2. Acid and Base Strength

3. Acids Have a sour taste.

4. Acids Turn blue litmus red. Turn methyl orange red.

5. Acids Will react with: some metals to produce a salt and H 2. metal oxides to produce a salt and H 2 O. metal carbonates to produce a salt, H 2 O, and CO 2. bases to produce a salt and H 2 O. Mg + 2HCl  MgCl 2 + H 2 MgO + 2HCl  MgCl 2 + H 2 O MgCO 3 + 2HCl  MgCl 2 + H 2 O + CO 2 Mg(OH) 2 + 2HCl  MgCl 2 + 2H 2 O

6. Acids Are electrolytes. Conduct an electric current when dissolved.

7. Bases Have a bitter taste. Coffee itself is acidic, but it contains an alkaline compound – caffeine – which contributes to its bitter taste.

8. Bases Feel slimy or slippery to the touch.

9. Bases Turn red litmus blue. Turn methyl orange yellow. Turn phenolphthalein pink. Litmus pH scale.

10. Bases React with acids to produce salt and H 2 O. HCl + NaOH  NaCl + H 2 O

11. Bases Are electrolytes.

12. Review Properties of Acids ◦Taste sour. ◦Turn litmus red. ◦Proton (H + ) donors. ◦Inc. [H 3 O + ] in aqueous solutions. Properties of Bases ◦Taste bitter. ◦Turn litmus blue. ◦Proton acceptors. ◦Inc. [OH - ] in aqueous solutions.

13. Review pH Scale ◦Traditionally 0 - 14.  Can have pH 14. ◦pH < 7  Acidic solution. ◦pH = 7  Neutral solution. ◦pH > 7  Basic solution.

14. pH Scale AcidicBasic 01234567891011121314 pH Scale

15. HCl, A Strong Acid

16. HF, A Weak Acid

17. As [H + ] Increases, [OH -1 ] Decreases 1x10 -13 M 1x10 -12 M 1x10 -11 M 1x10 -10 M 1x10 -9 M 1x10 -8 M 1x10 -7 M 1x10 -6 M 1x10 -5 M 1x10 -4 M 1x10 -3 M 1x10 -2 M 1x10 -1 M 1x10 -13 M 1x10 -12 M 1x10 -11 M 1x10 -10 M 1x10 -9 M 1x10 -8 M 1x10 -7 M 1x10 -6 M 1x10 -5 M 1x10 -4 M 1x10 -3 M 1x10 -2 M 1x10 -1 M [H + ] [OH -1 ] Neutral Solution Acid added to neutral solution Base added to neutral solution

18.  In any aqueous solution: ◦ [H + ] [OH -1 ] = 1x10 -14 ◦ As [H + ] goes up, [OH -1 ] must decrease. ◦ As [OH -1 ] goes up, [H + ] must decrease.  In other words, adding an acid to water causes the solution to become more acidic and less basic.  Adding a base to water causes the solution to become less acidic and more basic.

19.  If [H + ] = 1x10 -3 M, what is [OH -1 ]? ◦ [H + ][OH -1 ] = 1x10 -14 ◦ (1x10 -3 M)[OH -1 ] = 1x10 -14 ◦ [OH -1 ] = (1x10 -14 ) / (1x10 -3 ) ◦ [OH -1 ] = 1x10 -11 M  If [OH -1 ] = 1x10 -8 M, what is [H + ]? ◦ [H + ][OH -1 ] = 1x10 -14 ◦ [H + ](1x10 -8 M) = 1x10 -14 ◦ [H + ] = (1x10 -14 ) / (1x10 -8 M) ◦ [H + ] = 1x10 -6 M

20.  pH = power of Hydrogen ◦ negative logarithmic (powers of ten) scale.  pH = -log 10 [H + ] ◦ If [H + ] = 1x10 -1 M,  pH = -log(1x10 -1 M) = 1 ◦ If [H + ] = 1x10 -2 M,  pH = -log(1x10 -2 M) = 2 ◦ If [H + ] = 1x10 -3 M,  pH = -log(1x10 -3 M) = 3

21.  The logarithm of a number is the power to which you would have to raise a base to equal that number. ◦ Unless otherwise indicated, assume the base is 10.  log(100) = 2 ◦ because 10 2 = 100  log(1000) = 3 ◦ because 10 3 = 1000  log(0.001) = -3 ◦ because 10 -3 = 0.001  log(0.000 001) = -6 ◦ because 10 -6 = 0.000 001

22. [H 3 O +1 ] [OH -1 ]

23. Calculations Involving pH, pOH, [H+], and [OH-] of strong Acids and Bases pH = -log [H + ] pOH = -log [OH - ] pOH + pH = 14

24.  What are the pH values of the following solutions? ◦ 1x10 -1 M H +  pH = -log(1x10 -1 M) = 1 ◦ 1x10 -3 M H +  pH = -log(1x10 -3 M) = 3 ◦ 1x10 -5 M H +  pH = -log(1x10 -5 M) = 5 ◦ 1x10 -1 M OH -1  [H + ] = (1x10 -14 ) / (1x10 -1 M) = 1x10 -13 M  pH = -log(1x10 -13 M) = 13