Page 40 - Theory and Problems of BEGINNING CHEMISTRY

CHAP. 2] MATHEMATICAL METHODS IN CHEMISTRY 29

2.36. Perform the following calculations:

−4
10
4
(a) (2.20 × 10 )(3.50 × 10 ) (e) (2.20 × 10 −10 )/(3.50 × 10 )
4
10
−4
(b) (2.20 × 10 ) + (3.50 × 10 ) (f) (2.20 × 10 −10 ) − (3.50 × 10 )
19
21
4
10
(c) (2.20 × 10 )/(3.50 × 10 ) (g) (2.20 × 10 ) + (3.5 × 10 )
10
10
4
(d) (2.20 × 10 −10 )/(3.50 × 10 ) (h) (2.20 × 10 )(3.50 × 10 )
Ans. (a)7.70 × 10 14 (c) 6.29 × 10 5 (e) 6.29 × 10 −7 (g)2.24 × 10 21
(b)2.20 × 10 10 (d)6.29 × 10 −15 (f) −3.50 × 10 −4 (h)7.70 × 10 20
−2
0
2
2.37. Convert the following numbers to decimal form: (a)5.6 × 10 ,(b)7.07 × 10 , and (c)6.11 × 10 .
Ans. (a) 560 (b) 0.0707 (c) 6.11
2.38. Perform the following calculations:
23
6
(a)1.70 × 10 + 9.7 × 10 5 (d)6.02 × 10 − 1.3 × 10 22
(b)1.11 × 10 −10 + 4.28 × 10 −9 (e)1.40 × 10 −11 − 2.30 × 10 −9
3
(c)7.7 × 10 + 4.05 × 10 3
Ans. (a)2.67 × 10 6
(b)4.39 × 10 −9
(c)1.18 × 10 4
(d)5.89 × 10 23
(e) −2.29 × 10 −9
2.39. Perform the following calculations:

8
7
(a) (4.30 × 10 )(1.60 × 10 ) (d) (1.65 × 10 −19 )/(1.10 × 10 −22 )
−1
−3
22
23
(b) (3.45 × 10 )(2.00 × 10 ) (e) (6.02 × 10 )/(6.02 × 10 )
1
4
(c) (4.13 × 10 )/(7.1 × 10 )
Ans. (a)6.88 × 10 15
(b)6.90 × 10 −4
(c)5.8 × 10 −4
(d)1.50 × 10 3
1
(e)1.00 × 10 = 10.0
2.40. Perform the following calculations:
−3
5
6
(a) (1.25 × 10 + 2.10 × 10 )/(3.11 × 10 )
4
3
−3
(b) (7.44 × 10 −4 + 2.46 × 10 )(6.16 × 10 + 2.5 × 10 )
9
9
8
(c) (7.7 × 10 + 2.3 × 10 ) − (2.7 × 10 )
21
23
22
(d) (6.02 × 10 + 2.0 × 10 ) + (4.20 × 10 )
−3
(e) (2.2 × 10 −9 + 1.1 × 10 −10 ) − (3 × 10 )
Ans. (a)4.69 × 10 8
(b)2.05 × 10 2
(c)9.7 × 10 9
(d)6.46 × 10 23
(e) −3 × 10 −3