Equations
Kw =? (give both equations)
1. Kw = [H3O+][OH-]
2. Kw = Ka(of a W.A.) x Kb(of its C.B.)
Does dilution change the pH of a buffer?
Nope
What is a salt formed by?
A salt is formed by the reactions of an acid and a base
How does the acidity of the 1st H in a polyprotic acid compare to the acidity of the 2nd H and so on?
What is the molar solubility represented by?
"s"
14.00 = ?
14.00 = pH + pOH
Complete the following:
The Stronger the acid, the __ Ka, the ___ Kb of it's C.B., the ___ pKa, the ___ [H+], the ___ [OH-], the ___ pH, and the ___ pOH.
Stronger the acid, the higher the Ka, the lower the Kb of it's C.B., the lower pKa, the higher [H+], the lower [OH-], the lower the pH, and the higher the pOH.
When do we know if we have a buffer?
When there is a W.A. and a salt containing it's C.B.
or
When there is a W.B. and a salt containing it's C.A.
At what point in a titration do we have a "perfect" buffer and what does a "perfect" buffer look like?
at half equivalence point (log(1)=0)
pH = pKa
a) How will a complex agent affect the solubility?
b) How will a common ion affect the solubility?
a) increase solubility
b) decrease solubility
H.H. Equation?
pH = pKa + log(basic component/acidic component)
Will these scenarios produce neutral, acidic, or basic salts?
a) 1 rxn happens, hydronium is produced
b) both rxn's happen
c) 1 rxn happens, hydroxide is produced
a) acidic
b) neutral
c) basic
What are the 2 steps in determining the pH of a salt?
1. Ionization - salt breaks up into it's respective ions
2. Hydrolysis - each ion is added to water and we see if a rxn occurs or not
(Once we have a rxn use Ka and/or Kb equations)
Describe with pH's how these titration graphs would look like: (assume graphs begin with substance on the left)
a) S.A. vs S.B.
b) W.B. vs S.A.
c) W.A. vs S.B.
a) begins with a pH way below 7.00 & ends at a pH way above 7.00
b) begins with a pH above 7.00 & ends at a pH way below 7.00
c) begins with a pH below 7.00 & ends at a pH way above 7.00
If we have a Ksp of 4.5x10-3 and we have a Kf of 5.8x106. What is the value of the KspKf?
KspKf = 2.6x104
1. What is the Ka equation? (give in terms of x)
2. % HA diss. equation?
1. Ka = x2/[HA]i - x
2. % = [HA]diss./[HA]i(100) or x/[HA]i(100)
What is the Ksp expression in terms of "s" for copper (II) phosphate?
Ksp = [Cu2+]3[PO43-]2
Ksp = (3s)3(2s)2
Ksp = 108s5
What effects the pH of a buffer?
The addition of strong acids and bases
What is the equivalence point volume of a solution containing 30.0mL of 0.25M HCN that is titrated with 0.20M NaOH?
volume = 37.5 mL
Will a ppt. form or not?
a) Qsp > Ksp
b) Qsp < Ksp
a) ppt. will form
b) no ppt. will form
What equation is valid at the equivalence point in a titration?
MAVA/coeff. = MBVB/coeff.
What do we have at equivalence point for:
a) W.A. titrated with a S.B. (S.B. added to W.A.)
b) W.B. titrated with a S.A. (S.A. added to W.B.)
a) basic salt
b) acidic salt
What is the pH of a solution that contains 2.0M HF & 1.5M KF? (Ka HF=3.5x10-4)
pH = -log(3.5x10-4) + log(1.5/2.0)
pH = 3.33
While doing titration calculations we are left with only a value for a strong base and a salt. Describe how we would solve for the pH from there?
*Strong base dominates the pH of the solution (same idea with strong acids)
-Strong base will break up into its respective ions (1 will be OH-)
-Use OH- concentration to get to pH value
What are these compounds?
a) Barium fluoride
b) Silver (I) Oxalate
c) Lead (II) Sulfate
a) BaF2
b) Ag2C2O4
c) PbSO4