Chapter 10- Acids And Bases Flashcards
Arrhenius acid vs base
Acid- dissociate to form excess of H+
Base- dissociate to form excess of OH-
Brønsted-Lowry acid vs base
Acid- donates H+ ions
Base- accepts H+ ions
Lewis acid vs base
Acid- electron pair acceptor
Base- electron pair donor
One way a Lewis acid can be used in organic chemistry
As a catalyst
Oxyanions to Oxyacids naming
- ite (less O) it will end with -ous acid.
- are (more O) if will end with -ic acid
Amphoteric and amphiprotic
Amphoteric- both - and +
Amphiprotic- lose or gain a proton (H+)
Water dissociation constant (Kw)
10^-14 (concentration of each ion- H3O+ and OH- - is 10^-7) ONLY TEMPERATURE DEPENDENT
Smaller Ka or Kb means….
Weaker acid or weaker base
Generally speaking Ka and Kb values…
Ka smaller than 1 = weak acid
Kb smaller than 1 = weak base (almost always amines)
7 most common strong acids
- HCl
- HClO4
- HClO3
- HI
- HBr
- H2SO4
- HNO3
Find pH or pOH based on Ka or Kb
p value = m -0.n
Ex. Ka = 1.8 x 10^-5
So 5 - 0.18 = 4.82
Acetic acid
CH3COOH
Mathematical relationship between Ka, Kb, and Kw
Ka x Kb = Kw
Buffers and 2 examples
Weak acid or base and its salt. Ex: acetic acid and sodium acetate. Ex2: ammonia and ammonium chloride
Sodium acetate
CH3COO-Na+
Ammonia
NH3
Ammonium chloride
NH4+Cl-
Bicarbonate buffer system
H2CO3 and HCO3- are in the blood plasma to keep its pH within the narrow range. Tied to respiratory system and breathing out CO2 which is not very soluble.
Estimate pH or pOH of buffer solution
pH= pKa + log (base/acid) OR pH= pKb + log (acid/base)
When does pH = pKa?
Half equivalence points in a titration. Buffering capacity is also optimal at this pH
Where Ka and equivalence points are on a titration curve?
Assuming pH is y-axis and volume added is x-axis.
pKa is the middle of the horizontal line and equivalence point is middle of the vertical line.
Gram equivalence weight
Molar mass / number of acidic or basic equivalence included
Generally How to answer dissociation questions given molarity and Ka
Ka = x^2 / molarity
