1. Measurement In Chemistry

2. Measurement At the conclusion of our time together, you should be able to:
Explain the difference between the two types of observations
Give examples of 5 basic SI measuring units
Give examples of 3 different derived units from the basic SI units
Vary the amounts of the SI measuring units with 10 different prefixes and define each
Explain the difference between mass and weight
List and explain 5 different units for volume.

3. Types of Observations and Measurements
We make QUALITATIVE observations of reactions — changes in color and physical state.
We also make QUANTITATIVE observations that involve MEASUREMENTS with numbers and units.

4. Some Tools for Measurement
Which tool(s) would you use to measure:
A. temperature
B. volume
C. time
D. weight

5. Stating a Quantitative Measurement
In every measurement there is a
Number (Quantity) followed by a
Unit from a measuring device

6. Quantitative Measurements in Chemistry Must Include Units!

7. Standards of Quantitative Measurement
When we measure, we use a measuring tool to compare some dimension of an object to a standard.
For example, at one time the standard for length was the king’s foot. What are some problems with this standard?

8. Information from U.S. Metric Association
SI Measurement
Le Système International d‘Unités
Adopted in 1960 by the General Conference on Weights and Measures.
International Standards are kept in France.
Among countries with non-metric usage, the U.S. is the only country significantly holding out. The U.S. officially adopted SI in 1866.
Liberia and Myanmar are changing over.
Liberia
Information from U.S. Metric Association

9. Base SI Units Quantity Unit Symbol Length meter m Mass kilogram kg
Temperature
kelvin K
Time
second s
Amount of Substance
mole
mol
Luminous Intensity
candela cd
Electric Current
ampere a

10. Units Of Measurement You Must Know
Use SI units — based on the metric system Length Mass Volume Time Temperature
meter, m
kilogram, kg
liter, L
seconds, s
kelvin, K

11. Unit for Length
1 Meter Note: Not Foot!!

12. Metric Prefixes Kilo- means 1000 of that unit
1 kilometer (km) = meters (m)
Centi- means 1/100 of that unit
1 meter (m) = centimeters (cm)
1 dollar = cents
Milli- means 1/1000 of that unit
1 meter (m) = millimeters (mm)

13. Metric Prefixes

14. Grand Master King Henry Died by Drinking Chocolate Milk Monday Night
Metric Prefixes
You Will Need to Know:
Grand Master King Henry Died by Drinking Chocolate Milk Monday Night

15. Metric Prefixes You Need to Know

16. 103 meters = 1 km
1 kilometer (km)
1 meter (m)
1 dm (decimeter)
10 dm = 1 m
1 cm (centimeter)
100 cm = 1 m
1 mm (millimeter)
103 mm = 1 m
1 m (micrometer)
106 m = 1 m
1 nm (nanometer)
109 nm = 1 m

17. 1 Kilogram Note: Not Gram!!
Unit for Mass
1 Kilogram Note: Not Gram!!

18. Unit for Weight
1 Newton 1 N = kg m/s2

19. A Weighty Problem
On 9/23/99, $125,000,000 Mars Climate Orbiter entered Mars’ atmosphere 100 km lower than planned and was destroyed by heat.
1 lb = 1 N
1 lb = 4.45 N
“This is going to be the cautionary tale that will be embedded into introduction to the metric system in elementary school, high school, and college science courses ‘till the end of time.”

20. Mass is a measure of the amount of matter in an object.
Mass and Weight
Weight is force of the gravitational pull on an object. It would be different on the moon than it is on earth.
Mass is a measure of the amount of matter in an object.
Mass and weight are directly related as long as we remain on earth at the same elevation. That is, if one object has twice the mass of another, then its weight on earth would also be twice as large.
However, if we take the same object to Denver, Colorado, the mass stays the same but the weight would be different. Why??

21. Mass vs. Weight Mass: Amount of Matter
(grams, measured with a BALANCE)
Weight: Force exerted by the mass, only present with gravity
(pounds, measured with a Scale)
Can you hear me now?

22. Unit for Volume
1 Meter Cubed Note: A Derived Unit!! To Big, So Generally Use the Liter

23. What is a Liter??

24. Length and Volume 1 m = 10 dm therefore 1 m3 = 103 dm3 1 dm = 10 cm
therefore dm3 = 103 cm3
1 L = 1 dm and L = 103 mL so
1 L = 1 dm3 = 103 mL = 103 cm3 = 103 cc so
This means that 1 milliliter (mL) is the same as cubic centimeter (cc). These terms are often used interchangeably.

25. Units for Volume
m3 cm3 dm3 L Liter mL
1 dm3 = 1 L 1 cm3 = 1 mL

26. kilograms per cubic meter
Other Derived SI Units
Quantity
Unit
Symbol
Volume
cubic meter m3
Density
kilograms per cubic meter
kg/m3
Speed
meter per second
m/s
Newton
kg m/ s2 N
Energy
Joule (kg m2/s2) J
Pressure
Pascal (kg/ms2) Pa

27. Units for Energy Joule J calorie 1 cal = 4.184 J
1 cal = quantity of heat needed to raise the temperature of 1 g of water by 1 oC.
1 kcal = 1000 cal

28. Measurement Let’s see if you can:
Explain the difference between the two types of observations
Give examples of 5 basic SI measuring units
Give examples of 3 different derived units from the basic SI units
Vary the amounts of the SI measuring units with 10 different prefixes and define each
Explain the difference between mass and weight
List and explain 5 different units for volume.

29. Learning Check
Match L) length M) mass V) volume ____ A. A bag of tomatoes is 4.6 kg. ____ B. A person is 2.0 m tall. ____ C. A medication contains 0.50 g Aspirin. ____ D. A bottle contains 1.5 L of water. M L M V

30. Learning Check
What are some U.S. units that are used to measure each of the following? A. length B. volume C. weight D. temperature

31. Which Metric Prefix is Generally Used?

32. Learning Check
m = 1 ___ a) mm b) km c) dm g = 1 ___ a) mg b) kg c) dg L = 1 ___ a) mL b) cL c) dL m = 1 ___ a) mm b) cm c) dm

33. Learning Check
Select the unit you would use to measure 1. Your height a) millimeters b) meters c) kilometers 2. Your mass a) milligrams b) grams c) kilograms 3. The distance between two cities a) millimeters b) meters c) kilometers 4. The width of an artery