1. Net Ionic Equations HCl(aq) + NaOH(aq)  NaCl(aq) + H 2 O(l) What really happens: H + (aq) + OH - (aq)  H 2 O(l) Sodium ion and chloride ion are “spectator ions”

2. Reactions involving weak bases HCl(aq) + NH 3 (aq)  NH 4 + (aq) + Cl - (aq) Net-Ionic Equation:

3. What are the products: CH 3 CO 2 H(aq) + NaOH(aq)  1. CH 3 CO 2 H 2 + (aq) + NaO(aq) 2. CH 3 CO 2 - (aq) + H 2 O(l) + Na + (aq) 3. CH 4 (g) + CO 2 (g) + H 2 O(l) Net-Ionic Equation:

4. What are the products: HCN(aq) + NH 3 (aq)  1. NH 4 + (aq) + CN - (aq) 2. H 2 CN + (aq) + NH 2 - (aq) 3. C 2 N 2 (s) + 3 H 2 (g) Net-ionic equation:

5. Solution Concentration: Molarity Molarity = moles solute per liter of solution 0.30 mol NH 3 dissolved in 0.500 L Concentration = Written like: [NH 3 ] = 0.60 M If you dissolve 0.32 mol NH 3 to make 750 mL of solution, what is [NH 3 ]?

6. pH: Quantitative Measure of Acidity Acidity is related to concentration of H + (or H 3 O + ) pH = -log[H + ][H + ] = 10 -pH

7. pH Scale In pure water, a few molecules ionize to form H 3 O + and OH – H 2 O + H 2 O  OH – + H 3 O + In acidic and basic solutions, these concentrations are not equal acidic: [H 3 O + ] > [OH – ] basic: [OH – ] > [H 3 O + ] neutral: [H 3 O + ] = [OH – ]

8. pH Scale Measure how much H 3 O + is in a solution using pH pH < 7.0 = acidic pH > 7.0 = basic pH = 7.0 = neutral Measure of H 3 O + and OH – concentration (moles per liter) in a solution As acidity increases, pH ?

9. pH Scale The pH scale is logarithmic: 10010 2 log(10 2 ) = 2 1010 1 log(10 1 ) = 1 110 0 log(10 0 ) = 0 0.110 –1 log(10 –1 ) = –1 0.0110 –2 log(10 –2 ) = –2 pH = –log [H + ]

10. pH Scale pH = –log [H 3 O + ] What is the pH if [H + ] = 1 x 10 –5 ? Acidic or basic? What is the pH if [H + ] = 1 x 10 –9 ? Acidic or basic? What is the pH if [H + ] = 0.000057 M?

11. pH of Strong Acid Solutions For monoprotic strong acids: [H + ] = [acid] What is the pH of a 2.4 x 10 -2 M solution of HNO 3 ?

12. [H 3 O + ] from pH Finding [H 3 O + ] from pH [H + ] = 10 -pH What is [H + ] if pH = 8.9?

13. What is the possible range of pH values?