1. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu 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 conversion factor. Section 2 Units of Measurement Chapter 2

2. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu QUOTE

3. End Show © Copyright Pearson Prentice Hall 3 Measurements and Their Uncertainty > Slide of 48 Using and Expressing Measurements How do measurements relate to science? 2.2

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Units of Measurement Measurements represent quantities. A quantity is something that has magnitude, size, or amount. Section 2 Units of Measurement Chapter 2

5. End Show © Copyright Pearson Prentice Hall 5 Measurements and Their Uncertainty > Slide of 48 2.2 Using and Expressing Measurements A measurement is a quantity that has both a number and a unit. Measurements are fundamental to the experimental sciences. For that reason, it is important to be able to make measurements and to decide whether a measurement is correct.

6. End Show © Copyright Pearson Prentice Hall 6 Slide of 48 2.2 The International System of Units In the signs shown here, the distances are listed as numbers with no units attached. Without the units, it is impossible to communicate the measurement to others. When you make a measurement, you must assign the correct units to the numerical value.

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Units of Measurement measurement  quantity the teaspoon is a unit of measurement volume is a quantity The choice of unit depends on the quantity being measured. Section 2 Units of Measurement Chapter 2

8. End Show Slide of 33 © Copyright Pearson Prentice Hall 8 The International System of Units > Measuring with SI Units Which five SI base units do chemists commonly use? 2.2

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu SI Measurement Scientists all over the world have agreed on a single measurement system called Le Système International d’Unités, abbreviated SI which is a revised version of the metric system. Section 2 Units of Measurement Chapter 2 SI has seven base units most other units are derived from these seven

10. End Show Slide of 33 © Copyright Pearson Prentice Hall 10 The International System of Units > 2.2 Measuring with SI Units The five SI base units commonly used by chemists are the meter, the kilogram, the kelvin, the second, and the mole. (Put an asterisks by these in chart.)

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts SI (Le Syst éme International d´Unités) Chapter 2 Celsius

12. End Show © Copyright Pearson Prentice Hall 12 Slide of 33 The International System of Units > 2.2 Units and Quantities What metric units are commonly used to measure mass, length, volume, temperature and energy?

13. End Show Slide of 33 © Copyright Pearson Prentice Hall 13 The International System of Units > 2.2 Units and Quantities Units of Mass The mass of an object is measured in comparison to a standard mass of 1 kilogram (kg), which is the basic SI unit of mass. A gram (g) is 1/1000 of a kilogram; the mass of 1 cm 3 of water at 4°C is 1 g.

14. End Show Slide of 33 © Copyright Pearson Prentice Hall 14 The International System of Units > 2.2 Units and Quantities Common metric units of mass include kilogram, gram, milligram, and microgram.

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu SI Base Units Mass Mass is a measure of the quantity of matter. The SI standard unit for mass is the kilogram. Grams are used to measure the mass of smaller objects. Section 2 Units of Measurement Chapter 2

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu SI Base Units Length The SI standard for length is the meter. Length is a measure of distance. The kilometer, km, is used to express longer distances The centimeter, cm, is used to express shorter distances Section 2 Units of Measurement Chapter 2

17. End Show Slide of 33 © Copyright Pearson Prentice Hall 17 The International System of Units > 2.2 Units and Quantities Units of Length In SI, the basic unit of length, or linear measure, is the meter (m). For very large or and very small lengths, it may be more convenient to use a unit of length that has a prefix.

18. End Show Slide of 33 © Copyright Pearson Prentice Hall 18 The International System of Units > 2.2 Units and Quantities Common metric units of length include the centimeter, meter, and kilometer.

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu SI base Units, continued Volume Volume is the amount of space occupied by an object. The derived SI unit is cubic meters, m 3 The cubic centimeter, cm 3, is often used The liter, L, is a non-SI unit 1 L = 1000 cm 3 1 mL = 1 cm 3 Section 2 Units of Measurement Chapter 2

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Volume Chapter 2 http://my.hrw.com/sh/hc6_0030 36809x/student/ch02/sec02/vc0 1/hc602_02_v01fs.htm

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Measuring the Volume of Liquids Chapter 2 http://my.hrw.com/sh/hc6_003036809x /student/ch02/sec02/vc02/hc602_02_v0 2fs.htm

22. End Show Slide of 33 © Copyright Pearson Prentice Hall 22 The International System of Units > 2.2 Units and Quantities Units of Volume The SI unit of volume is the amount of space occupied by a cube that is 1 m along each edge. This volume is the cubic meter (m) 3. A more convenient unit of volume for everyday use is the liter, a non-SI unit. A liter (L) is the volume of a cube that is 10 centimeters (10 cm) along each edge (10 cm  10 cm  10 cm = 1000 cm 3 = 1 L).

