Logarithm - Problems


1. Find the logarithms of the following numbers:

a. 8.16

b. 1.652

c. 0.004918

d. 1.0 x 10-6

e. 4.5 x 10-10

2. Find the numbers whose logarithms are

a. 0.8831

b. 1.743

c. -3.161

d. -6.918

e. -126

3. Calculate the value of y in each case:

a. y 5 -6.14 x 100 x log 0.0360

b.

c. -1.614 5 (300y) log (2.0 x 103)

4. Calculate y in each case:

a.

b.

c.

5. Find the value of log y if

a. y 5 1.6 x 10-4

b. y 2 5 1.6 x 10-4

c. y1/2 5 1.6 x 10-4

6. Express in terms of log x and log y:

a. log x/y b. log xy c. log xy2

7. Given that

x 5 y 2/z1/2

obtain a relation between log x, log y, and log z.

8. Consider the equation

y 5 12.4 - 2.0 log x 8/5

a. What is y when x 5 3.0?

b. What is x when y 5 1.0?

9. Find the natural logarithms of

a. 6.023 b. (2.718)2

c. 6.18 x 10-5

10. Find the value of

a. e1.00

b. e-2.50

c. e12.92

11. Calculate the pH of solutions which have the following concentrations of H+:

a. 1.0 x 10-6

b. 2.61 x 10-2

c. 3.0 x 10-9

d. 6.0

12. Calculate the concentration of H+ in solutions with the following pH:

a. 4.0

b. 12.60

c. 3.14

d. -1.0

13. In a water solution saturated with H2S;

(conc. H+)2 x (conc. S2-) 5 1 x 10-21

What is the concentration of S2- in a solution of this type which has a pH of 4.0?

14. In any water solution at 258C;

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

Show, using this equation, that

pH 1 pOH 5 14.00

where pOH 5 -log (conc. OH-).

15. For a water solution of acetic acid, the following relation holds:


where Ka is the ionization constant of acetic acid, HAc. Starting with this equation, obtain a relation between log Ka, pH, and log (conc. HAc).

16. In a certain electrical cell, the voltage, E, is given by the expression


a. Write an equation relating E to pH.

b. Calculate E when pH 5 3.0.

c. Calculate pH when E 5 0.50 V.

17. The fraction, f, of molecules with energy equal to or greater than the activation energy, Ea, is given by the equation

What is f when Ea 5 1.00 x 104J, T 5 298 K, R 5 8.31 J/K?


Answers - Logarithms

Return to Math Review Index
aticalPi 1">5 8.31 J/K?


Answers - Logarithms

Return to Math Review Index