13.
(E) (a) 8950. = 8.950 × 103 (4 sig. fig.)
(b) 10,700. = 1.0700 × 104 (5 sig. fig.)
(d)
14.
19.
20.
21.
938.3 = 9.383 × 102
(E) (a) 3.21 × 10−2 = 0.0321
(c)
18.
0.0047 = 4.7 × 10−3 (e)
(c) 0.0240 = 2.40 × 10−2
121.9 × 10−5 = 0.001219
(f)
275,482 = 2.75482 × 105
(b)
5.08 × 10−4 = 0.000508
(d)
16.2 × 10−2 = 0.162
(E) (a) The number of pages in the text is determined by counting; the result is an exact
number.
(b)
An exact number. Although the number of days can vary from one month to another
(say, from January to February), the month of January always has 31 days.
(c)
Measured quantity: The area is determined by calculations based on measurements.
These measurements are subject to error.
(d)
Measured quantity: Average internuclear distance for adjacent atoms in a gold medal
is an estimated value derived from X-ray diffraction data, which contain some
inherent error.
(E) Each of the following is expressed to four significant figures.
(a)
3984.6 ≈ 3985
(b) 422.04 ≈ 422.0
(d)
33,900 ≈ 3.390 × 104 (e) 6.321 × 104 is correct
(c) 186,000 = 1.860 × 105
(f) 5.0472 × 10−4 ≈ 5.047 × 10−4
(E) (a) 450 has two or three significant figures; trailing zeros left of the decimal are
indeterminate, if no decimal point is present.
(b)
98.6 has three significant figures; non-zero digits are significant.
(c)
0.0033 has two significant digits; leading zeros are not significant.
(d)
902.10 has five significant digits; trailing zeros to the right of the decimal point are
significant, as are zeros flanked by non-zero digits.
(e)
0.02173 has four significant digits; leading zeros are not significant.
(f)
7000 can have anywhere from one to four significant figures; trailing zeros left of the
decimal are indeterminate, if no decimal point is shown.
(g)
7.02 has three significant figures; zeros flanked by non-zero digits are significant.
(h)
67,000,000 can have anywhere from two to eight significant figures; there is no way
to determine which, if any, of the zeros are significant, without the presence of a
decimal point.
(E) (a) 0.406 × 0.0023 = 9.3 × 10−4
(c)
(b)
0.1357 × 16.80 × 0.096 = 2.2 × 10−1
0.458 + 0.12 − 0.037 = 5.4 × 10−1 (d)
32.18 + 0.055 − 1.652 = 3.058 × 101
1
Chapter 1: Matter – Its Properties and Measurement
29.
(E) (a) 68.4 in.×
(c)
1.42 lb ×
(e)
1.85 gal×
2.54 cm
= 174 cm
1 in.
453.6 g
= 644 g
1 lb
4 qt
1 gal
×
0.9464 dm
1 qt
12 in. 2.54 cm
1m
×
×
= 29 m
1 ft
1 in.
100 cm
(b)
94 ft ×
(d)
248 lb ×
0.4536 kg
= 112 kg
1 lb
3.72 qt ×
0.9464 L 1000 mL
×
= 3.52 ×103 mL
1 qt
1L
3
3
=7.00 dm (f)
2
30.
⎛ 1000 m ⎞
6
2
(M) (a) 1.00 km 2 × ⎜
⎟ = 1.00 × 10 m
⎝ 1 km ⎠
3
(b)
⎛ 100 cm ⎞
6
3
1.00 m × ⎜
⎟ = 1.00 × 10 cm
1
m
⎝
⎠
(c)
1 m ⎞
⎛ 5280 ft 12 in. 2.54 cm
6
2
1.00 mi 2 × ⎜
×
×
×
⎟ = 2.59 × 10 m
1 ft
1 in.
100 cm ⎠
⎝ 1 mi
3
2
41.
(E)
o
o
low: oF = 59o CF (oC) +32 oF = 59o CF −10 oC +32 oF =14 oF
o
o
(
)
(50 C) +32
high: oF = 59o CF (oC) +32 oF = 59o CF
50.
o
o
F =122 oF
(M) Density is a conversion factor.
volume = ( 283.2 g filled !121.3 g empty) "
2
1 mL
= 102 mL
1.59 g