23. End Show Slide of 33 © Copyright Pearson Prentice Hall 23 The International System of Units > 2.2 Units and Quantities Common metric units of volume include the liter, milliliter, cubic centimeter, and microliter.

24. End Show Slide of 33 © Copyright Pearson Prentice Hall 24 The International System of Units > 2.2 Units and Quantities The volume of 20 drops of liquid from a medicine dropper is approximately 1 mL.

25. End Show Slide of 33 © Copyright Pearson Prentice Hall 25 The International System of Units > 2.2 Units and Quantities A sugar cube has a volume of 1 cm 3. 1 mL is the same as 1 cm 3.

26. End Show Slide of 33 © Copyright Pearson Prentice Hall 26 The International System of Units > 2.2 Units and Quantities A gallon of milk has about twice the volume of a 2-L bottle of soda.

27. End Show Slide of 33 © Copyright Pearson Prentice Hall 27 The International System of Units > 2.2 2 Units and Quantities Units of Temperature Temperature is a measure of how hot or cold an object is. Thermometers are used to measure temperature.

28. End Show Slide of 33 © Copyright Pearson Prentice Hall 28 The International System of Units > 2.2 Units and Quantities Scientists commonly use two equivalent units of temperature, the degree Celsius and the kelvin.

29. End Show Slide of 33 © Copyright Pearson Prentice Hall 29 The International System of Units > 2.2 Units and Quantities On the Celsius scale, the freezing point of water is 0°C and the boiling point is 100°C. On the Kelvin scale, the freezing point of water is 273.15 kelvins (K), and the boiling point is 373.15 K. The zero point on the Kelvin scale, 0 K, or absolute zero, is equal to −273.15 °C.

30. End Show Slide of 33 © Copyright Pearson Prentice Hall 30 The International System of Units > 2.2 Units and Quantities Because one degree on the Celsius scale is equivalent to one kelvin on the Kelvin scale, converting from one temperature to another is easy. You simply add or subtract 273, as shown in the following equations.

31. End Show Slide of 33 © Copyright Pearson Prentice Hall 31 The International System of Units > 2.2 Units and Quantities Conversions Between the Celsius and Kelvin Scales

32. © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide of 33 End Show 3.4

33. © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide of 33 End Show 3.4

34. © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide of 33 End Show 3.4

35. © Copyright Pearson Prentice Hall SAMPLE PROBLEM Slide of 33 End Show 3.4

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Derived SI Units Combinations of SI base units form derived units. pressure is measured in kg/ms 2, or pascals Section 2 Units of Measurement Chapter 2

37. End Show Slide of 33 © Copyright Pearson Prentice Hall 37 The International System of Units > 2.2 Units and Quantities Weight is a force that measures the pull on a given mass by gravity. The astronaut shown on the surface of the moon weighs one sixth of what he weighs on Earth.

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu SI Derived Units Weight Weight is a measure of the gravitational pull on matter. Mass does not depend on gravity and is measured with a balance. Weight is measured with a spring scale in Newtons and is a type of force. Section 2 Units of Measurement Chapter 2

39. End Show Slide of 33 © Copyright Pearson Prentice Hall 39 The International System of Units > 2.2 Units and Quantities Units of Energy Energy is the capacity to do work or to produce heat. The joule and the calorie are common units of energy.

40. End Show Slide of 33 © Copyright Pearson Prentice Hall 40 The International System of Units > 2.2 Units and Quantities The joule (J) is the SI unit of energy. One calorie (cal) is the quantity of heat that raises the temperature of 1 g of pure water by 1°C.

41. End Show © Copyright Pearson Prentice Hall 41 Slide of 25 Density If you think that these lily pads float because they are lightweight, you are only partially correct. The ratio of the mass of an object to its volume can be used to determine whether an object floats or sinks in water. 2.2B

42. End Show © Copyright Pearson Prentice Hall 42 Density > Slide of 25 Determining Density What determines the density of a substance? 2.2B

43. End Show © Copyright Pearson Prentice Hall 43 Slide of 25 Density > Determining Density Density is the ratio of the mass of an object to its volume. 2.2B

44. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Derived SI Units, continued Density Density is the ratio of mass to volume, or mass divided by volume. Section 2 Units of Measurement Chapter 2 The derived SI unit is kilograms per cubic meter, kg/m 3 g/cm 3 or g/mL are also used Density is a characteristic physical property of a substance.

45. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Derived SI Units, continued Density Density can be used as one property to help identify a substance Section 2 Units of Measurement Chapter 2

46. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu DENSITY & VOLUME PROBLEM ACTIVITIES PROBLEM ACTIVITY #1 - DENSITY CLICK HERE FOR DENSITY PROBLEM ACTIVITY PROBLEM ACTIVITY #2 - VOLUME CLICK HERE FOR VOLUME CALCULATIONS WITH DENSITY

47. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Visual Concepts Click below to watch the Visual Concept. Visual Concept Equation for Density Chapter 2 http://my.hrw.com/sh/hc6_003036809x/student/ ch02/sec02/vc04/hc602_02_v04fs.htm

48. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Sample Problem A A sample of aluminum metal has a mass of 8.4 g. The volume of the sample is 3.1 cm 3. Calculate the density of aluminum. Section 2 Units of Measurement Chapter 2 Derived SI Units, continued

49. Copyright © by Holt, Rinehart and Winston. All rights reserved. ResourcesChapter menu Derived SI Units, continued Sample Problem A Solution Given: mass (m) = 8.4 g volume (V) = 3.1 cm 3 Section 2 Units of Measurement Chapter 2 Solution: Unknown: density (D)

50. End Show © Copyright Pearson Prentice Hall 50 Slide of 25 Density > Determining Density Density is an intensive property that depends only on the composition of a substance, not on the size of the sample. 2.2B

51. End Show © Copyright Pearson Prentice Hall 51 Slide of 25 Density > Determining Density The density of corn oil is less than the density of corn syrup. For that reason, the oil floats on top of the syrup. 2.2B

52. End Show © Copyright Pearson Prentice Hall 52 Density > Slide of 25 Density and Temperature How does a change in temperature affect density? 2.2B

53. End Show Slide of 25 © Copyright Pearson Prentice Hall 53 Density > Density and Temperature Experiments show that the volume of most substances increases as the temperature increases. Meanwhile, the mass remains the same. Thus, the density must change. The density of a substance generally decreases as its temperature increases. 2.2B

54. End Show © Copyright Pearson Prentice Hall Slide of 33 Section Quiz -or- Continue to: Launch: Assess students’ understanding of the concepts in Section 2.2 A&B Section Quiz. 2.2.

55. © Copyright Pearson Prentice Hall Slide of 27 End Show 2.2 A Section Quiz. 1. Which of the following is not a base SI unit? a.meter b.gram c.second d.mole

56. © Copyright Pearson Prentice Hall Slide of 27 End Show 2.2 A Section Quiz. 2. If you measured both the mass and weight of an object on Earth and on the moon, you would find that a.both the mass and the weight do not change. b.both the mass and the weight change. c.the mass remains the same, but the weight changes. d.the mass changes, but the weight remains the same.

57. © Copyright Pearson Prentice Hall Slide of 27 End Show 2.2 A Section Quiz. 3. A temperature of 30 degrees Celsius is equivalent to a.303 K. b.300 K. c.243 K. d.247 K.

58. End Show © Copyright Pearson Prentice Hall Slide of 25 Section Quiz -or- Continue to: Launch: Assess students’ understanding of the concepts in Section Section Assessment 2.2B 3.4

59. © Copyright Pearson Prentice Hall Slide of 27 End Show 2.2 B Section Quiz 4. If 50.0 mL of corn syrup have a mass of 68.7 g, the density of the corn syrup is a.0.737 g/mL. b.0.727 g/mL. c.1.36 g/mL. d.1.37 g/mL.

60. © Copyright Pearson Prentice Hall Slide of 27 End Show 2.2 B Section Quiz 5. What is the volume of a pure gold coin that has a mass of 38.6 g? The density of gold is 19.3 g/cm 3. a.0.500 cm 3 b.2.00 cm 3 c.38.6 cm 3 d.745 cm 3

61. © Copyright Pearson Prentice Hall Slide of 27 End Show 2.2 B Section Quiz 6. As the temperature increases, the density of most substances a.increases. b.decreases. c.remains the same. d.increases at first and then decreases.

62. © Copyright Pearson Prentice Hall Slide of 25 End Show Online Self-Check Quiz Complete the online 2.2 Quiz and record answers. Ask if you have any questions about your answers. Click here for Section 2.2 QUIZClick here for Section 2.2 QUIZ(8 questions) You must be in the “Play mode” for the slideshow for hyperlink to work.