1. Chapter 2 Preview Objectives Units of Measurement SI Measurement
Section 2 Units of Measurement
Chapter 2
Preview
Objectives
Units of Measurement
SI Measurement
SI Base Units
Derived SI Units
Conversion Factors

2. Chapter Vocabulary
6. quantity 7. SI 8. weight 9. derived unit 10. volume 11. density 12. conversion factor 13. dimensional analysis

3. Chapter 2
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4. Section 2 Units of Measurement
Chapter 2
Objectives
Distinguish between a quantity, a unit, and a measurement standard.
Name and use SI units for length, mass, time, volume, and density.
Distinguish between mass and weight.
Perform density calculations.
Transform a statement of equality into a conversion factor.

5. Chapter 2 Units of Measurement Measurements represent quantities.
Section 2 Units of Measurement
Chapter 2
Units of Measurement
Measurements represent quantities.
A quantity is something that has magnitude, size, or amount.
measurement  quantity
the teaspoon is a unit of measurement
volume is a quantity
The choice of unit depends on the quantity being measured.

6. Chapter 2 SI Measurement
Section 2 Units of Measurement
Chapter 2
SI Measurement
Scientists all over the world have agreed on a single measurement system called Le Système International d’Unités, abbreviated SI.
SI has seven base units
most other units are derived from these seven

7. Section 2 Units of Measurement
Chapter 2
C. SI Base Units

8. C. SI base Units *All other units are derived units Quantity Symbol
1. Length l
meter m
2. Mass
kilogram kg
3. Temperature T
kelvin K
4. Time t
second s
5. Amount of substance n
mole
mol
6. Luminous intensity Iv
candela cd
7. Electric current I
ampere A
*All other units are derived units

9. 2.2 The International System of Units (SI)

10. D. SI Prefixes

11. Prefix Abbreviation Meaning Exponent
D. SI prefixes
Prefix
Abbreviation
Meaning
Exponent
Mega- M
Million
106
Kilo- k
thousand
103
Deci- d
tenth
10-1
Centi- c
hundredth
10-2
Milli- m
thousandth
10-3
Micro- 
millionth
10-6
Nano- n
billionth
10-9
Pico- p
trillionth
10-12

12. Chapter 2 SI Base Units Mass
Section 2 Units of Measurement
Chapter 2
SI Base Units
Mass
Mass is a measure of the quantity of matter.
The SI standard unit for mass is the kilogram.
Weight is a measure of the gravitational pull on matter.
Mass does not depend on gravity.

13. Chapter 2 SI Base Units Length Length is a measure of distance.
Section 2 Units of Measurement
Chapter 2
SI Base Units
Length
Length is a measure of distance.
The SI standard for length is the meter.
The kilometer, km, is used to express longer distances
The centimeter, cm, is used to express shorter distances

14. Chapter 2 E. Derived SI Units
Section 2 Units of Measurement
Chapter 2
E. Derived SI Units
Combinations of SI base units form derived units.
pressure is measured in kg/m•s2, or pascals

15. Derived SI Units, continued
Section 2 Units of Measurement
Chapter 2
Derived SI Units, continued
Volume
Volume is the amount of space occupied by an object.
The derived SI unit is cubic meters, m3
The cubic centimeter, cm3, is often used
The liter, L, is a non-SI unit
1 L = 1000 cm3
1 mL = 1 cm3

16. Derived SI Units, continued
Section 2 Units of Measurement
Chapter 2
Derived SI Units, continued
Density
Density is the ratio of mass to volume, or mass divided by volume.
The derived SI unit is kilograms per cubic meter, kg/m3
g/cm3 or g/mL are also used
Density is a characteristic physical property of a substance.

17. Notecard: Density Formula
Chapter 2
Section 2 Units of Measurement
Notecard: Density Formula
Density:
D =
Volume:
V =
Mass: m V mD
m = D x V

18. Derived SI Units, continued
Section 2 Units of Measurement
Chapter 2
Derived SI Units, continued
Density
Density can be used as one property to help identify a substance

19. Derived SI Units, continued
Section 2 Units of Measurement
Chapter 2
Derived SI Units, continued
Sample Problem A (p.37)
A sample of aluminum metal has a mass of
8.4 g. The volume of the sample is 3.1 cm3. Calculate the density of aluminum.

