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Unit IV: Measurements in Chemistry
Pretest
Learning Targets 1, 2, 3 & 4
Multiple Choice
Identify the letter of the choice that best completes the statement or answers
the question. (2 pts. Each)
1. What is the SI base unit for mass?
a. kilogram
c. liter
b. mole
d. gram
2. In which of the following is the zero not significant?
a. 0.15
c. 1.50
b. 1.05
d. 1.015
3. A meter is defined as 100 cm. How many significant digits are there in
the value 100?
a. one
c. three
b. two
d. an infinite number
4. Which of these measurements is expressed to three significant figures?
a. 0.070 mm
c. 7077 mg
-7
b. 7.30 X 10 km
d. 0.007 m
5. A student measures a volume as 25 mL, whereas the correct volume is
23 mL. What is the percent error?
a. 0.087 %
c. 0.92 %
b. 8.7 %
d. 8.0 %
6. The measurement 4.06 x 10-5 g represents:
a. 0.0000406 g
c. 406000 g
b. 0.00000406 g
d. 4060000 g
7. How many centimeters are in 25 kilometers?
a. 2.5 x 103 cm
c. 2.5 x 105 cm
b. 2.5 x 104 cm
d. 2.5 x 106 cm
8. The smallest volume from among the following is:
a. 0.012 L
c. 18 cm3
b. 25 mL
d. 1.6 x 10-2 L
9. What is the density of an object with a mass of 40.0 g and a volume of
80.0 cm3?
a. 0.500 g/cm3
c. 3.20 x 103 g/cm3
b. 2.00 g/cm3
d. 1.20 x 102 g/cm3
10. What is the volume of 25.0 g of copper if the density of copper is 8.9
g/cm3?
a. 2.8 cm3
c. 220 cm3
b. 0.36 cm3
d. 34 cm3
11. The closeness of a measurement to its true value is a measure of its:
a. precision
c. accuracy
b. reproducibility
d. usefulness
Problems
Solve the following problems in the space provide. Show your work.
(Remember: No Naked Numbers)
12. How many significant figures are there in each of the following
measurements? (2 pts. Each)
a. 3.58 g
_______3________
b. 14.809 cm
_______5________
c. 107.334 km
_______6________
d. 00004898 mm
_______4________
e. 3000. L
_______4________
13. Perform the following operations. Make sure that your answers have the
correct number of significant figures. (No Naked Numbers) (2 pts. Each)
a. 3.43 cm X 5.2 cm
18 cm2
b. 18.00 km – 0.38 km
17.62 km
c. (8.74 X 109 m)/ (.2 X 10-6 m)
4 x 1016
d. 148.576 g – 35.41 g
113.17 g
14. Round of the following measurements to two significant figures: (2 pts.
Each)
a. 0.0719 m
_____0.072_________
b. 75.12 L
_____75_________
c. 5403 km
_____5400_________
15. Write the following numbers in scientific notation. (2 pts. Each)
a. 1,000,000 cm
_____1 x 106_________
b. 0.0008 mL
_____8 x 10-4_________
c. 0.0025 km
_____2.5 x 10-3_________
d. 5000 s
_____5 x 103_________
16. Perform the following unit conversions. Show your work. (2 pts. Each)
a. 18.69 m to ft.
18.69 m 100 cm
1m
1 in.
2.54 cm
1 ft.
12 in.
= 61.32 ft.
b. 190 kg to mg
190 kg
1000 g
1 kg
1000 mg
1g
= 1.9 x 108 or 190,000,000 mg
c. 45 km to inches.
45 km
1000 m
1 km
100 cm
1m
1 in.
2.54 cm
= 1.77 x 106 or 1,770,000 in.
d. 2.7 hrs to milliseconds.
2.7 hrs
60 min
1 hr
60 sec
1 min
1000 ms
1 sec
= 9,720,000 or 9.72 x 106 ms
Problems
Solve the following problems in the space provided. Show your work. (No
Naked Numbers) (5 pts. Each)
17. A cube of a gold-colored metal with a volume of 54 cm3 has a mass of
980 g. The density of pure gold is 19.3 g/cm3. Is the metal pure gold?
980 g
No. The metal is not pure gold.
54 cm3 = 18.1 g/cm3
18. Perform the following conversion.
75 miles/hr to m/s
75 miles 1 hr
1 min 5280 ft 12 in
1 hour
60 min 60 sec 1 mile 1 ft
2.54 cm 1 m
1 in
100 cm
= 33.5 m/s
19. Chloroform is a liquid with a sticky sweet odor that was once used as a
surgical anesthetic. If the density of chloroform is 1.49 g/cm3, what is
the volume of 25 g of chloroform?
25 g
1.49 g/cm3
= 16.7 cm3 or 17 cm3
20. The density of copper is 8.96 g/cm3. If a rectangular sheet of copper is
10.3 cm wide, 46.1 cm long, and 0.14 cm thick, what is the mass of the
copper?
(8.96 g/cm3 ) x (10.3 cm) x (46.1 cm) x ( 0.14 cm) = 596 g
Essay (10 pts.)
25. Discuss the relative advantages and disadvantages associated with the
conversion of the United States to the metric system. Give at least two
advantages and two disadvantages.
Answers will vary.
Examples: Cost, Time, Education, etc.