Transcript Acids, Bases, & Salts

•pH less than 7
•Neutralizes bases(form salts and water)
+
•Forms H (H3O+) ions in solution
•Corrosive-reacts with most metals
•Good conductors of electricity
•Taste sour
HNO3 + H2O  H3
+
O
+ NO3
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Weak Acids do not ionize completely: Acetic,
Boric, Nitrous, Phosphoric, Sulfurous
Strong Acids ionize completely: Hydrochloric,
Nitric; Sulfuric, Hydriodic
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•
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•
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•
HCl- hydrochloric- stomach acid
H2SO4- sulfuric acid - car batteries
HNO3 – nitric acid - explosives
HC2H3O2- acetic acid - vinegar
H2CO3-carbonic acid – sodas
H3PO4- phosphoric acid -flavorings
 pH greater than 7
 Feels slippery, soapy
 Taste bitter, chalky
 Are electrolytes
 Dissolves fats and oils
 Usually forms OH ions
solution
 Neutralizes acids
in
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
Weak Bases: ammonia; potassium carbonate,
sodium carbonate
Strong Bases: sodium hydroxide; sodium
phosphate; barium hydroxide; calcium
hydroxide
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NaOH- sodium hydroxide (LYE) soaps, drain
cleaner
Mg (OH)2 - magnesium hydroxide-antacids
Al(OH)3-aluminum hydroxide-antacids,
deodorants
NH4OH-ammonium hydroxide- “ammonia”
Describe the solution in each of the
following as: 1) acid 2) base or
3)neutral.
A. ___soda
B. ___soap
C. ___coffee
D. ___ wine
E. ___ water
F. ___ grapefruit
LecturePLUS Timberlake
9
Describe each solution as:
1) acid 2) base or 3) neutral.
A. _1_ soda
B. _2_ soap
C. _1_ coffee
D. _1_ wine
E. _3_ water
F. _1_ grapefruit
LecturePLUS Timberlake
10
Identify each as characteristic of an A) acid
or B) base
____ 1. Sour taste
____ 2. Produces OH- in aqueous solutions
____ 3. Chalky taste
____ 4. Is an electrolyte
____ 5. Produces H+ in aqueous solutions
LecturePLUS Timberlake
11
Identify each as a characteristic of an A) acid
or B) base
_A_ 1. Sour taste
_B_ 2. Produces OH- in aqueous solutions
_B_ 3. Chalky taste
A, B 4. Is an electrolyte
_A_ 5. Produces H+ in aqueous solutions
LecturePLUS Timberlake
12
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We use this scale to measure the strength of
an acid or base.
pH is defined as the –log[H+]
pH can use the concentration of hydronium
ions or hydrogen ions.
SOURCE: http://en.wikipedia.org/wiki/Image:PH_scale.png#file
[H+] M
100
10-1
A strong acid
10-2
10-3
10-4
10-6
10-7
10-8
• [H+] is controlled in all
biological organisms, and in
virtually all biochemical
experiments.
10-9
10-10
10-11
10-12
10-14
• Most living cells have a very
narrow range of tolerance for pH,
i.e. [H+].
• The [H+] concentration will be
important (either explicitly or
implicitly) for many other topics
in biology.
10-5
10-13
pH
A strong base
• Each pH unit represents a factor
of 10 difference in [H+].
The pH scale goes from 0 to 14—because [H+][OH-] = 10-14
14
More acidic
More basic
pH
NaOH, 0.1 M
Household bleach
Household ammonia
Lime water
Milk of magnesia
Borax
Baking soda
Egg white, seawater
Human blood, tears
Milk
Saliva
Rain
Black coffee
Banana
Tomatoes
Wine
Cola, vinegar
Lemon juice
Gastric juice
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
[H1+]
1 x 10-14
1 x 10-13
1 x 10-12
1 x 10-11
1 x 10-10
1 x 10-9
1 x 10-8
1 x 10-7
1 x 10-6
1 x 10-5
1 x 10-4
1 x 10-3
1 x 10-2
1 x 10-1
1 x 100
[OH1-]
1 x 10-0
1 x 10-1
1 x 10-2
1 x 10-3
1 x 10-4
1 x 10-5
1 x 10-6
1 x 10-7
1 x 10-8
1 x 10-9
1 x 10-10
1 x 10-11
1 x 10-12
1 x 10-13
1 x 10-14
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
pOH
concentration (moles/L)
10-1
pH = 3
OH-
H3O+
pH = 7
10-7
H3O+ OH-
OH10-14
[H3O+] > [OH-]
acidic
Timberlake, Chemistry
7th
pH = 11
Edition, page 332
H3 O+
[H3O+] = [OH-][H O ] < [OH-]
neutral
basic
3
+
pH = -log [H+]
Kelter, Carr, Scott, Chemistry A World of Choices 1999, page 285
Indicator
Acid
color
Neutral
color
Base
color
Phenolphthalein Colorless Faint pink Dark pink
Bromthymol
blue
Yellow
Green
Blue
Litmus
Red
-----
Blue

pH paper changes
color to indicate a
specific pH value.
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A buffer is a solution that resists changes in
pH when small amounts of acids and bases
are added.
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“Heartburn”
Planting vegetables and flowers
Fish Tanks and Ponds
Blood
Swimming pools
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Digestion-process by which foods are
broken down into simpler substances.
Mechanical digestion-physical process in
which food is torn apart (mouth)
Chemical digestion- chemical reactions in
which large molecules are broken down into
smaller molecules. (stomach and small
intestines)
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Mouth-pH around 7. Saliva contains
amylase, an enzyme which begins to break
carbohydrates into sugars.
Stomach- pH around 2. Proteins are broken
down into amino acids by the enzyme
pepsin.
Small intestine-pH around 8. Most
digestion ends. Small molecules move to
bloodstream toward cells that use them
Digestive system
mouth
esophagus
stomach
small intestine
large intestine