1. Acids & Bases

2. Properties of Acids Example: HCl + H2O  Cl- + H3O+
Taste SOUR (ex: lemons, vinegar)
Corrosive to Metals
Produces H+ ions
Which is the same as H3O+ (hydronium ion)
Proton (H+) Donor
Example: HCl + H2O  Cl- + H3O+

3. Strong Acid vs Weak Acid
Strong Acid – an acid that completely dissociates to produce H+ ions in solution (lot of H+)
HCl, HNO3
Weak Acid – an acid that dissociates to a slight extent in aqueous solution (not that many H+)
HC2H3O2 (vinegar), lemon juice

4. Strong Acids vs. Weak Acids

5. Indicators
An indicator is a chemical that will change colors when placed in an acidic, basic or neutral environment
Indicator Colors for Acids
Litmus paper = red
Phenolphthalein = clear
Methyl orange = red

6. Properties of Bases Example: NH3 + H2O  NH4+ + OH -
Tastes Bitter (banana peel, dark chocolate, parsley)
Feels slippery (soap)
Produces OH- ions
Proton (H+) Acceptor
Example: NH H2O  NH4+ + OH -

7. Strong Bases v. Weak Bases
Strong Base – a base that completely dissociates to produce many OH- ions in solution
NaOH, KOH
Weak Base – a base that dissociates to a slight extent in aqueous solution (not that many OH-)
NH3 (ammonia)
Strength & Weaknesses of A & B Video

8. Indicators
Indicator Colors for Bases Litmus paper = blue Phenolphthalein = pink Methyl orange = yellow

9. Measuring the Amount of H+ and OH− Ions in a Solution
_____ Scale- measures the _____________ of [H+] ions in a solution
_____ Scale- measures the concentration of [ ____ ] ions in a solution
With the pH scale, we have another way to define acids and bases:
Acids have a pH _________7.0
Bases have a pH _________7.0
Neutral pH ___7.0 pH
concentration
pOH
OH−
below
Neutral
above =
Acidic
Basic

10. pH of different household items
Make predictions on whether a solution would be acidic, basic or neutral
Go around the room, checking each cup with pH paper (make sure used pH paper goes in GARBAGE!)
 to save pH paper, use HALF a side for each one.
Approximate pH colors:
purple-ish red (pH 2)
red (pH 4)
brown (pH 6)
Stays the same (pH 7)
green (pH 8)
blue (pH 10)

11. Examples of Common Acids
citrus
aspirin
Pepsi, _________ juices, ___________, stomach acid, battery acid, _____________, ______
vinegar
DNA

12. Examples of Common Bases
ammonia
Milk of magnesia, ___________, drain cleaner, soap, blood, ____________ tablets, ___________ ________.
antacid
baking soda

13. Acids & Bases pH video

14. Exit Slip
When using litmus paper, what color would it turn for an acid?
If something has a pH of 7, what is it considered?

15. Calculating pH and pOH

16. Strong Acids vs. Weak Acids

17. Strong Acids and Strong Bases
Since they ______________ disassociate…
…so when HCl is placed in water…
100 molecules of HCl are dissolved in water,
__________and __________ions are produced.
This comes into play for calculating the pH for strong solutions!
completely
100 H+ ions
100 Cl- ions

18. Measuring the Amount of H+ and OH− Ions in a Solution
_____ Scale- measures the _____________ of [H+] ions in a solution
_____ Scale- measures the concentration of [ ____ ] ions in a solution
Formulas
pH = − (log [H+]) pOH = −(log [OH−])
[H+] = 10−pH [OH−] = 10−pOH
pH + pOH = 14
With the pH scale, we have another way to define acids and bases:
Acids have a pH _________7.0
Bases have a pH _________7.0
Neutral pH ___7.0 pH
concentration
pOH
OH−
below
above =

19. [H+] = concentration of hydrogen ions 
_______________ (M)!
Molarity
Before we try calculating pH’s, watch video about background information on pH

