CHAPTER 2: In-Chapter Review Problems
32. Calculate the percent errors for Student B’s trials:
Trial 1: 11.9%
Trial 2: 5.66 %
Trial 3: 8.80%
33. Calculate the percent errors for Student C’s trials:
Trial 1: 6.92%
Trial 2: 6.29%
Trial 3: 7.55%
34. Based on percent error, which student’s trial was the most accurate? The least accurate?
Most accurate: Student B, Trial 2
Least accurate: Student B, Trial 1
(Only comparing student B and C, not A here)
35. Determine the number of significant figures in each measurement:
a. 4
b. 7
c. 5
d. 3
36. Determine the number of significant figures in each measurement:
a. 5
b. 3
c. 5
d. 2
37. Write the numbers 10, 100, and 1000 in scientific notation with two, three, and four
significant figures, respectively.
10
100
1000
1
2
Two significant figures:
1.0 x 10
1.0 x 10
1.0 x 103
Three significant figures:
1.00 x 101
1.00 x 102
1.00 x 103
Four significant figures:
1.000 x 101
1.000 x 102
1.000 x 103
38. Round each number to four significant figures:
a. 84,791  84,790
c. 256.75  256.8
b. 38.5432  38.54
d. 4.9356  4.936
39. Round each number to four significant figures, and write the answer in scientific notation:
a. 0.00054818  0.0005482  5.482 x 10-4
b. 136,758  136,800  1.368 x 105
c. 308,659,000  308,700,000  3.087 x 108
d. 2.0145  2.014  2.014 x 100
40. Add and subtract as indicated. Round off when necessary.
Remember: Keep the lowest number of decimal places in your answer.
a. 142.9 cm
b. 768 kg
41. Add and subtract as indicated. Round off when necessary.
a. 2.7 x 103 cm (1.6 x 104 mm is 1.6 x 103 cm)
b. 2.1 x 107 mm
(1.8 x 103 cm is 1.8 x 104 mm)
42. Perform the following calculations. Round the answers to the correct number of sig figs.
CHECK YOUR UNITS.
a. 78 m2
b. 12 m2
c. 2.5 m2
d. 81.1 m2
43. Perform the following calculations. Round the answers to the correct number of sig figs.
a. 2.0 m/s
b. 3.00 m/s
c. 2.00 m/s
d. 2.9 m/s
44. 5.3 g/cm3
BONUS: TRY QUESTIONS 45-51!!
45. A measured value is reported with all the known digits and one estimated digit.
46. Accuracy is how close a value is to the accepted value. Precision is how close a series of
measurement are to one another.
47. They each have four significant figures.
48. Answers may vary here. These measurements are not precise for values recorded to four
significant figures. The first and second values are close enough to be called accurate.
49. 0.01307 %, 0.02615%, and 0.1307%
50. 5.06000 x 105 cm
51. The mass of an individual coin calculated for each trial are:
5 coins  1 coin = 4.6 g
20 coins  1 coin = 5.3 g
10 coins  1 coin = 5.5 g
30 coins  1 coin = 5.2 g
50 coins  1 coin = 4.9 g
Knowing that the accepted value for the mass of one coin is 5.00 g, the data in the table is
too varied to be precise and differ too greatly from the accepted value to be accurate.
PAGE 63: Section 2.3 Mastering Concepts/Problems Answers
85. The first zero is significant as it’s between two non-zero digits. The last zero is not
significant as it is only a placeholder.
86. The percent error equation uses the absolute value of the error.
87. You must know the accepted value to know if the measurements are accurate. They are
fairly precise because there is only 0.14 g difference between the two measurements.
88. 3.450 and 3.448 both round to 3.45. (3.456 rounds up to 3.46)
89. 5.85 cm (This instrument is ±0.01)
90. The 242.6 is the number that has the fewest digits to the right of the decimal. It is the least
precise so the answer can only be reported to the tenths place.
91. a) 431,800 kg
b) 10,240 mg
d) 0.004384 cm or 4.384 x 10-3 cm
c) 1.035 m
e) 0.0007810 mL or 7.810 x 10-4 mL
f) 0.009864 cg or 9.864 x 10-3 cg
b) 8.20e-3
c) 74.8 dm3
d) 13.82 cm
93. a) 5.5%
b) 0
c) 3.6%
d) 7.3%
94. a) 1.12%
b) 0.446%
c) 0.446%
d) 0.223%
92. a) 7.63e4
e) 8.097 km