Acids, Bases, and pH Acids, Bases, and pH Acids, Bases, and pH Acids, Bases, and pH.
ACIDS AND BASES - Foothill High School
Transcript of ACIDS AND BASES - Foothill High School
Turn to Page 43 in your
Standards Book
Standard 5 – Acids, Bases and Salts are
three classes of compounds that form ions
in water solutions
Standard 5a – Students know the
observable properties of acids, bases and
salt solutions
Acids
Produce H+ ions in water
PROPERTIES:
Taste sour
Are electrolytes (when dissolved in water can
conduct electric current)
React with metals to form H2 gas
React with bases to form salts and water
Bases
Produce OH- ions in water
PROPERTIES:
Taste bitter
Are electrolytes
Feel soapy, slippery
React with acids to form salts and water
Identification Check
Identify each as characteristic of an
A) acid or/and
B) base
____ 1. Sour taste
____ 2. Produces OH- in aqueous solutions
____ 3. Bitter taste
____ 4. Is an electrolyte
____ 5. Produces H+ in aqueous solutions
ANSWERS
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. Bitter taste
A, B 4. Is an electrolyte
_A_ 5. Produces H+ in aqueous solutions
Hydrogen ions
Hydrogen ions in an aqueous solution
have several names
Proton: H+
Hydrogen ion: H+
Hydronium : H3O+
Turn to Page 45 in your
Standards Book
Standard 5c – Students know strong acids
and bases fully dissociate and weak acids
and bases partially dissociate
DISSOCIATION
Dissociation: When ionic compounds
dissolve to produce ions
Dissociation of ionic compounds occurs
when water molecules “pull apart” the ionic
crystal.
Examples of Dissociation
NaCl(s) → Na+(aq) + Cl-(aq)
Na2SO4 (s) → 2 Na+(aq) + 1 SO42-
(aq)
Acid: HClO4(s) → H+(aq) + ClO4
-(aq)
Base: Mg(OH)2 (s) → Mg2+(aq) + 2 OH– (aq
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Strengths of Acids and Bases
Strong acids and bases completely ionize or
dissociate (100%) in aqueous solutions
Acid: HCl + H2O H+ (or H3O+) + Cl-
Base: NaOH Na+ (aq) + OH-(aq)
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Strong and Weak
Acids and Bases
Common Strong acids
HCl, HNO3 , H2SO4
Most other acids are weak (Acetic
Acid - HC2H3O2; examples of a weak
acid, H3PO4, HCN, HF, H2CO3)
Strong bases - NaOH, KOH, & Ca(OH)2
Most other bases are weak i.e. NH3.
H+ A - H+ A - HA
A - H+ A - H+ A –
H+ A - H+ A - H+
A - HA H+ A -
H+ A - H+ A - H+
HA HA HA HA
HA HA HA
H+ A - HA HA
HA HA H + A –
HA H + A – HA HA
H+ A- H+ A- H+ A- H+ A- HA
A- H+ A- H+ A- H+ A- H+ A -
H+ A- HA H+ A- H+ A- H+ A-
A- H+ A- H+ A- H+ A- H+ A- H+
H+ A - H + A - H + A - HA H + A -
A- H+ A- H+ A- H+ A- H+ A–
H+ A- H+ A- H+ A- H+ A- H+
A- H+ A- H+ A- H+ A- H+ A-
HA A- H+ A- H+ A- H+ A- H+
HA HA H+ A- HA HA HA
HA HA HA HA HA H+ A-
H+ A- HA HA HA HA HA
HA HA H+ A- HA HA HA
HA HA HA H+ A
- HA HA
H+ A- HA HA HA HA HA
HA HA HA H+ A
- HA HA
H+ A- HA HA HA HA HA
HA HA H+ A- HA HA HA
DILUTE CONCENTRATED
ST
RO
NG
W
EA
K
STRONG ACIDS
Dissociate nearly 100%
HA H1+ + A-
WEAK ACIDS
Dissociate very little
HA H1+ + A-
Acids: Concentration vs. Strength
Strength vs. Concentration The words concentrated and dilute
refers to the number of moles of acid
or base in a given volume
The words strong and weak refer to the
extent of ionization of an acid or base
Is a concentrated, weak acid possible?
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NEUTRALIZATION
Neutralization reaction: Acid reacts with
base to give salt (Generic term not just
NaCl) and water.
Example: HCl + LiOH → LiCl + H2O
Some Common Acids
hydrochloric acid ( HCl)
nitric acid
phosphoric acid
sulfuric acid
acetic acid (vinegar)
Ascorbic acid (Vitamin C) – citrus fruits
Some Common Bases
NaOH sodium hydroxide
KOH potassium hydroxide
Ba(OH)2 _____________________
Mg(OH)2 _____________________
Al(OH)3 aluminum hydroxide
SVANTE ARRHENIUS
Acid Acids produce H+ in water
water HCl H+ + Cl-
Base Bases produce OH- in water
water
NaOH Na+ + OH-
Acid Acids produce H+ in water
water HCl H+ + Cl-
Base Bases produce OH- in water
water
NaOH Na+ + OH-
pH
Is the measure of the acidity or basicity of the
solution ( how acidic or basic a solution is)
pH means “hydrogen power” or power of
hydrogen
pH of Some Common Acids
gastric juice 1.0
lemon juice 2.3
vinegar 2.8
orange juice 3.5
coffee 5.0
milk 6.6
pH of Some Common Bases
blood 7.4
tears 7.4
seawater 8.4
milk of magnesia 10.6
household ammonia 11.0
Learning Check pH7
Identify each solution as
1. acidic 2. basic 3. neutral
A. _____ HCl with a pH = 1.5
B. _____ household cleaner pH = 12.0
C. _____ Sprite soft drink pH = 3.0
D. _____ water pH = 7.0
E. _____ orange juice pH = 3.3
F. _____ Pancreatic fluid pH = 7.7