1. The pH concept  [H + ] is cumbersome so the pH scale was created.  pH is the negative logarithm of the hydrogen-ion concentration.  pH = -log[H + ]  [H + ] is cumbersome so the pH scale was created.  pH is the negative logarithm of the hydrogen-ion concentration.  pH = -log[H + ]

2. Sample pH problems 1 of 3  The hydrogen-ion concentration of a solution is 2.7 x 10 -10 mol/L. What is the pH of the solution.  Answer  pH = -log[2.7 x 10 -10 ]  pH = 9.6  The hydrogen-ion concentration of a solution is 2.7 x 10 -10 mol/L. What is the pH of the solution.  Answer  pH = -log[2.7 x 10 -10 ]  pH = 9.6

3. Sample pH problems 2 of 3  The pH of a solution is 6.8. What is the [H + ]?  Answer  6.8 = -log [H + ]  -6.8 = log [H + ]  10 x (-6.8) = log [H + ] 10 x  1.6 x 10 -7 mol/L = [H + ]  The pH of a solution is 6.8. What is the [H + ]?  Answer  6.8 = -log [H + ]  -6.8 = log [H + ]  10 x (-6.8) = log [H + ] 10 x  1.6 x 10 -7 mol/L = [H + ]

4. Sample pH problems 3 of 3  What is the pH of a solution if the [OH - ] = 4.0 x 10 -11 mol/L  Answer  [H + ] x 4.0 x 10 -11 mol/L = 1.0 x 10 -14 M 2  [H + ] = 2.5 x 10 -4 mol/L  pH = -log(2.5 x 10 -4 mol/L)  pH = 3.6  What is the pH of a solution if the [OH - ] = 4.0 x 10 -11 mol/L  Answer  [H + ] x 4.0 x 10 -11 mol/L = 1.0 x 10 -14 M 2  [H + ] = 2.5 x 10 -4 mol/L  pH = -log(2.5 x 10 -4 mol/L)  pH = 3.6