20. Derived SI Units, continued
Section 2 Units of Measurement
Chapter 2
Derived SI Units, continued
Sample Problem A Solution
Given: mass (m) = 8.4 g
volume (V) = 3.1 cm3
Unknown: density (D)
Solution:

21. 2.2 Practice Problems Chapter 2 Set A (p.38)
Section 2 Units of Measurement
2.2 Practice Problems
Set A (p.38)
1. What is the density of a block of marble that occupies
310.cm3 and has a mass of 853g?

22. 2.2 Practice Problems Chapter 2 Set A (p.38)
Section 2 Units of Measurement
2.2 Practice Problems
Set A (p.38)
2. Diamond has a density of 3.26 g/cm3. What is the mass of a diamond that has a volume of 0.351cm3?

23. 2.2 Practice Problems Chapter 2 Set A (p.38)
Section 2 Units of Measurement
2.2 Practice Problems
Set A (p.38)
3. What is the volume of a sample of liquid mercury that has a mass of 76.2g, given that the density of mercury is 13.6g/mL?

24. Chapter 2 Conversion Factors
Section 2 Units of Measurement
Chapter 2
Conversion Factors
A conversion factor is a ratio derived from the equality between two different units that can be used to convert from one unit to the other.
example: How quarters and dollars are related

25. Conversion Factors, continued
Section 2 Units of Measurement
Chapter 2
Conversion Factors, continued
Dimensional analysis is a mathematical technique that allows you to use units to solve problems involving measurements.
quantity sought = quantity given × conversion factor
example: the number of quarters in 12 dollars
number of quarters = 12 dollars × conversion factor

26. Using Conversion Factors
Section 2 Units of Measurement
Chapter 2
Using Conversion Factors

27. Conversion Factors, continued
Section 2 Units of Measurement
Chapter 2
Conversion Factors, continued
Deriving Conversion Factors
You can derive conversion factors if you know the relationship between the unit you have and the unit you want.
example: conversion factors for meters and decimeters

28. Section 2 Units of Measurement
Chapter 2
SI Conversions

29. Conversion Factors, continued
Section 2 Units of Measurement
Chapter 2
Conversion Factors, continued
Sample Problem B (p. 41-2)
Express a mass of grams in milligrams and in kilograms.

30. Conversion Factors, continued
Section 2 Units of Measurement
Chapter 2
Conversion Factors, continued
Sample Problem B Solution
Express a mass of grams in milligrams and in kilograms.
Given: g
Unknown: mass in mg and kg
Solution: mg
1 g = 1000 mg
Possible conversion factors:

31. Conversion Factors, continued
Section 2 Units of Measurement
Chapter 2
Conversion Factors, continued
Sample Problem B Solution, continued
Express a mass of grams in milligrams and in kilograms.
Given: g
Unknown: mass in mg and kg
Solution: kg
1 000 g = 1 kg
Possible conversion factors:

32. 2.2 Practice Problems Chapter 2 Set B (p.40)
Section 2 Units of Measurement
2.2 Practice Problems
Set B (p.40)
1. Express a length of m in centimeters and in kilometers.

33. 2.2 Practice Problems Chapter 2 Set B (p.40)
Section 2 Units of Measurement
2.2 Practice Problems
Set B (p.40)
2. Express a mass of mg in grams.

34. 2.2 Practice Problems Chapter 2 Set B (additional)
Section 2 Units of Measurement
2.2 Practice Problems
Set B (additional)
3. Would you be breaking the speed limit in a 40 mi/h zone if you were traveling at 60 km/h? Show work.
one kilometer = 0.62 miles

35. 2.2 Practice Problems (additional problem)
Section 2 Units of Measurement
Chapter 2
2.2 Practice Problems (additional problem)
3. Would you be breaking the speed limit in a 40 mi/h zone if you were traveling at 60 km/h?
one kilometer = 0.62 miles
60 km/h = 37 mi/h
You would not be speeding!
km/h and mi/h measure the same quantity using different units

36. 2.2 Practice Problems (additional)
Chapter 2
Section 2 Units of Measurement
2.2 Practice Problems (additional)
Set C (p. 58)
16-23

37. Section 2 Units of Measurement
Chapter 2
Objectives
Distinguish between a quantity, a unit, and a measurement standard.
Name and use SI units for length, mass, time, volume, and density.
Distinguish between mass and weight.
Perform density calculations.
Transform a statement of equality into a conversion factor.

38. Chapter Vocabulary
6. quantity 7. SI 8. weight 9. derived unit 10. volume 11. density 12. conversion factor 13. dimensional analysis

39. End of Section 2 Show