1. Chapter 3 Scientific Measurement 3.2 Units of Measurement
3.1 Using and Expressing
Measurements
3.2 Units of Measurement
3.3 Solving Conversion Problems
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2. Do Now: Round to three significant figures: 0.00042557 4.0235 x 10-5
Scientific Notation
Do Now: Round to three significant figures:
x 10-5
5,991,556
399.85
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3. Density: ratio of the mass of an object to its volume.
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4. Density
A block of aluminum occupies a volume of 15.0 mL and has a mass of 40.5 g. What is the density?
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5. Density
What is the mass of ethanol that exactly fills a mL container? The density of ethanol is g/mL.
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6. Density
What volume of silver metal will weigh exactly g? The density of silver is 10.5 g/cm3.
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7. Density
Do Now:
A bar of silver has a mass of 68.0 g and a volume of 6.48 cm3. What is the density of silver?
The density of aluminum is 2.7 g/cm3. What is the mass of 15 cm3 of aluminum?
The density of a substance is 5.4 g/mL. What is the volume of 25 g of this substance.
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8. Density
This figure compares the density of four substances: lithium, water, aluminum, and lead.
Increasing density (mass per unit volume)
10 g
0.53 g/cm3
19 cm3
10 cm3
3.7 cm3
0.88 cm3
1.0 g/cm3
2.7 g/cm3
11.4 g/cm3
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9. Because of differences in density, liquids separate into layers.
Corn oil floats on water because it is less dense than water.
Corn syrup sinks below water because it is more dense than water.
Corn oil
Water
Corn syrup
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10. List the units you are familiar with for
Mass Volume Length Temperature
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11. Using SI Units SI Base Units Quantity SI base unit Symbol Length meter
Mass
kilogram kg
Temperature
kelvin K
Time
second s
Amount of substance
mole
mol
Luminous intensity
candela cd
Electric current
ampere A
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12. Commonly Used Metric Prefixes
Using SI Units
Commonly Used Metric Prefixes
Prefix
Symbol
Multiplier
Factor
kilo k
1000
103
hecto h
100
102
deca da 10
101
------
-----
Base Unit
(meter, gram, liter, etc)
deci d
0.1
10-1
centi c
0.01
10-2
milli m
0.001
10-3
King Henry Died By Drinking Chocolate Milk
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13. Volume – space occupied by matter
Using SI Units
Volume – space occupied by matter
V = L x W x H
SI unit: cubic meter (m3)
Liter (L) = 10cm x 10cm x 10cm
= 1000cm3 = 1L
1mL = 1 cm3
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14. Temperature: measure of how hot or cold an object is.
Temperature Scales
Temperature: measure of how hot or cold an object is.
SI unit: Kelvin (K)
Common unit: Celsius
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15. Note: with the Kelvin scale, the degree sign is not used
Temperature Scales
Note: with the Kelvin scale, the degree sign is not used
Celsius
Kelvin
100
divisions
100°C
Boiling point
of water K
0°C
Freezing point K
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16. Temperature Scales
One degree Celsius is equivalent to one Kelvin on the Kelvin scale.
To convert between the temperature scales,
K = °C + 273
°C = K – 273
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17. Converting Between Temperature Scales
Sample Problem 3.7
Converting Between Temperature Scales
Normal human body temperature is 37°C. What is this temperature in kelvins?
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18. Commonly Used Metric Prefixes
Using SI Units
Commonly Used Metric Prefixes
Prefix
Symbol
Meaning
Factor
mega M
1 million times larger than the unit it precedes
106
kilo k
1000 times larger than the unit it precedes
103
deci d
10 times smaller than the unit it precedes
10-1
centi c
100 times smaller than the unit it precedes
10-2
milli m
1000 times smaller than the unit it precedes
10-3
micro μ
1 million times smaller than the unit it precedes
10-6
nano n
1 billion times smaller than the unit it precedes
10-9
pico p
1 trillion times smaller than the unit it precedes
10-12
All metric units are based on multiples of 10. As a result, you can convert between units easily.
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19. END OF 3.2
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