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Find the pH for a solution of Ca(OH)2 with a molarity of 1.0 x 10-4.
Answer
[H+][OH–] = 1.0 x 10-14
[H+][2(1.0 x 10-4] = 1.0 x 10-14
[H+] = 5.0 x 10-11
pH = -log [H+]
pH = -log [5.0 x 10-11]
pH = 10
The letters “pH” represent the French words “pouvoir hydrogene” which means “hydrogen power”.
The definition of pH is pH is equal to the negative log (logarithm) of the _________ ion concentration of a solution.
Answer
hydrogen
The logarithm of a number is the power to which 10 must be raised to equal that number.
A pH value of less than 7 indicates a(n) ____________ solution.
Answer
acidic
A pH value of ________ indicates a neutral solution.
Answer
7
A pH value of more than 7 indicates a(n) _______________ solution.
Answer
basic
The greater the [H+] concentration, the ________ the pH.
Answer
lower
If a solution is _______________ the [H+] concentration equals the [OH–] concentration.
Answer
neutral
An aqueous base has a pH of 8.1. Another has a pH of 10. Which solution has the larger concentration of [OH–] ions?
a. The solution with a pH of 10 has a larger concentration of [OH–] ions.
b. The solution with a pH of 8.1 has a larger concentration of [OH–] ions.
Answer
A.
Determine the pH of a 0.035M H2SO4 solution.
Answer
pH = -log [H+] = -log [2(3.5 x 10-2] = -(-1.2) = 1.2
The pH of a 0.010M Mg(OH)2 solution is ______.
Answer
[H+][OH–] = 1.0 x 10-14
[H+][2(1.0 x 10-2)] = 1.0 x 10-14
[H+] = 5.0 x 10-13
pH = -log [H+] = -log [5.0 x 10-13] = -(-12.3)
pH = 12
What is the hydrogen ion concentration of an aqueous HCl solution that has a pH of 3.0?
Answer
pH = -log [H+
3.0 = -log [H+]
[H+] = 1.0 x 10-3 M
What is the hydroxide ion concentration of this same solution?
Answer
[H+][OH–] = 1.0 x 10-14
[1.0 x 10-3][OH–] = 1.0 x 10-14
[OH–] = 1.0 x 10-11 M
Which ion, H+ or OH–, is in greater concentration?
Answer
H+
(1.0 x 10-3 is greater than 1.0 x 10-11)
Is this solution acidic or basic?
Answer
Acidic