Problems - Exponential (Scientific) Notation


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1. Express the following numbers in exponential notation:

a. 1000

b. one billion

c. 0.000 001

d. 16,220

e. 212.6

f. 0.189

g. 6.18

h. 0.000 000 078 46

2. Express as ordinary numbers:

a. 1.2 x 10-3

b. 6.4 x 101

c. 3.0 x 100

d. 4.1 x 105

e. 1.4 x 10-6

3. In each of the following pairs, select the number which is larger:

a. 3 x 103 ; 3 x 10-3

b. 3 x 103 ; 10,000

c. 0.0001; 2 x 10-4

d. 6 x 107 ; 4 x 108

e. 9.6 x 10-3 ; 1.5 x 10-2

f. 21 x 103; 2.1 x 104

4. Arrange the following numbers in increasing order, starting with the smallest:

2.0 x 10-5, 4.6 x 103, 3.6 x 10-1, 7.1 x 10-5, 6.0 x 10-2

5. Carry out the indicated operations, citing answers in standard exponential notation:

a. (6.20 x 104) x (1.50 x 108)

b. (4.2 x 10-3) x (1.50 x 108)

c. (3.62 x 104) x (2.91 x 10-7)

d. (8.16 x 10-4) x (4.78 x 1019)

e. (1.39 x 107)/(1.10 x 104)

6. Carry out the indicated operations:

a. (3.48 x 103) / (6.72 x 105)

b. (7.2 x 10-3)/(3.6 x 10-4)

c. (2.60 x 104)/(7.70 x 10-12)

d.

7. Evaluate

a. (2.16 x 10-3)2

b. (4.9 x 104)3

c. (6.0 x 10-21)2

d. (9.0 x 106)1/2

e. (8.4 x 105)1/2

8. Find the value of

a. (6.2 x 10-2)1/2

b. (1.62 x 10-7)1/2

c. (2.14 x 1010)1/3

d. (6.0 x 104)2 x (3.0 x 10-7)1/2

e. (3.0 x 107)1/5

9. Carry out the indicated operations:

a. 3.02 x 104 + 1.69 x 104

b. 6.10 x 104 + 1.0 x 103

c. 8.17 x 105 - 1.20 x 104

d. 9.68 x 104 + 7.01 x 102

10. Find the value of

a. 4.18 x 10-2 + 1.29 x 10-2

b. 5.9 x 10-5 + 1.86 x 10-4

c. 6.49 x 10-10 - 1.23 x 10-11

d. 6.02 x 10-23 - 1.0 x 102

11. A helium atom has the following properties:

Mass = 0.000 000 000 000 000 000 000 006 65 g

radius = 0.000 000 004 6 cm

average speed at 25_ C = 136,000 cm/s

Express these quantities in standard exponential notation.

12. Complete the following table, giving the solubilities of several different compounds as ordinary numbers (first column) or exponential numbers (second column).

AgCl _______ =1.3 x 10-5

PbCl2 0.016 = _______

AgC2H3O2 0.045 = _______

13. Three different reactions have the following rates:

Reaction A: 2.4 x 10-4 moles per liter per second

Reaction B: 3.6 x 10-4 moles per liter per second

Reaction C: 6.5 x 10-5 moles per liter per second

Which of these reactions is the fastest? the slowest?

14. The solubility products (Ksp) of several ionic compounds are listed below. Arrange these compounds in order of increasing Ksp.

Compound Ksp

Al(OH)3 5 x 10-33

Cr(OH)3 1 x 10-30

Fe(OH)2 1 x 10-13

Fe(OH)3 5 x 10-38

Mg(OH)2 1 x 10-11

15. The masses of atoms of four different elements are listed below. In each case, calculate the mass of 6.022 x 1023 atoms (one mole):

He 6.647 x 10-24 g

N 2.325 x 10-23 g

Sr 1.455 x 10-22 g

Which of these atoms is the heaviest? the lightest?

16. In water at 25_ C, the concentrations of H+ and OH- are related by the equation

(conc. H+) x (conc. OH-) 5 1.0 x 10-14

Using this relation, complete the table below:

conc. H+ conc. H-

______ 2.5 x 10-4 ______

3.6 x 10-8 ______ ______

______ ______ 102

17. According to the Bohr theory of the H atom, the orbital radius is given by


where r is the radius in centimeters, h = 6.6 x 10-27, e = 4.8 x 10-10, m = 9.1 x 10-28, p = 3.14, and n is the so­called quantum number which can have any integral positive value. Calculate r when n = 1; n = 2; n = 3.

18. When hypochlorous acid, HOCl, is dissolved in water, the following relation exists:

(conc. H+)2 = (3.2 x 10-8) x (conc. HOCl)

Complete the following table:

conc. HOCl conc. H+

1.0 ______ ______

0.10 ______ ______

0.010 ______ ______

19. Dalton's Law tells us that the total pressure of a mixture of hydrogen and helium is the sum of the partial pressures of the two gases. If the total pressure is 1.224 x 103 mm Hg and the partial pressure of helium is 9.80 x 102 mm Hg, what is the partial pressure of hydrogen?

20. A certain reaction is carried out in a bomb calorimeter. Part of the heat evolved in the reaction is absorbed by the water, part by the bomb. If the water absorbs 12.02 kJ and the bomb absorbs 650 J, what is the total amount of heat evolved? (1 kJ = 103 J)


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e heat evolved in the reaction is absorbed by the water, part by the bomb. If the water absorbs 12.02 kJ and the bomb absorbs 650 J, what is the total amount of heat evolved? (1 kJ = 103 J)


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