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Question: 1. Which answer is a true statement about pH values? a. A high pH value corresponds to a high H+ ...

1. Which answer is a true statement about pH values?

a. A high pH value corresponds to a high H+ concentration

b. Stomach acid has a high pH value.

c. none of the above.

d. Pure water has a pH value of 0.

e. pH is important in life mainly because it effects many everyday applications.

2. The industrial smoke from factories has led to acid rain,which has lowered the pH of a number of lakes having a pH of approximately 5.0. What is the hydronium ion concentration of these lakes ?

a. 5.0 M

b. 10-5 M

c. 105 M

d. log 5.0 M

e. 5.0 %

  

3. A fish tank containing a number of exotic fish needs a pH of 5.0 , an indicator indicates the pH of the tank is 7.0. What should be done to the hydrogen ion concentration to set the tank to the correct pH.

a. cut it in half.

b. reduce it to 1/100 of its present value.

c. double it.

d. raise it 200 times its present value.

e. raise it 100 times its present value.

4. At 25^oC, a sample of milk of magnesia, used as an antacid, has a pH of 10.50. What is the [OH-] in this solution?

a. 3.2 x 10-11 M

b. 2.8 x 10-5 M

c. 3.2 x 103 M

d. 3.0 x 10-2 M

e. 3.2 x 10-4 M

5. A sample of blood at 25oC has a pH of 7.34. What is the [H3O+] in this solution?

a 4.6 x 10-8 M

b. 6.5 x 10-4 M

c. 2.2 x 109 M

d. 8.7 x 10-1 M

e. 4.6 M

6. An aqueous solution at 25oC has [OH-] = 1.0 x 10-5 M. What is the pH of this solution?

a. 5.00

b. 3.00

c. 2.00

d. 9.00

e. 4.70

7. An aqueous solution at 25oC has [OH-] = 5.0 x 10-10 M. What is the pH of this solution?

a. 10.00

b. 4.70

c. 5.00

d. 9.30

c. 0.70

8. An aqueous solution at 25oC has [H+] = 5.0 x 10-10 M. What is the pH of this solution?

a. 9.30

b. 0.70

c. 5.00

d. 4.70

e. 10.00

9. The pH values of five solutions are given below. Which is the most alkaline?

a. pH = 4.5

b. pH = 13.0

c. pH = 0.0

d. pH = 1.0

e. pH = 7.0

10. Which of the following solutions is basic?

i. [H3O+] = 2 x 10-8 M

ii. [OH-] = 2 x 10-6 M

iii. [H3O+] = 9 x 10-6 M

a. i , ii, and iii

b. iii

c. ii

d. i and ii

Answer 1

1) e) pH is important in life mainly because it effects many every day applications

2) b) 10^-M

pH = - log [H3O+]

-log[H3O+] = 5

[ H3O+ ] = 10^-5M

3) e) raise it 100 time its present value

4) e) 3.2×10^-4M

pH= 10.50

pH + pOH = 14

10.50 + pOH = 14

pOH = 14 - 10.50 = 3.50

pOH = -log[OH-]

-log[OH-] = 3.50

[ OH- ] = 3.2×10^-4M

5) a) 4.6 ×10^-8M

6) d)9.00

7) b) 4.70

8) a) 9.30

9) b) pH = 13.0

pH = 7 neutral

pH > 7 alkaline/basic

pH< 7 acidic

10) a) i , ii and iii