1. Unit 15
Acids & Bases

2. Common Acids & Bases to Memorize
Hydrochloric Acid HCl
Sulfuric Acid H2SO4
Nitric Acid HNO3
Acetic Acid HC2H3O2
Bases
Sodium hydroxide NaOH
Calcium hydroxide Ca(OH)2
Ammonia NH3
or NH4OH
Potassium hydroxide KOH

3. Properties of Acids Taste sour React with metals to release H2 (g)
React with bases to form salts and water
Cause a color change in pH indicators (example : litmus turns red in acids)

4. Properties of Bases Taste bitter Feel slippery
React with acids to form salts and water
Cause a color change in pH indicators (example : turn litmus blue)

5. Arrhenius Theory of Acids & Bases Acids release H+1 example: HCl  H Cl-1 Bases release OH-1 example : NaOH  Na OH-1

6. Bronsted – Lowry Theory of Acids & Bases Acids donate a proton (H+1) example : HNO3  H NO3-1 Bases accept a proton example : NH3 + H+1  NH It is hard to see the base in the ammonia NH4OH  NH3 + H2O  NH OH-1

7. Phenolphthalein in acid is clear, in base is magenta (pink).
Indicators
pH indicators are chemicals which undergo a change in color when there is a change in the pH of a solution. Each pH indicator provides a color over a specific pH range.
Example:
Phenolphthalein in acid is clear,
in base is magenta (pink).

8. Useful pH ranges for several common indicators.

9. K = 1 equal amount of reactants and products
Two factors are involved in determining whether an acid or a base is strong or weak:
Original molarity
Example: M is very weak
0.1 M is much stronger
Equilibrium constant for the acid or base dissolving in water (the value of Kc)
K > 1000 mostly products
K = 1 equal amount of reactants and products
K < .001 mostly reactants

10. Strong Acids:. Sulfuric acid. Ka is very large
Strong Acids: Sulfuric acid Ka is very large H2SO4 (aq)  2 H+1(aq) + SO4-2(aq) Hydrochloric acid Ka is very large HCl (aq)  H+1(aq) + Cl-1(aq) Weak Acid: Acetic Acid Ka = 1.8 x HC2H3O2 (aq)  H+1(aq) + C2H3O2-1(aq)

11. Strong Bases. Sodium hydroxide. K is very large
Strong Bases Sodium hydroxide K is very large NaOH(aq)  Na+1(aq) + OH-1(aq) Weak Bases Ammonia Kb = 1.8 x NH4OH(aq)  NH4+1(aq) + OH-1(aq) Calcium hydroxide Kb = 1.3 x Ca(OH)2 (aq)  Ca+2 (aq) OH-1(aq)

12. Versions of formula MA VA = MB VB MA = (MB) (VB) VA MB = (MA) (VA) VB

13. A student uses 25 mL of M NaOH to titrate with 50 mL of HNO3 of unknown concentration. What is the concentration of the acid?

14. Microscopic picture of the solutions in the titration of unknown M HNO3 with M NaOH. (the problem on the 4th page back)
Phenolphthalein pH indicator added to flask

15. The pH curve for the titration of 50. 0 mL of unknown M HNO3 with 0
The pH curve for the titration of 50.0 mL of unknown M HNO3 with M NaOH.

16. Titration is a method used to determine the molarity of a solution
Titration is a method used to determine the molarity of a solution. A measured volume of the solution with unknown molarity is placed into a flask. A solution with known molarity is slowly poured into the solution until the neutralization point (end point) is reached. The point when : Acid + Base  H2O + salt Moles of Acid = Moles of Base MA VA = MB VB Remember : Moles = (Molarity) (volume in liters)

17. Titration Procedure 1. Label 4 beakers: acid, base, H2O, waste 2
Titration Procedure 1. Label 4 beakers: acid, base, H2O, waste 2. Place liquid of known concentration in the burette. A burette is a glass tube that delivers a varied amount of liquid with an accuracy of mL. Run some liquid out of the burette until the air bubbles are out of the tip of the burette Pipet 10 mL of unknown concentration solution into an Erlenmeyer flask. A pipet is a glass tube calibrated to deliver an exact amount of liquid. Accuracy is mL. Touch the last drop to the side of the flask Add a few drops of a pH indicator to the flask. Phenolphthalein is often used Run a rapid titration first to obtain a rough estimate of the amount of solution needed to reach the neutralization point. Be sure to record an initial reading and final reading of the solution in the burette. 6. Run 2 (or more) slow titrations to obtain accurate data to calculate the molarity of the unknown solution.

