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Lowell High School Chemistry

pH and pOH Online Question Set

1.       For each pair of concentrations, tell which represents the more acidic solution.

a. [H+] = 1.2 x 10-3 M or [H+] = 4.5 x 10-4 M

b. [H+] = 2.6 x 10-6 M or [H+] = 4.3 x 10-8 M

c. [H+] = 0.000010 M or [H+] = 0.0000010 M

2.       For each pair of concentrations, tell which represents the more basic solution.

a. [H+] = 1.59 x 10-7 M or [H+] = 1.04 x 10-8 M

b. [H+] = 5.69 x 10-8 M or [OH] = 4.49 x 10-6 M

c. [H+] = 5.99 x 10-8 M or [OH] = 6.01 x 10-7 M

3.       Why do scientists tend to express the acidity of a solution in terms of its pH, rather than in terms of the molarity of hydrogen ion present?

4.       Calculate the pH according to the molarity of the solution given below. Tell whether each solution is acidic, basic, or neutral.

a. 1.33 x 10-1 M Al(OH)3

b. 5.35 x 10-2 M HNO3

5.       Calculate the hydrogen ion concentration, in moles per liter, for solutions with each of the following pH values.

a. pH = 1.04

b. pH = 5.99

6.       If [H+] = 4.29 x 10-11 M, calculate the hydroxide ion concentration and the pH and pOH of the solution.

7.       Calculate the pH and pOH of the following weak acids or bases, given their molarity and their Ka or Kb constants.

a. 0.464 M acrylic acid, HC3H3O2 (Ka = 5.5 x 10-5)

b. 0.224 M phenol, HOC6H5 (Ka = 1.0 x 10-10)

c. 0.123 M pyridine, C5H5N (Kb = 1.5 x 10-9)

d. 0.079 M quinoline, C9H7N (Kb = 6.3 x 10-10)

Save Question #7 for after Spring Break. No need to do. Just do #1-6 for now.

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