1. 1 Chapter 2 Measurements 2.1 Units of Measurement Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

3. Read your watch.

4. Take your temperature.

5. Weigh a cantaloupe.Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

7. Of the thickness of the skin fold at the waist, calipers are used.Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

8. 4 Stating a Measurement In a measurement, a number is followed by a unit. Observe the following examples of measurements: Number Unit 35 m 0.25 L 225 kg 3.4 hr

10. Used in most of the world.

13. Has the unit liter (L) in metric system.

14. Uses the unit m3(cubic meter)in the SI system.

15. Is measured using a graduated cylinder.Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

17. Is measured on a balance.

18. Has the unit gram(g)in the metric system.

19. Has the unit kilogram(kg)in the SI system.Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

21. Is measured on the Celsius (C) scale in the metric system.

22. In the SI system uses the Kelvin(K) scale.Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

24. Is based on an atomic clock that uses a frequency emitted by cesium atoms.Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

25. 11 For each of the following, indicate whether the unit describes 1) length, 2) mass, or 3) volume. ____ A. A bag of onions has a mass of 2.6 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. Learning Check

26. 12 For each of the following, indicate whether the unit describes 1) length, 2) mass, or 3) volume. 2 A. A bag of onions has a mass of 2.6 kg. 1 B. A person is 2.0 m tall. 2 C. A medication contains 0.50 g aspirin. 3 D. A bottle contains 1.5 L of water. Solution

27. 13 Learning Check Identify the measurement with an SI unit. A. John’s height is 1) 1.5 yd 2) 6 ft 3) 2.1 m B. The race was won in 1) 19.6 s 2) 14.2 min 3) 3.5 hr C. The mass of a lemon is 1) 12 oz 2) 0.145 kg 3) 0.6 lb D. The temperature is 1) 85C 2) 255 K 3) 45F

28. 14 Solution Identify the measurement with an SI unit. A. John’s height is 3) 2.1 m B. The race was won in 1) 19.6 s C. The mass of a lemon is 2) 0.145 kg D. The temperature is 2) 255 K

29. 15 STEP 1 State the given and needed units. STEP 2 Write a plan to convert the given unit to the needed unit. STEP 3 Write equalities/conversion factors that connect the units. STEP 4 Set up problem with factors to cancel units and calculate the answer. Unit 1 x Unit 2 = Unit 2 Unit 1 Given Conversion Needed unit factor unit Guide to Problem Solving (GPS)

30. 16 Setting up a Problem How many minutes are 2.5 hours? given unit = 2.5 hr needed unit = ? min plan= hr min Set up problem to cancel units (hr). given conversion needed unit factor unit 2.5 hr x 60 min = 150 min 1 hr Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

31. 17 A rattlesnake is 2.44 m long. How long is the snake in centimeters? 1) 2440 cm 2) 244 cm 3) 24.4 cm Learning Check

32. 18 A rattlesnake is 2.44 m long. How long is the snake in centimeters? 2) 244 cm given conversion needed unit factor unit 2.44 m x 100 cm = 244 cm 1 m Solution

34. 20 How many minutes are in 1.4 days? Given unit: 1.4 days Needed unit: min Plan: days hr min Equalties: 1 day = 24 hr 1 hr = 60 min Set up problem: 1.4 days x 24 hr x 60 min = 2.0 x 103 min 1 day 1 hr Example: Problem Solving

36. The units in the conversion factors must cancel to give the correct unit for the answer. What is wrong with the following setup?1.4 day x 1 day x 1 hr 24 hr 60 min Units = day2/min is Not the needed unit Units don’t cancel properly. Check the Unit Cancellation

37. More units Area m2 = m x m Volume m3 = m x m x m Density mass/volume g/mL or Kg/L 22

38. K = oC + 273 Ex 23 oC = _______ K 135 K = ________ oC 1L = 1 dm3 1 m3 =1000L Ex 27 m3 = ________ L 23

39. 24 Osmium is a very dense metal. What is its density in g/cm3 if 50.0 g of osmium has a volume of 2.22 cm3? 1) 2.25 g/cm3 2) 22.5 g/cm3 3) 111 g/cm3 Learning Check

40. 25 Given: mass = 50.0 g volume = 2.22 cm3 Plan: Write the density expression. D = mass volume Express mass in grams and volume in cm3mass = 50.0 g volume = 2.22 cm3 Set up problem using mass and volume. D = 50.0 g = 22.522522 g/cm3 2.22 cm3 = 22.5 g/cm3 Solution

42. The volume of the solid is calculated from the volume difference. 45.0 mL - 35.5 mL = 9.5 mL = 9.5 cm3 Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

43. 27 Density Using Volume Displacement The density of the object is calculated from its mass and volume. mass = 68.60 g = 7.2 g/cm3 volume 9.5 cm3 Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

46. 30 1) vegetable oil 0.91 g/mL water 1.0 g/mL Karo syrup 1.4 g/mL V W K Solution

47. 31 Chapter 2 Measurements 2.2 Scientific Notation Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

51. The spaces moved are shown as a power of ten. 52 000. = 5.2 x 1040.00378 = 3.78 x 10-3 4 spaces left 3 spaces right

52. 34 Some Powers of Ten Copyright © 2008 by Pearson Education, Inc. Publishing as Benjamin Cummings

53. 35 Comparing Numbers in Standard and Scientific Notation Number in Standard Format Scientific Notation Diameter of the Earth 12 800 000 m 1.28 x 107 m Mass of a human 68 kg 6.8 x 101 kg Mass of a hummingbird 0.002 kg 2 x 10-3 kg Length of a pox virus 0.000 000 3 cm 3 x 10-7 cm

54. 36 Learning Check Select the correct scientific notation for each. A. 0.000 008 1) 8 x 106 2) 8 x 10-6 3) 0.8 x 10-5 B. 72 000 1) 7.2 x 104 2) 72 x 103 3) 7.2 x 10-4

55. 37 Solution Select the correct scientific notation for each. A. 0.000 008 2) 8 x 10-6 B. 72 000 1) 7.2 x 104

56. 38 Learning Check Write each as a standard number. A. 2.0 x 10-2 1) 200 2) 0.00203) 0.020 B. 1.8 x 105 1) 180 000 2) 0.000 0183) 18 000

57. 39 Solution Write each as a standard number. A. 2.0 x 10-2 3) 0.020 B. 1.8 x 105 1) 180 000