1. Acids and Bases

2. Acids and Bases Definitions
Demo – Intro to Acids and Bases
What is an indicator?
Universal indicator changes from green to _____ in the presence of acid.
Universal indicator changes from green to _____ in the presence of base.
What do acids and bases make when they neutralize each other?
__________ & __________
Chemical that changes color for an acid or base
RED
BLUE
Salt Water

3. Acids and Bases Definitions
Review Naming Acids and Bases from formula
H2CO3 ________________
Ca(OH)2 ________________
H3N ________________
HC2H3O2 ________________
Review Writing formulas from names:
Hydrofluoric acid ________
Copper (II) hydroxide ________
Magnesium hydroxide ________
d. Sulfurous acid ________
e. Phosphoric acid ________
Carbonic Acid
Calcium Hydroxide
Hydronitric Acid
Acetic Acid HF
Cu(OH)2
Mg(OH)2
H2SO3
H3PO4

4. Arrhenius Model of Acids and Bases
What are acids and bases?
Arrhenius model (1887)
Acid – Contains H+ and produces H+ in solution
Base – Contains OH- and produces OH- in solution
Ex: HCl(g)  H+(aq) + Cl –(aq)
Ex: NaOH(s)  Na+(aq) + OH-(aq)
** What was the problem with Arrhenius’s model?
Ex. NH H2O  NH4+ + OH-
Ammonia (base)
__________________________________________
H+ Cl-
Cl- H+
Acids and bases both dissociate into ions when dissolved in water
Na+ OH-
OH- Na+
Arrhenius didn’t include all bases

5. Bronstead Lowry Model of Acids and Bases
Bronsted-Lowry Model (includes ALL Bases – based on how acids and bases act) Acid – Donates H+ Base – Accepts H+ HX(aq) + H2O(l)   H3O+(aq) + X-(aq) Ex: HF + H2O   H3O+ + F – Ex. NH3(aq) + H2O(l)   NH4+(aq) + OH-(aq)
Look at the products!
A B
A B
B A

6. Summary
Are all Arrhenius acids also Bronsted-Lowry acids? ___ Why? __________________ Are all Bronsted-Lowry acids also Arrhenius acids? ____ Are all Arrhenius bases also Bronstead-Lowry bases? __ Why? ___________________ Are all Bronstead-Lowry bases also Arrhenius bases? ____ Why? _______________________________
Yes
Donates H+
Yes
Contains H+
Yes
Accepts H+ No
Some don’t contain OH- (like NH3)

7. Stations Notes Characteristics Acids Bases Blue Litmus - b. c. Taste
Reaction with metals
Conductivity
Texture
More H+ or OH- ?
pH range
Indicators:
a. Litmus paper
b. Phenolphthalein
(base indicator)
c. Universal Indicator
 a.Red Litmus –
Blue Litmus - b. c.
Examples - Acids and bases are common in both the laboratory and the home:
Laboratory:
Home:

8. Stations Notes Characteristics Acids Bases Blue Litmus - Turns Red
Taste
 Sour
Bitter
Reaction with metals
Yes No
Conductivity
 Yes
Texture
Like Water
Slippery
More H+ or OH- ?
More H+
More OH-
pH range
Less than 7 
More than 7
Indicators:
a. Litmus paper
b. Phenolphthalein
(base indicator)
c. Universal Indicator
 a.Red Litmus – Stays Red
Blue Litmus - Turns Red
b. No change
c. Red
 a.Red Litmus – Turns Blue
Blue Litmus – Stays Blue
b. Turns hot pink
c. Blue
Examples - Acids and bases are common in both the laboratory and the home:
Laboratory:
Home:

9. Acid-Base Reactions

10. DEMO: MOM Rainbow
DEMO (MOM rainbow) – Neutralization reaction of an Antacid.
When do we take antacids?
How do antacids work in your stomach?
What is the formula of Milk of Magnesia?
What type of substance is an antacid? ________How do you know?
Give another example of an antacid.
Why is it called “antacid”?
What is the scientific name for stomach acid?
What is the formula?
Write the equation for magnesium hydroxide (antacid) neutralizing a stomach acid. Predict and name the products. Balance the equation:
_________ + ________ _________ + ________
Acid Reflux
They neutralize the stomach acid
Mg(OH)2
Base It can neutralize the acid
It is anti – acid, does the opposite
Hydrochliric Acid
HCl
HCl Mg(OH)2
MgCl H2O
Product Names: Magnesium Chloride and Water

11. Salt - Ionic compound made up a cation from a metal and an anion from an non-metal
What type of reaction is acid-base neutralization?
Double Replacement Reaction

12. Acid Base Neutralization Reaction
An acid base neutralization reaction is a double replacement reaction that results in a salt and water (pH = 7)
Ex: Hydrochloric acid is neutralized by calcium hydroxide.
HCl Ca(OH)2  ________ + _________
CaCl2 H2O
Product Names: Calcium Chloride and Water
Now its time for you to work on the practice! Use your notes to help you answer the questions!

