1. pH Scale 2-27-12 Standard: 5d-students know how to use the pH scale to characterize acid and base solutions

2. The pH Scale The pH of a solution is a measure of its hydronium ion concentration.

3. The pH scale is a number scale from 0 to 14 to describe the concentration of hydronium ions in a solution. A pH of 7 indicates a neutral solution. Acids have a pH less than 7. Bases have a pH greater than 7.

5. If you add an acid to water, the concentration of H 3 O + increases and the concentration of OH - decreases. The lower the pH value, the greater the H 3 O + ion concentration in solution is.

6. If you add a base to water, the concentration of OH - increases and the concentration of H 3 O + decreases. The higher the pH value, the lower the H 3 O + ion concentration is.

7. Example Substance A has a pH of 3. Substance B has a pH of 10. Is the substance A considered acidic or basic? Is substance B considered acidic of basic? From this does this mean there are more hydronium ions present or hydroxide ions present for substance A? Substance B? From Friday does this mean your substances are weak or strong acids or bases?

8. Try it on your own Substance A has a pH of 5, Substance B has a pH of 9. Is substance A and B considered acidic of basic? From this does this mean there are more hydronium ions present or hydroxide ions present for substance A? Substance B? Are substance A and B weak or strong acids or bases?

9. Exit Question a) What does the pH scale measure? Given the following pH numbers is the sample a base, acid, or neutral? A) 6 B) 12 C) 7 Please include a reflection on how you feel about your activity today.