20. pH = − (log [H+]) pOH = −(log [OH−])
Example of Calculating pH
a) Calculate the pH of a M HCl solution (so H+ ions)
b) What is the pOH of a solution with a pH of 3?
c) What is the concentration of [OH−] ions in the solution?
[H+] = M
pH = − (log M)
pH = 3
pH + pOH = 14
3+ pOH = 14
pOH = 11
[OH−] = 10−pOH
[OH−] = 10−11 M or 1 x 10−11 M
pH = − (log [H+]) pOH = −(log [OH−])
[H+] = 10−pH [OH−] = 10−pOH
pH + pOH = 14

21. pH = − (log [H+]) pOH = −(log [OH−])
You Try:
a) Calculate the pOH of a NaOH solution that has a pH of 8.50
b) What is the [OH−] of this solution?
c) What is the concentration of [H+] ions in the solution?
pH + pOH = 14
8.5 + pOH = 14
pOH = 5.5
[OH−] = 10−pOH
[OH−] = 10−5.5 M or 3.16 x 10−6 M
[H+] = 10−pH
[H+] = 10−8.5 M or 3.16 x 10−9 M
pH = − (log [H+]) pOH = −(log [OH−])
[H+] = 10−pH [OH−] = 10−pOH
pH + pOH = 14

22. pH = − (log [H+]) pOH = −(log [OH−])
Exit Slip
Which disassociates to more H+ ions: a strong acid or a weak acid? Calculate the pH of .005 M HCl solution Calculate the pOH of a solution with a pH of 6.
pH = − (log [H+]) pOH = −(log [OH−])
[H+] = 10−pH [OH−] = 10−pOH
pH + pOH = 14

23. Acid & Bases Intro to Calculations Answers
1) concentration 2) Concentration of Hydrogen (hydronium) Ions 3) Concentration of Hydrogen (hydronium) ions 1. a. –log(.005)  2.3 b. –log(2)  a. 5, A b. 12, B c. 7, N d. 10, A 3. a  b  1.26 x a. –log(.4)  b. –log(4)  *Calculating out a negative pH value does happen when concentrations are above 1.0 M (so for a very concentrated acid)

24. Recognizing A & B, Neutralization

25. Recognizing Acids & Bases
hydrogen
Acids start with the element: _______________
Bases generally have the polyatomic ion: _________________
Another common base: NH3 ammonia!
Hydroxide: OH-
Hydrogen: H+
hydroxide

26. Naming an Acid that is only 2 elements:
If the name of the anion (X) does not contain an oxygen,
 use prefix: hydro-
 and add suffix: –ic to the root name.
Example:
HCl
hydrochloric acid

27. Name the following: HF
LiOH

28. Name the following: HF
LiOH
Hydrofluoric acid
Lithium Hydroxide

29. Neutralization Reactions
Strong acid solutions contain:
Strong base solutions contians:
Neutralization reaction: an acid-base reaction that has initial concentrations and volume of reactants equal.
Equal H+ and OH-  NEUTRAL solution (pH = 7)
H+ ions
OH- ions

30. Neutralization Reactions
When an acid and base are mixed, the reaction produces _______
and ___________.
All neutralization reactions are ___________ replacement reactions.
Neutralization Reactions
salt
water
double
HX + M(OH)  ______ ______ MX
H2O
(“Salt”)

31. Neutralization (or Acid-Base Reaction)
Hydrochloric acid reacts with
Sodium hydroxide…
HCl (aq) + NaOH (aq)  _________ + __________
NaCl
H2O (l)
Salt
an ionic compound produced from a neutralization reaction
composed of equal amount of cations & anions
thus neutral
can be aqueous or depending on solubility may be a precipitate
Neutralization Video

32. Alka-Seltzer Activity
Each group needs: 1 small (150 or 250 mL) beaker, 1 alka-seltzer tablet, 1 pH paper
The Indicator is in the front table, add your 10 to 15 drops and then return it to the front!
Vinegar will be at the lab stations.
When you add 3 dropper fulls of vinegar!!
*When finished, you may pick up a study guide for the quiz on Wednesday! (will have class time tomorrow to work on the study guide).

