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Bronsted - Lowry Acids and Bases
proton donor
protonacceptor
(they actually didn't work together)* Explains how acids and bases can work without the presence of water
An acid-base reaction is a proton transfer reaction.
CH3COOH + NH3
Conjugate Acid-Base Pair: a pair of molecules or ions that are related to one another by the gain or loss of a proton
Acids form conjugate basesBases form conjugate acids
1. Acids can be +, neutral or -2. Bases can be neutral or -3. Acids can be monoprotic, diprotic or triprotic.4. Amphiprotic5. In some cases, not all H's are given up:
acetic acidphenol
6. Inverse relationship b/w strength of acid and its conjugate base.
Determining Equilibrium Position
Strong acids:
HCl + H2O Cl- + H3O+
Weak acids:
CH3COOH + H2O CH3COO- + H3O+
CH3COOH + NH3 CH3COO- + NH4+?
CH3COOH + NH3 CH3COO- + NH4+?
1. Identify the acids.
acid acid
CH3COOH + NH3 CH3COO- + NH4+?
1. Identify the acids.
acidacid
2. Determine which acid is stronger:
CH3COOH + NH3 CH3COO- + NH4+?
1. Identify the acids.
acidacid
2. Determine which acid is stronger.3. Do the same with the bases (Identify the stronger and weaker bases)
basebase
CH3COOH + NH3 CH3COO- + NH4+
acidacid
basebase
1. Identify the acids.2. Determine which acid is stronger.3. Identify the stronger and weaker bases:4. Stronger always react to give weaker:
H3O+ + I- H2O + HICH3COO- + H2S CH3COOH + HS-
How do we use IONIZATION CONSTANTS?
an equilibrium constant for weak acids or weak bases
All ionizations of weak acids or bases in water are at equilibrium.We use equilibrium constants to quantitatively show how strong a weak acid or base is.
HA + H2O A- + H3O+
K = [A-][H3O+][HA][H2O]
Ka = K[H2O] =[A-][H3O+]
[HA]
because water is the solvent and []changes VERY little when HA is added,we combine it with K to give a new constant
ACID IONIZATION CONSTANT
Properties of acids and bases:1. Neutralization
a) Reaction with metal hydroxides
b) Reaction with Metal oxides:
c) Reaction with Carbonates and bicarbonates
HCl + CaCO3
DOUBLEDISPLACEMENT
NaHCO3
(a basic salt)
react with vinegar to get pocketsof CO2 in batter
(yogurt, chocolate, buttermilk)
leavening agents
cream of tartarNaHCO3
andpotassium hydrogen tartrate = weak acid)
2. Reaction with metalsSINGLE DISPLACEMENT
3. Reaction with ammonia and amines
HCl + NH3
HCl + CH3-NH2
Cl - H