13. pH Scale

14. pH Scale Tenfold Potential of Hydrogen [H+] = [OH-] neutral (pH = 7)
Molarity (M)
[H+] represents the molar concentration {____________} of the hydrogen ions.
[H+] 1x 100M x 10-14M
pH scale:
**A change of one pH unit represents a ____________change in ion concentration.
What does pH stand for? ______________________ 
A pH of 4 is ___________________ than a pH of 5
A pH of 10 is _________________________ than a pH of 5
Tenfold
Potential of Hydrogen
[H+] = [OH-] neutral (pH = 7)
[H+] < [OH-] base (pH above 7)
[H+] > [OH-] acid (pH below 7)
10 times stronger
100,000 times weaker

15. To find pH if you know the Hydrogen ion concentration, use the following formula: pH = -log[ H+ ]
Calculate the pH of each solution: Solution 1 has a [H+] equal to 1x10-7M Solution 2 has a [H+] equal to 3.6 x 10-9M
pH = 7
pH = -log(1E-7)
Answer: ________________
Is the solution an Acid , Base , or Neutral ?
pH = -log(3.6E-9)
pH = 8.44
Answer: ________________
Is the solution an Acid , Base , or Neutral ?

16. To find the H+ concentration when given the pH use: [H+] = 2nd log (-pH)
Calculate the [H+] (concentration) for each solution. Solution 1 has a pH of 4.0 Solution 2 has a pH of 11.5
1 x 10-4 M
Answer: ________________
[H+] = 2nd log (-4)
Is the solution an Acid , Base , or Neutral ?
3.16 x M
Answer: ________________
[H+] = 2nd log (-11.5)
Is the solution an Acid , Base , or Neutral ?

17. To find hydroxide concentration (or the [H+] if not given the pH)
To find hydroxide concentration (or the [H+] if not given the pH). Use the following formula: Kw = [H+][OH-] = 1 x 10-14
At 298K, the [OH-] is 1.0 x 10-11M. Find the [H+] in the solution and determine whether the solution is acidic, basic, or neutral.
Formula:
Work:
Answer: __________________
Kw = [H+][OH-]
1E-14 = [H+](1E-11)
.001 M or 1 x 10-3 M
Is the solution an Acid , Base , or Neutral ?

18. To find pH if you know the hydroxide ion concentration
To find pH if you know the hydroxide ion concentration. Use the following formulas: Kw = [H+][OH-] = 1 x & pH = -log[ H+ ]
At 298K, the [OH-] is 1.0 x 10-10M. Find the pH of the solution and determine whether the solution is acidic, basic, or neutral.
Formulas:
Work:
Answer: _______
Kw = [H+][OH-] = 1 x & pH = -log[ H+ ]
1 x = [H+](1E-10) [H+] =
pH = -log [ H+ ]
pH = -log( )
1E-4 M
1E-4 M
pH = 4
Is the solution an Acid , Base , or Neutral ?

19. Strengths of Acids and Bases
Weak
Strong

20. Acid Strength
Acids that dissociate into ions (ionize) completely in aqueous solutions are called _________ acids; produce the __________ number of ions, so they are______conductors of electricity and therefore strong acids are _______ electrolytes.
Examples: HCl, HNO3, HI, H2SO4
Acids that ___________ ionize in aqueous solutions are called ________ acids; cannot conduct electricity as efficiently and therefore, weak acids are ______ electrolytes.
Examples: HC2H3O2, HF, HCN, H2CO3
STRONG
maximum
good
STRONG
partially
WEAK
WEAK

21. Base Strength completely
1. Bases that ionize ____________in aqueous solutions into metal ions and __________ ions are called _________ bases. Base must contain _____ to be a strong base. Examples: NaOH, KOH, RbOH, CsOH, Ca(OH)2 2. Bases that ____________ ionize in solutions are called ________ bases. Examples: NH3, CH3NH2 (methylamine)
hydroxide
STRONG
OH-
partially
WEAK

22. Summary
100
Strong acids and bases dissociate ____% into ions in solution.
Weak acids and bases dissociate about __% into ions in solution. 1

23. Difference between Strength and Concentration
Concentration (dilute or concentrated) refers to the ____________of the acid or base molecules dissolved in a volume of solution (molarity = M).
Strength (weak or strong) refers to the degree of ____________, which means how easily the acid or base separates into _____.
Example: 0.6 M HCl or 6 M HC2H3O2
Which more concentrated?______
Which is stronger? _________
Which acid has a higher pH?_____ How do you know?
Which acid has a lower pH? ________ How do you know?
amount
dissociation
ions
HC2H3O2
HC2H3O2
HCl
Strong Acid
HC2H3O2
Weak Acid

24. The degrees of dissociation into ions for HCl and HC2H3O2
1% dissociation (ionization)
Both, HC2O3H2 molecules & ions are in a solution.
Molecules > Ions
100% dissociation (ionization)
No HCl molecules, just ions
Molecules < Ions