33. Titration

34. Titration
A titration is a technique to determine the concentration of a solution (mixes acids and bases)
Known concentration is delivered by
a buret to an unknown concentration
and an indicator is used to determine
when neutralization has occurred.
The end point or the equivalence point
is the point of neutralization.
H+ ions = OH- ions

35. Determining the Concentration of an Acid (or Base) by Titration
MacidVacid = MbaseVbase
A 25 mL solution of HNO3 is neutralized by 18 mL of 1.0 M NaOH standard solution using phenolphthalein as an indicator. What is the concentration of the HNO3 solution?
( ) x ( ) = ( ) x ( )
Macid
25 mL
1.0 M
18 mL
Macid = M

36. Determining the Concentration of an Acid (or Base) by Titration
(Macid)(Vacid) = (Mbase)(Vbase)
You Try
How many mL of 2.0 M KOH will it take to neutralize 55 mL of a M HCl standard solution?
A 0.05 L solution of HNO3 is neutralized by L of 1.5 M NaOH standard solution using phenolphthalein as an indicator. What is the concentration of the HNO3 solution?

37. Exit Slip
How many mL of 1.5 M KOH will it take to neutralize 150 mL of a 0.75 M HCl standard solution? If you could be a strong acid, weak acid, strong base, weak base, giraffe, kangaroo or the moon, which would you be and why?

38. Answer Key Practice II
2. False – there is a small amount of H+, pH measures concentration of H ions. If you have a high pH there is a small, if you have a low pH there are more H+ ions 4. A, N, A, B, A, A, B, A, B, A 5)100 mL 6) 0.14 M 7) M 8) ) –log (.7) 11) 25 mL 12) Water and a salt

39. Answer Key to Acids
*  = indicates that it completely breaks apart into the ions (the arrows both ways, indicate that it does not)
2. Barium hydroxide (B) 3. (B) 4. Hydrosulfuric acid (A) 5. hydrobromic acid (A) 6. Hydronitric acid (A) 7 potassium hydroxide (B) 8. Hydrochloric acid (A) 9. lithium hydroxide (B) 13. NaOH 14. H3P 15. HF 16. Ca(OH)2 3rd Page: *DON’T Add HYDROS for the polyatomic ion ones! 1. Phosphoric acid 5. Hydrofluoric acid 6. Nitrous Acid
*Polyatomic ion for #1 is Phosphate  so –ic
*Polyatomic ion for #6 is Nitrite  so –ous ending
*No HYDRO for Oxygen

40. Acids & Bases 2

41. Strong Acids and Strong Bases
Since they ______________ disassociate…
…so when HCl is placed in water…
100 molecules of HCl are dissolved in water,
__________and __________ions are produced.
This comes into play for calculating the pH for strong solutions!
completely
100 H+ ions
100 Cl- ions

42. Find the pH of the following solution…
A solution containing 1 mole of hydrochloric acid in 12 L of water
pH measures ________________________________.
concentration of H+ ions
M = mol/L
M = 1 mol / 12L
M = _____ M HCl
_____ M H+
0.0833
0.0833
pH = -log( )
0.0833

43. Find the pH of the following solution…
A solution containing 5 moles of HCl in 10 L of water

44. Find the pH of the following solution…
A solution containing 20 grams of HCl in 10 L of water

45. Exit Slip
Calculate the pH of a solution containing 50 grams of HCl in 2.5 L of water.

46. Measuring the Amount of H+ and OH− Ions in a Solution
_____ Scale- measures the _____________ of [H+] ions in a solution
_____ Scale- measures the concentration of [ ____ ] ions in a solution
Formulas
pH = − (log [H+]) pOH = −(log [OH−])
[H+] = 10−pH [OH−] = 10−pOH
pH + pOH = 14
With the pH scale, we have another way to define acids and bases:
Acids have a pH _________7.0
Bases have a pH _________7.0
Neutral pH ___7.0 pH
concentration
pOH
OH−
below
above =