8/11/2011
pH
The pH of 0.010 M HClO4
The pH of 0.15 M propionic acid
The pH of 0.10 M pyridine
The pH of 0.10 M sodium bromide
The pH of 0.11 M hydrazinium bromide
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The expression, ‘birds of a feather
flock together’, can be restated in
slightly more scientific terms to help
explain solubility observations
If you’re
not part
of the
solution…
Of the solvents water or carbon
tetrachloride, sulfur (S8), is soluble in this.
Of the solvents: CCl4, H2O, or 0.4 M HCl,
Li2O is most soluble in this
S8
It is the Eocell for the process to clean up
tarnished silver:
3 Ag+(aq) + Al(s) → 3 Ag(s) + Al3+(aq)
Ag + + e– → Ag
Al3+ + 3 e– → Al
+0.80
–1.66
It is the value of n (# of e–s) in the
balanced electrochemical cell reaction
that is used to generate power on
space missions (the product is water!):
H2(g) + 2 OH–(aq) → 2 H2O(ℓ)
O2(g) + 2 H2O(ℓ) → 4 OH–(g)
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…you’re part of
the precipitate
It is the solubility constant expression
for the dissolution of manganese(IV)
phosphate
The molar solubility of a lead(II) iodate,
Pb(IO3)2, solution; Ksp is 2.6 x 10–13
The phenomenon that occurs when
0.10 M sodium phosphate is added
to a saturated solution of Pb3(PO4)2
The equation that would be used to
determine the freezing point of snow
with rock salt thrown on it
The mass of silver(I) sulfate
(MM = 311.79 g/mole) that can
dissolve in 1.0 L of water at 25 °C;
Ksp of Ag2SO4 at 25 °C = 1.4 x 10–5
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Tipping the balance
SO3(g) + NO(g)
SO2(g) + NO2(g)
Adding NO3(g)
S2O82–(aq) + 3 I–(aq)
2 S2O42–(aq) + I3–(aq)
Adding KI
Ba(OH)2●8 H2O(s) + 2 NH4Cl(s)
BaCl2(s) + 2 NH3(g) + 10 H2O(ℓ)
ΔH = + 480.4 kJ
Heating the reaction
2 N2O5(g)
4 NO2(g) + O2(g)
Increasing the pressure
BrO3– + 5 Br–(aq) + 6 H3O+(aq)
3 Br2(aq) + 9 H2O(ℓ)
Adding sodium hydroxide
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Free
Energy!
A positive value of ΔG tells this about a
chemical reaction.
The value of ΔG° for the following
reaction (at 25 °C):
CaCO3(s)
ΔHf° kJ/mole –1206.9
ΔS° J/mole•K 92.90
CaO(s) + CO2(g)
–635.1
39.75
–393.5
213.7
The value of ΔG of the dissolution
of silver(I) carbonate at equilibrium.
ΔG° = +63.55 kJ
The temperature at which the following
reaction just becomes spontaneous:
2NO(g) + O2(g)
ΔHrxn° kJ
ΔSrxn° J/K
2 NO2(g)
–114
–147
The value of Ksp, at 25 °C, of the
following reaction:
Ag2CO3(s)
2Ag+(aq) + CO32–(aq)
ΔG° = +63.55 kJ (at 25 °C); R = 8.314 J/K
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Potporri
Ksp is short for this
In spontaneous processes, this tends
to increase
The strongest acid (by name):
HF, HNO2, HCNO
If you add an acid or a base to this type
of solution, the pH will not change much
ln[concentration]
This graph tells us that a reaction is this
order
time
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pH
If you’re not …you’re
part of the
part of the
solution…
precipitate
Tipping
the
Balance
Free
Energy!
Potpourri
Solubility
Product
constant
(ΔG = –)
ΔGo=
Entropy
ΔHo-TΔSo Universe
Products (178.3kJ),
(160.55J/K)
= 130.46 kJ increases
Nonspontaneous
2.00
Ka = 1.3x10–5
pH=2.85
Kb = 1.7x10–9
pOH=4.88
pH=9.11
Neither an
acid nor base,
pH=7.00
(pure water)
Kb = 1.3x10–6;
Ka=7.69x10–9
pH=4.54
“Like dissolves It precipitates3(ΔG = +);
(already satd’, PO4 No change
Spontaneous
like”
Is a common ion)
CCl4,
Both S8 and
CCl4 are
non-polar
Mn3(PO4)4;
3Mn4+ + 4 PO43–
Ksp =
[Mn4+]3[PO43–]4
0.4 M HCl;
Li2O is a Tf = iKfm Reactants
base
Every eleemnt
Is balanced, so
Balanced charges
(add product 2e- to 1st RXN
& reactant 4e- to 2nd RXN)
Lowest common
denominator
Products
2.6x10-13=[2x]2[x]
x = 4.02x10-5
= +2.46 V
Ag2SO4 
2Ag+ + SO42–
Ksp=1.4x10-5=
[2x]2[x]
At equilib., so no
Driving force
(defin’ of =lib.)
G = 0 = Go + RTlnQ
Where Q is now K
Go = -RTlnK
A buffer
ΔG=ΔGo
Reactants
x=0.015183 M SO42- =Ag2SO4
(0.015183 mol/L)(1L)(311.79g/mol)
n=4
HF
6.8 x 10–4
ΔG= 0
Pb(IO3)2 
Pb2+ + 2IO3–
Eocell =
+0.80 + 1.66V
ΔGo=ΔHo-TΔSo
0=ΔHo-TΔSo
ΔHo=TΔSo
T=775.5 K
+RTlnQ 
ΔGo= –RTlnK
(R=8.314 J/K)
K= 7.25x10–12
First order
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