18. Titration of NaOH Titration Lab 1 Microscopic picture of the solutions in the titration of unknown M NaOH with a known M HCl.
Solution of HCl H+
Cl-
Phenolphthalein pH indicator added to flask
Solution of NaOH
Na+
OH-
M A VA = M B VB

19. MA VA = MB VB Rapid titration 1st Slow titration 2nd Slow titration
Final volume
Initial volume
Volume used
MA VA = MB VB

20. pH is a measure of the amount of acid in solution. It is defined as:
pH is a measure of the amount of acid in solution. It is defined as: pH = -log 10 [H+1] Any H2O solution must follow: H2O(L)  H+1(aq) + OH-1(aq) Kw = [H+1] [OH-1] = 1.0 x [H+1] = 1.0 x pH of pure H2O = -log10(1.0 x 10-7) = 7

21. The pH scale. A change from 1 pH unit to the next, the [H+1] changes by a factor of 10!

22. Calculate the pH of a solution that has the [H+1] of 0. 45 M
Calculate the pH of a solution that has the [H+1] of 0.45 M. Calculate the pH of a solution that has the [OH-1] of 0.31 M. Calculate the pH of a solution that is made with 0.84 g KOH mixed in 600 mL of H2O.

23. Calculating the pH is done using pH = -log10 [H+] If you know the pH, you can calculate the [H+] using 10-pH = [H+]
Calculate the [H+] if the pH = Calculate the Molarity of an HCl solution if the pH = Calculate the Molarity of a NaOH solution if the pH =12.55

24. pH data table [H+1] [OH-1] pH examples 1 x 100 1 x 10-14 Strong acid
Strong acid
1 x 10-1
1 x 10-13 1
1 x 10-2
1 x 10-12 2
Stomach acid
1 x 10-3
1 x 10-11 3
vinegar
1 x 10-4
1 x 10-10 4
tomato
1 x 10-5
1 x 10-9 5
coffee
1 x 10-6
1 x 10-8 6
1 x 10-7 7
Pure H2O 8
Sea H2O 9
Milk of magnesia 10 11
ammonia 12 13 14
Strong base

25. A titration was conducted using Acetic acid and Potassium hydroxide mL of acetic acid of .87 M was used to titrate 10 mL of potassium hydroxide. What is the molarity of the potassium hydroxide, and write the chemical equation for the reaction.

26. Introductory Lab for Acids & Bases
Look at how indicators work, color changes
Find the end point, where the amount of acid and base are equal. At this point, what is left is salt and water.
See activity series of metals. Some metals are more active than others.

27. Determination of M of Vinegar Titration Lab 2 Microscopic picture of the solutions in the titration of unknown M HC2H3O2 with a known M NaOH.
Solution of NaOH
Na+
OH-
Solution of HC2H3O2
Phenolphthalein pH indicator added to flask H+
C2H3O2-

28. Solid Acid Lab mole acid = mole base grams / molar mass = (M) (liters)
(molar mass)(grams) / molar mass = (M)(liters)(molar mass)
grams / (M)(liters) = (M) (liters) (molar mass) / (M)(liters)
grams / (M)(liters) = (molar mass)

29. Molar Mass of a solid acid Titration Lab #3 Microscopic picture of the solutions in the titration of unknown molar mass solid acid with a known M NaOH.
Solution of NaOH
Na+
OH-
Solution with solid acid
Phenolphthalein pH indicator added to flask
Ions from solid acid

30. Review Just memorize the 8 from your notes
Taste sour, release H+, donate protons, acid + base = salt + water,
Taste bitter, release OH-, accept protons, acid + base = salt + water
Hydrogen, H+1
Hydroxide, OH-1
Salt + water
HCl + NaOH  H2O + NaCl
HCl  H Cl if HCl is .1 M, then H+1 is also .1 M , -log .1 = pH of 1
NaOH  Na OH if NaOH is .01 M, then OH-1 is .01 M, you need to use the formula Kw = [H+1][OH-1] = 1 x x / .01 = 1 x which is the [H+1] log1x10-12 = pH of 12
0.78 M
Matching
1. K 5. M 9. F 13. N 17. L
2. O 6.. P 10. H 14. A 18. Q
3. J 7. D 11. E 15. B
4. G 8. R 12. I 16. C

31. Bases Crossword Down Across 2. Autoprotolysis 11. Atomic number 49
19. Normal
25. Amphiprotism
38. Methyl
Across
10. Alizarin
13. Nonmetals
20. Molality
24. Conjugate
27. Anhydrous
42. Equivalent

32. Acids Crossword Across 21. Yellow 30. Hydrogen 34. Hydronium
37. Oxidizing
Down
3. Corrosive
20. Dehydration
22. Oxyacids