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Drill: Calculate the pH of 0.10 M H 2 Z in 0.50 M KHZ. K a1 = 2.0 x 10 -5 K a2 = 5.0 x 10 -9
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Transcript of Drill: Calculate the pH of 0.10 M H 2 Z in 0.50 M KHZ. K a1 = 2.0 x 10 -5 K a2 = 5.0 x 10 -9
Drill: Calculate the pH of 0.10 M H2Z in
0.50 M KHZ.Ka1 = 2.0 x 10-5
Ka2 = 5.0 x 10-9
Salt orHydrolysis Reactions
HydrolysisAny reaction in which water
is decomposed with all or part of its decomposition
portions combining with the products
Hydrolysis
Water is added to decompose something
Hydrolysis
MX + HOH
HX + MOH
Salts
Salts•Ionic compounds
that dissolve ~ 100 % in water
Salts of Acids•Salts of acids are
negative
(A-)
Salts of Bases•Salts of bases are
Positive
(M+ or B+)
Salt Solutions•When salts dissolve,
their ions can recombine with water
Salt Solutions•The salts of weak acids
can recombine with water producing basic
solutions
Salt Solutions•The salts of weak bases can recombine with water producing
acidic solutions
Salt Solutions
A- + H2O HA + OH-
B+ + H2O H+ + BOH
Drill: Calculate the salt/acid ratio of a
solution of benzoic acid & sodium benzoate at a
pH of 5.00.Ka HBz = 6.4 x 10-5
Salt or Hydrolysis Problems
Salt Problem•Calculate the pH of
a 0.20 M solution of NaBz
•Ka HBz = 6.4 x 10-5
Drill: Calculate the pH of a solution of
0.10 M NH3 in 0.20 NH4Cl.
Kb NH3 = 1.8 x 10-5
Salt or Hydrolysis Problems
Salt Problem•Calculate the pH of
a 0.20 M solution of KNO2
•Ka HNO2 = 7.1 x 10-4
Salt Problem•Calculate the pH of a
0.10 M solution of R-NH3Cl
•Kb R-NH2 = 2.5 x 10-5
Calculate the pH of a 0.18 M solution
of KC2H3O2
•Ka = 1.8 x 10-5
Drill: Calculate the salt to acid ratio required to make a buffer solution
with a pH of 4.495 using benzoic acid.Ka HBz = 6.4 x 10-5
Salt Applications
•Salts of strong acids & weak bases make
acidic solutions
Salt Applications
•Salts of strong bases & weak acids make
basic solutions
Salt Applications
•Salts of strong acids & strong bases make
neutral solutions
Predict Relative pH
•NaAc MnCl2
•KNO3 NH4Br
•KHSO4 NH4Ac
Predict Relative pH
•KAc NaCl
•KClO2 NH4Cl
•K2SO4 NaI
Anhydrides•Compounds without
water; that when added to water, form
other compounds
Acid Anhydrides
•Non-metal oxides that form acids when
added to water
Basic Anhydrides
•Metal oxides that form bases when added to water
Predict Relative pH
•Na2O SO2
•NO2 CO2
•CaO Al2O3
Calculate the pH of a 0.16 M solution
of KC7H5O2
•Ka = 6.4 x 10-5
•Calculate the pH of a solution of 0.0030 M KQ.
•Ka HQ = 3.0 x 10-5
Drill: Calculate the pH of a 0.72 M
NH4NO3 solution.Kb NH3 = 1.8 x 10-5
Are there any questions on
previous material?
A/B eq, Buffer & Salt
Hydrolysis Problem
Calculate [H3PO4], [H2PO4-1],
[HPO4-2], [PO4
-3], [K+], [H+], & pH of 1.0 M KH2PO4 in
0.50 M K2HPO4. Ka1 = 7.5 x 10-3
Ka2 = 6.2 x 10-8
Ka3 = 4.2 x 10-13
You need to make a buffer solution with its greatest
buffering capacity at pH ~ 5.4. In general terms,
describe what acid or base you would chose, & how
you would make the buffer.
11.2 g of KOH was added to 2.0 L of 0.075 M
H2CO3. Calculate the molarity of all ions
present in the solution.Ka1 = 4.4 x 10-7
Ka2 = 4.8 x 10-11
Drill: Calculate the pH of
0.10 M HF. Ka HF = 6.5 x 10-4
Test Review
Expect a straight acid/base
problem like the drill
Calculate the pH of 0.10 M HF in
0.20 M KF. Ka HF = 6.5 x 10-4
Calculate the pH of 0.10 M KF.
Ka HF = 6.5 x 10-4
Predict Relative pH
K2O MgO
ClO2 (NH4)2O
SO3 N2O3
Predict Relative pH
•KAc NaCl
•KClO2 NH4Cl
•K2SO4 NaI
Calculate the pH of 5.0 M KCN.
KaHCN= 5.0 x 10-10
Calculate pH of:0.20 M MOH in
0.50 M MCl
Kb = 5.0 x 10-5
Calculate pH of:0.20 M MCl
Kb = 5.0 x 10-5
Drill: Calculate the pH of
0.20 M KQ. Ka HQ = 8.0 x 10-5
Calculate pH of:
•0.20 M HNO2
•Ka = 2.0 x 10-4
Calculate pH of:•3.0 M HZ in
2.0 M KZ•Ka HZ = 3.0 x 10-5
Calculate pH of:
•0.20 M KR
•Ka HR = 2.0 x 10-5
Calculate pH of:
•2.0 M HQ
•Ka = 2.0 x 10-6
Calculate pH of:•0.60 M HZ in
0.90 M KZ•Ka HZ = 3.0 x 10-5
Calculate pH of:
•0.20 M KQ
•Ka HQ = 2.0 x 10-7
1.5 L of 0.25 M Ba(OH)2 was added to 1.0 L of 0.60 M
H2SO3. Calculate [H2SO3], [HSO3
-], [SO3-2], [H+], [OH-],
& pH of the solution.Ka1 = 1.7 x 10-2
Ka2 = 6.0 x 10-8
Review of Acid/Base descriptions and
Acid/Base, Buffer, & Salt Equilibria
Arhenius, Bronsted-Lowry, & Lewis Acids & Bases
Strong Acids
Strong Bases
Acid rxns
Base rxns
A/B Equilibrium Constants
KW, KA, KB, & pH
Calculate pH of:
•0.025 M HNO3
•0.020 M KOH
150 mL of 0.10 M KOH was added to 100.0 mL of 0.10 M H2CO3. Calculate [H2CO3],
[HCO3-], [CO3
-2], [H+], [OH-], & pH of the solution.
Ka1 = 4.4 x 10-7
Ka2 = 4.7 x 10-11
Calculate [H3A], [H2A-1], [HA-2], [A-3], [K+], [H+],
[OH-], & pH of 2.0 M KH2A. Ka1 = 4.0 x 10-3
Ka2 = 5.0 x 10-8
Ka3 = 2.5 x 10-13
The take-home portion of the test is due by
8:15 tomorrow