
10⁻¹
10⁻²
10⁻³
1 meter
1 Liter
1 gram

9. Equivalent amounts - Memorize!
1 kilometer (_____) = _______ meters
1 hectometer ( ) = ________ meters
1 dekameters ( ) = ________ meters
1 meter = ________ decimeters
1 meter = ________ centimeters
1 meter = ________ millimeter

10. Memory tool: King Henry Died by Drinking Chocolate Milk

11. Measurements in chemistry calculations must have the same ____and ______.
To covert:
Given Quantity x Conversion Factor = Unknown (or desired) Quantity
A known beginning=
A desired end=
A connecting path=

12. Factor Label Method
Please note: There are other ways to do the metric conversions. However, the following method will be used in chemistry to help prepare for the more difficult mole calculations, which will be in the next unit. Use the other methods to check your answers.

13. The most important mathematical process in chemistry!
Factor Label Method
The most important mathematical process in chemistry!
A known beginning = GIVEN
A desired end= UNKNOWN
A connecting path = CONVERSION FACTOR

14. Conversion Factor Uses equal quantities 60 seconds = 1 minute
1 km = 1000 meters
Conversion factors can be written as ratios
Ratios are written as “tops or bottoms” depending on the units to be cancelled.

15. Example: How many centimeters are in 6.4 meters?

16. 1. How many grams are in 463 kilograms? Given: Unknown:
Example Problems: Given quantity & unit x Unknown unit = Unknown quantity & unit Given unit
1. How many grams are in 463 kilograms?
Given:
Unknown:
Conversion factor:
Solve:

17. 2. How many milliliters are in 2.5 liters? Given: Unknown:
Example Problems: Given quantity & unit x Unknown unit = Unknown quantity & unit Given unit
2. How many milliliters are in 2.5 liters?
Given:
Unknown:
Conversion factor:
Solve:

18. 3. How many meter(s) are equal to 16 centimeters? Given: Unknown:
Example Problems: Given quantity & unit x Unknown unit = Unknown quantity & unit Given unit
3. How many meter(s) are equal to 16 centimeters?
Given:
Unknown:
Conversion factor:
Solve:

19. Factor Label - Multiple steps example
Calculate the number of seconds in one day.
60 seconds = 1 minute
60 minutes = 1 hour
24 hours = 1 day
Given Desired = sec
1 day hr. 60 min. 60 sec =
1 day hr min.

20. If you are changing prefixes for a measurement:
Size of the number (quantity)
Small
Big
S ↔ B
Larger
Prefix for
the Unit
Unit Prefix
Smaller Prefix for the Unit
Double check your answers!

21. SI Prefixes