Transcript Acids, Bases, and Salts

Acids and Bases
http://www.unit5.org/chemistry/AcidBase.html
http://www.chalkbored.com/lessons/chemistry-11/acid-bronsted.ppt
Properties
electrolytes
electrolytes
sour taste
bitter taste
turn litmus red
turn litmus blue
react with metals to
form H2 gas
slippery feel
vinegar, milk, soda,
apples, citrus fruits
ammonia, lye, antacid,
baking soda
ChemASAP
Acid vs. Base
Different
Alike
pH < 7
Affects pH
and
litmus paper
Topic
sour taste
react with
metals
Acid
Different
pH > 7
Topic
Related to
H+ (proton)
concentration
pH + pOH = 14
Base
bitter taste
does not
react with
metals
Common Acids and Bases
Strong Acids (strong electrolytes)
HCl
HNO3
HClO4
H2SO4
hydrochloric acid
nitric acid
perchloric acid
sulfuric acid
Weak Acids (weak electrolytes)
CH3COOH
H2CO3
acetic acid
carbonic
Strong Bases (strong electrolytes)
NaOH
KOH
Ca(OH)2
sodium hydroxide
potassium hydroxide
calcium hydroxide
Weak
Weak Base
Base (weak
(weak electrolyte)
electrolyte)
NH
NH43OH
ammonia
NH3 + H2O  NH4OH
Kotz, Purcell, Chemistry & Chemical Reactivity 1991, page 145
Common Acids
Sulfuric Acid
H2SO4
Battery acid
Nitric Acid
HNO3
Used to make fertilizers
and explosives
Phosphoric Acid
H3PO4
Food flavoring
Hydrochloric Acid
HCl
Stomach acid
Acetic Acid
Carbonic Acid
CH3COOH
H2CO3
Vinegar
Carbonated water
OH1-
Common Bases
hydroxide
ion
Name
Formula
Common Name
Sodium hydroxide
NaOH
lye or caustic soda
Potassium hydroxide
KOH
lye or caustic potash
Magnesium hydroxide
Mg(OH)2
milk of magnesia
Calcium hydroxide
Ca(OH) 2
slaked lime
Ammonia water
NH
H 2O
NH43.OH
household ammonia
NH41+ + OH1ammonium hydroxide
Formation of Hydronium Ions
1+
1+
1+
+
H+
H2O
hydrogen ion
(a proton)
water
H3O+
hydronium ion
Arrhenius Acid
Any substance that releases H+ ions as the
only positive ion in the aqueous solution.
1-
1+
+
+
HCl
H2O
H3O+
Cl-
hydrogen chloride
(an Arrhenius acid)
water
hydronium ion
chloride ion
Arrhenius Bases and Their Properties
According to the definition of Arrhenius a:
Base - "a substance whose water solution yields...
hydroxide ions (OH-) as the only negative ions."
Are NaOH and NH3 considered to be Arrhenius bases? YES
1) Bases are electrolytes
Dissociation equation for NaOH
NaOH(s)
Na1+(aq) + OH1-(aq)
Dissociation equation for NH3
NH3(g) + H2O(l)
NH41+(aq) + OH1-(aq)
2) Bases cause indicators to turn a characteristic color
3) Bases neutralize acids
NaOH(aq) + HCl(aq)
NaCl(aq) + H2O(l)
4) Water solutions of bases tasted bitter and feel slippery.
Each of the following unbalanced equations represents a
reaction between a Arrhenius acid and base. Identify those
in each reaction:
H2CO3 + NH4OH → (NH4)2CO3 + H2O
KOH + H3PO4 → K3PO4 + H2O
HF + NaOH → NaF + H2O
Ba(OH)2 + HNO2 → Ba(NO2)2 + H2O
Brønsted-Lowry Acids and Bases
Acid = any substance that donates a proton.
Base = any substance that accepts a proton.
d+
1-
1+
d-
+
HCl
H2O
H3O+
Cl-
(acid)
(base)
hydronium ion
chloride ion
Brønsted-Lowry Acids and Bases
Acid = any substance that donates a proton.
Base = any substance that accepts a proton.
d+
1-
1+
d-
+
HCl
H2O
H3O+
Cl-
(acid)
(base)
hydronium ion
chloride ion
Brønsted-Lowry Acids and Bases
d-
1-
1+
d+
+
NH3
H2O
(base)
(acid)
NH4+
ammonium ion
OH-
hydroxide ion
Identify the Bronsted-Lowry acid and the Bronsted-Lowry
base in each reaction.
NH4+(aq) + CN- (aq) → HCN (aq) + NH3 (aq)
(CH3)3N(aq) + H2O → (CH3)3NH+(aq) + OH-(aq)
HCHO2(aq) + PO43- → CHO2-(aq) + HPO42-(aq)
HSO4-(aq) + CO32- → SO42- (aq) + HCO3-(aq)
Definitions
 Lewis
• Acids are electron pair acceptors.
• Bases are electron pair donors.
Lewis
base
Lewis
acid
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Acid Definitions
Lewis Acid
Brønsted-Lowry
Arrhenius
acids
Arrhenius Acids and Bases
Acids release hydrogen ions in water.
Bases release hydroxide ions in water.
An acid is a substance that produces hydronium ions, H3O+,
when dissolved in water.
Brønsted-Lowry Definitions
A Brønsted-Lowry acid is a proton donor; it donates a hydrogen ion, H+.
A Brønsted-Lowry base is a proton acceptor; it accepts a hydrogen ion, H+.
Lewis Definitions
A Lewis acid is a substance than can accept (and share) an electron pair.
A Lewis base is a substance than can donate (and share) an electron pair.
Acid Definitions
Lewis acids
The Arrhenius model of acids
and bases was broadened by
the Brønsted-Lowry model.
Brønsted-Lowry
The Lewis acid-base model is
the most general in scope.
Arrhenius
acids
Ralph A. Burns, Fundamentals of Chemistry 1999, page 483
The Lewis definition of an acid
includes any substance that
is an electron pair acceptor;
a Lewis base is any substance
that can act as an electron pair
donor.
Acid Definitions
Lewis acids
The Arrhenius model of acids
and bases was broadened by
the Brønsted-Lowry model.
Brønsted-Lowry
The Lewis acid-base model is
the most general in scope.
Arrhenius
acids
Ralph A. Burns, Fundamentals of Chemistry 1999, page 483
The Lewis definition of an acid
includes any substance that
is an electron pair acceptor;
a Lewis base is any substance
that can act as an electron pair
donor.
Acid – Base Systems
Type
Acid
Base
Arrhenius
H+ or H3O +
producer
OH - producer
BrønstedLowry
Lewis
Proton (H +)
donor
Proton (H +)
acceptor
Electron-pair
acceptor
Electron-pair
donor