pH and Buffer Flashcards
Substances that dissociates when dissolved in water and produces H+
Arrhenius Acids
Substances that dissociates and release OH- ions
Arrhenius Bases
Limitations onf Arrhenius Theory
- Arrhenius theory is limited to behavior of acids and bases in aqeous solutions and not in non-aqueous media.
- Manu substances do not have H+, but behave as acids (NH4Cl, CO2)
- Substances do not have Oh-, but behave as bases (Na2CO3, CaO)
The complete separation of ions in a crystal lattice when a salt is dissolved
Ionization
Separation of ions in solution when the ions are associated by interionic attraction
Dissociation
Hydrogen-containing substance that donates a proton/H+ to another substance
Bronsted-Lowry Acids
Substance that accepts a proton/H+
Brownsted-Lowry Bases
Molecule that can accept a pair of e- to form a dative bond
Lewis Acids
Molecule that can donate a pair of e- to form a dative bond
Lewis Bases
Acid dissociation constant/Acidity Constant
Ka
TF:
↑ Ka ↑Acidity
↓ pka ↑Acidity
True
Kb
Base ionization constant/Basicity Constant
TF:
↑ Kb ↑Basicity
↓ pkb ↑Basicity
True
pKa
pKa = -logka
pKb
pKb = -logkb
Formula for Strong Acids and Bases
pH = -log [H+]
pOH = -log [OH-]
pH + pOH = pKw
pKa + pKb = pKw
pKw = 14
Formula for Weak acid and Weak Base
WA: pH = √ ka x ca
WB: pOH = √ kb x cb
Solutions that resist pH change even if small amount og strong acid or strong base is added
Buffer
Primary buffer in Blood
Carbonic Acid-Bicarbonate Buffer System
Acid Buffer
Weak acid + Conjugate Base
Ex. Acetic acid and Sodium citrate
Basic Buffer
Weak Base + Conjugate Acid
Ex. Ammonia and Ammonium Chloride
Buffer Equations
Henderson-Hasselbach Equation
Calculate the pH of a buffer Solution
Henderson-Hasselbach Equation
Henderson-Hasselbach Equation
Weak Acid
pH = pKa + log(salt/acid)
pH = (14 - pKb) + log (salt/acid)
Henderson-Hasselbach Equation
Weak Base
pH = pKa + log (base/salt)
The magnitude of resistance of a buffer to pH changes
Buffer Capacity/Effect/Index/Value/Efficiency
Buffer Capacity Equation
Van Slyke’s
Maximum Buffer Capacity formula
0.576*C
Maximum Buffer Capacity
pH = pKa