1. Chapter 8- Acids, Bases, & salts

2. HCl + H2O  H3O+ + Cl– Definitions Acids
Ionize to form hydronium ions (H3O+) in water (Arrhenius)
Donates a proton to the base (Bronsted)
Accepts a pair of electrons from base (Lewis)
HCl + H2O  H3O+ + Cl–

3. NH3 + H2O  NH4+ + OH- Definitions Bases
Dissociate or ionize to form hydroxide ions (OH-) in water (Arrhenius)
Accepts a proton from acid (Bronsted)
Donates pair of electrons to acid (Lewis)
NH3 + H2O  NH4+ + OH-

4. Definitions Indicator substance that changes color in an acid or base
Examples:
litmus - red/blue
phenolphthalein - colorless/pink
goldenrod - yellow/red
red cabbage juice - pink/green

5. Properties BASES ACIDS bitter taste corrosive electrolytes
sour taste
corrosive
Electrolytes (solns that conduct electricity when dissolved in water)
turn blue litmus paper red
react with metals to form H2 gas
pH below 7
bitter taste
corrosive
electrolytes
turn red litmus paper blue
slippery feel
Many contain –OH groups
pH above 7

6. Weak ACIDS Strong ACIDS
Ionize completely in water
Strong electrolyte
Solutions of these acids have as many hydronium atoms as the acid can possible form
Do not ionize completely in water
Weaker electrolyte
Some acid molecules will combine with water to form ions
Some of these ions will recombine to form molecules of the weak acid

7. Uses ACIDS H3PO4 - soft drinks, fertilizer, detergents
H2SO4 - fertilizer, car batteries
HCl - gastric juice, swimming pools
HC2H3O2 - vinegar

8. Strong Bases Weak Bases
Metal + OH
All IA and IIA hydroxides are strong
Dissociate completely in water into ions
Strong electrolyte
Do not dissociate completely in water
Weaker electrolyte

9. Uses BASES NaOH - lye, drain and oven cleaner
Mg(OH)2 - laxative, antacid
NH3 - cleaners, fertilizer
Ca(OH)2- treating acid soil, cement, mortar

10. SAFETY Any acid or base can be very dangerous in concentrated form
Always wear goggles and gloves if you must work with these!!!!

11. pH Scale pH a measure of the concentration of H3O+ ions in solution
measured with a pH paper, pH meter or an indicator with a wide color range
Ranges from 0-14
INCREASING
ACIDITY
INCREASING
BASICITY
NEUTRAL

12. pH of Common Substances
pH Scale
pH of Common Substances

13. CALCULATING PH Can calculate using the molarity of H+ ions
Equation is as follows:
pH= -log ([H+])
Type in negative sign, press log button, left parenthesis, H+ concentration, right parenthesis
Example: Determine the pH of an HCl solution with a concentration of M
pH= -log (0.0001)
pH= 4

14. ConcepTest
Which of the following "molecular" pictures best represents a concentrated solution of the weak acid HA? A B

15. ConcepTest Is the following statement TRUE or FALSE?
A strong acid has a lower pH than a weak acid.
FALSE - Strong/weak refers to amount of ionization whereas pH refers to concentration of H+.

16. Common chemicals

17. SOAP & Detergent Chemical composition How they work
Improve water’s ability to clean
Soaps are salts of potassium and fatty acids, basic with –COO- chains
Detergents are salts of sodium, potassium, and sometimes ammonium, basic with –SO3- chains
Negatively charged ends dissolve in water, other end dissolves in oil, dirt, and grease

18. Household CLeaners Ammonia Bleach Ammonia is a weak base
[OH-] concentration low, but there is enough ions to help emulsify thin layers of dirt and fingerprints
NH3 + H2O  NH4+ + OH-
A strong disinfectant
A chemical substance that kills harmful bacteria or viruses
Changes stains to colorless form because of the oxygen atom in the hypochlorite ion, ClO-
Ammonia and Bleach should not be mixed because noxious chloramine gas, NH2Cl is formed!!!

19. Healthcare Antacids Shampoo We will see how these work in labs
Made of magnesium hydroxide or sodium bicarbonate
pH balanced between 5-8
If shampoo is too basic, will cause strands of hair to swell
Shampoo that is too acidic dries out hair

20. The refrigerator trick
The apple was cut at the same time
One side was moistened with lemon juice
Why does this work?
The citric acid in lemon juice helps antioxidants in the apple that react with oxygen can react with other substances in the apple

21. Reactions with acids and bases

22. Neutralization Reaction
Chemical reaction between an acid and a base.
Products are a salt (ionic compound) and water.

23. Neutralization Reaction
ACID + BASE  SALT + WATER
HCl + NaOH  NaCl + H2O =
Neutralization does not always mean pH = 7.

24. Neutralization Reaction
KOH + HNO3  H2O + KNO3
Acid?
Base?
Salt?
HNO3
KOH
KNO3

25. Neutralization reactions
Not all produce neutral solutions
final pH depends on amounts and strength of acids and bases that are combined
If a strong acid reacts with an equal amount of weak base, the resulting solution will still be acidic
If a strong base reacts with an equal amount of weak acid, the resulting solutions will still be basic

26. Titration Titration standard solution
unknown solution
Titration
Process in which a standard solution is used to determine the concentration of an unknown solution.

27. Titration dramatic change in pH Equivalence Point
Point at which equal amounts of H3O+ and OH- have been added.
Determined by…
indicator color change
dramatic change in pH

28. Equivalence point The equivalence point is not always neutral
When strong base reacts with strong acid, EP is neutral
When strong base reacts with a weak acid or strong acid reacts with weak base, EP will not be at pH 7

29. Equivalence points Weak Acid titrated with strong base
Weak base titrated with strong acid

30. Salts Origin of NaCl in US Uses of NaCl
Underground deposits from dried up ancient seas
Uses of NaCl
Sodium in your diet
Seasoning and preserving food
Ceramic glazes
Soap
Water softeners
De-icing of highways
Fire extinguishers