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Practice Problems 1
Chapter 1
CHE 151
Graham/08
Exponential Notation, Significant Figures and Rounding
1.
Write each number in scientific (exponential) notation and then indicate the number
of significant figures.
Scientific Notation
2.
# of Sig.Fig.
a)
9624
__9.624 x 103_________
____4_______
b)
620.0
__6.200 x 102_________
____4_______
c)
0.00892
__8.92 x 10-3_________
____3_______
d)
5.990 x 104
e)
0.82
__8.2 x 10-1_________
____2_______
f)
500.060
__5.00060 x 102______
____6_______
g)
4.82 x 10-4
h)
5000.0
__5.0000 x 103______
____5_______
i)
5000
__5 x 103__________
____1_______
xxxxxxxxxxxx
xxxxxxxxxxxx
____4_______
____3_______
Round each of the following to three significant figures, then rewrite the number in
scientific notation.
a)
25.67
=
25.7
2.57 x 101
b)
694.2
=
694
6.94 x 102
c)
0.056567
=
0.0566
5.66 x 10-2
d)
460500
=
461,000
4.61 x 105
e)
851.5 x 10-4 =
852 x 10-4
8.52 x 10-2
3.
Report the answer of the following calculations to the proper number of
significant figures. All numbers are measured quantities. Show your work.
a.
(427.932/396.5) - (0.07461/0.082967) =
1.079
0.8993 = 0.1797

____0.180________
b.
=
_____6.0_________
=
____0.510________
2.1 x 8.632 x 0.333

(2sf)
(3sf)

(5.018)
(10.2)
c.
(5.021 - 0.003) x (9.10 + 1.1)
(99.1 + 1.2)
(100.3)