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Chapter 2
19.
a. (28.0cm)(1M/100cm) = 0.280M
b. (1000.M)(1KM/1000M) = 1.000KM
c. (9.28cm)(10mm/1cm) = 92.8mm
d. (10.68g)(1000mg/1g) = 10680mg
e. (6.8 X 104mg)(1g/1000mg)(1kg/1000g) = 0.068kg
f. (8.54g)(1kg/1000g) = 0.00854kg
g. (25.0ml)(1L/1000ml) = 0.0250L
h. (22.4L)(1X106µL/1L) = 2.24 X107µL
20.
a. (4.5cm)(1X1010Å/100cm) = 4.5 X 108Å
b. (12nm)(100cm/1 X 109nm) = 1.2 X 10-6cm
c. (8.0km)(1000M/1km)(1000mm/1M) = 8.0 X 106mm
d. (164mg)(1g/1000mg) = 0.164g
e. (0.65kg)(1000g/1kg)(1000mg/1g) = 650,000mg
f. (5.5kg)(1000g/1kg) = 5500g
g. (0.468L)(1000ml/1L) = 468ml
h. (9.0µL)(1000ml/1 X 106µL) = 0.0090ml or 9.0 X 10-3ml
21.
a. (42.2in)(2.54cm/1in) = 107cm
b. (0.64M)(100cm/1M)(1in/2.54cm) = 25in
c. (2.00in2)(6.4516cm2/1in2) = 12.9cm2
d. (42.8kg)(1000g/1kg)(1lb/453.59g) = 94.4lb
e. (3.5qt)(1gal/4qt)(3.785L/1gal)(1000ml/1L) = 3300ml
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f. (20.0L)(1gal/3.785L) = 5.28gal
22.
a. (35.6M)(100cm/1M)(1in/2.54cm)(1ft/12in) = 117ft
b. (16.5km)(1mi/1.609km) = 10.3mi
c. (4.5in3)(16.39cm3/in3)(1000mm3/1cm3) = 7.4 X 104 mm3
d. (95g)(1 lb/453.59g) = 0.21 lb
e. (20.0gal)(3.785L/1gal) = 75.7L
f. (4.5 X 104 ft3)(1728in3/ft3)(16.39cm3/in3)(1M3/1 X 106cm3) = 1.3 X 103M3
26.
(0.500g)(1000mg/1g)(1grain/60mg) = 8.33grain
40.
(200cm3)(1M3/1 X 106cm3) = 2 X 10-4M3 and (0.5nm)(1M/1 X 109nm) = 5 X 10-10M
Remember that we treat units just as we do numbers. The only way to get meters squared is to divide:
2 X 10-4M3/5 X 10-10M = 4 X 105 M3-1 = 400000M2
45.
a. C = (162 – 32)/1.8 = 72.2C
b. 0.0F = -17.8C, K = -17.8 + 273 = 255 and to one sig fig the answer is 300K
c. F = 1.8(-18) + 32 = -0.40F
d. 212 = 273 + C, C = 212 – 273 = -61.0
47.
F = 1.8C + 32. This is a single equation with 2 unknowns, the F and C. However, this question says they
are equal, so F = C, and we can call them both X.
X = 1.8X + 32. Subtract 1.8X from both sides to get, -0.8X = 32, and dividing both sides by -0.8x we find
that the answer is -40. When F = -40, C will also = -40, or when C = -40 so will F.
63.
4.0in = 1/3ft and 2.5ft X 1/3ft = 0.833ft2 the area of each line.
(15gal)(4qt/1gal)(43ft2/1qt)(1dashed line/0.833ft2) = 3100 dashed lines
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65.
(2 X 104L/day)(1000cm3/1L)(1M3/1 X 106cm3)(180µg Hg/1M3) = about 4000µg Hg/day. Can you say Hg
Poisoning boys and girls!
83.
(695g)(12oz/373g)(480gr/1oz)(1scruple/20gr) = 537 scruples
86.
125.934g = the mass of everything. From this we subtract the mass of the metal and cylinder to get:
125.934 – 15.454 – 89.450 = 21.030g, which is the mass of the liquid.
Density of liquid = 21.030g/25.0ml = 0.841g/ml
Density of metal = 15.454g/5.7ml = 2.7g/ml