EXAM 2 Flashcards
Consider two solutions, solution A: 1.0 M hydrofluoric acid (HF) and solution B: a mixture of 1.0 M HF and 1.0 M NaF. If a strong base is added to both of these solutions, what will the result be?
Solution A will increase in pH and Solution B’s pH won’t change very much.
Identify the correct statement about an acid–base buffer solution.
All:
A buffer solution resists changes in its pH when an acid or base is added to it.
It can be prepared by combining a weak acid with a salt of its conjugate base.
It can be prepared by combining a weak base with its conjugate acid.
The pH of a buffer solution does not change when the solution is diluted.
Which of these can be mixed together in water to produce a buffer solution?
HClO4 and NaClO4
HNO3 and NaNO3
H2SO4 and NaHSO4
H3PO4 and NaH2PO4
HCl and NaCl
H3PO4 and NaH2PO4
Which of these can be mixed together in water to produce a buffer solution?
NH3 and HCl
HF and KF
HClO3 and NaClO3
HCN and NaOH
ALL!
Which of these would make the best buffer? (Ac = acetate)
a solution of hydrochloric acid and sodium chloride, HCl and NaCl
a solution of acetic acid and ammonia, NaAc and NH3
a solution of acetic acid and ammonium chloride, HAc and NH4Cl
a solution of sodium acetate and ammonium chloride, NaAc and NH4Cl
a solution of ammonia and ammonium chloride, NH3 and NH4Cl
a solution of ammonia and ammonium chloride, NH3 and NH4Cl
Which of the following is a buffer system? Solutions contain roughly equal amounts of each substance
fluoride ion and hydrofluoric acid
bromide ion and hydrobromic acid
phosphide ion and hydrogen phosphate ion
carbonate ion and carbonic acid
phosphoric acid and phosphate ion
fluoride ion and hydrofluoric acid
Which would be the best choice for preparing a buffer with a pH = 8.0?
a solution of formic acid and sodium formate, Ka= 1.8 × 10-4
a solution of acetic acid and sodium acetate, Ka= 1.8 × 10-5
a solution of hypochlorous acid and sodium hypochlorite, Ka= 3.5 × 10-8
a solution of boric acid and sodium borate, Ka= 5.8 × 10-10
All of these solutions would be equally good choices for making this buffer.
a solution of hypochlorous acid and sodium hypochlorite, Ka= 3.5 × 10-8
Which would be the best choice for preparing a buffer with a pH = 3.5?
a solution of formic acid and sodium formate, Ka= 1.8 × 10-4
a solution of acetic acid and sodium acetate, Ka= 1.8 × 10-5
a solution of hypochlorous acid and sodium hypochlorite, Ka= 3.5 × 10-8
a solution of boric acid and sodium borate, Ka= 5.8 × 10-10
All of these solutions would be equally good choices for making this buffer
a solution of formic acid and sodium formate, Ka= 1.8 × 10-4
What is the pH of a buffer solution where [HA] = [A-]?
pH = 1
pH =Ka
pH = pKa
pH = pOH
pH = 7.0
pH = pKa
The pKaof a weak acid was determined by measuring the pH of a solution containing the weak acid at 0.40 M and its conjugate base at 0.60 M. The measured pH was 7.8. What is the pKa of the weak acid?
8.0
7.8
7.6
7.0
7.4
7.6
The pKaof a weak acid was determined to be 3.39 by measuring the pH of a solution containing the weak acid at 0.20 M and its conjugate base. The measured pH was 3.27. What was the concentration of the conjugate base?
0.26 M
0.15 M
0.20 M
0.050 M
0.35 M
0.15M
What is the pHof a solution containing 0.30 M of lactic acid and 0.50 M of lactate ion (Ka for lactic acid = 1.38 ×10-4)?
9.92
10.36
3.86
4.08
3.64
4.08
How many moles of sodium acetate must be added to 500. mL of a 0.25 M acetic acid solution to produce a buffer with a pH of 4.94? The pKa of acetic acid is 4.74. (You can neglect the change in volume when sodium acetate dissolves in the acetic acid solution.)
0.011 moles
0.021 moles
0.125 moles
0.198 moles
0.206 moles
0.198 moles
What are the characteristics of a pH indicator? A pH indicator
is a weak acid.
has different characteristic colors in protonated and unprotonated forms.
changes color when the pH is near its pKa.
none of these answers
all of these
all of these
Acid–base indicators need to have very intense colors so a very low concentration is visible. Could there be a problem in using too much indicator?
No, the colors would just be darker.
No, indicators are inert.
Yes, more indicator requires more extreme pH values to change color.
Yes, the indicator could affect the acid–base chemistry being measured.
No, the colors would just be sharper.
Yes, the indicator could affect the acid–base chemistry being measured.
In a titration of monoprotic acids and bases, there is a large change in pH
at the point where pH = pKa of the acid.
when the volume of acid is exactly equal to the volume of base.
when the concentration of acid is exactly equal to the concentration of base.
when the number of moles of acid is exactly equal to the number of moles of base.
at the point where pH = pKb of the base.
when the number of moles of acid is exactly equal to the number of moles of base.
Halfway to the equivalence point in a titration curve of a weak acid with a strong base,
nothing is happening yet.
the pH = pKa of the weak acid.
pH = 3.5 exactly.
pH = pKa of the indicator.
the pH has not yet changed.
the pH = pKa of the weak acid.
At what point in the following titration curve for a weak acid being titrated with a strong base is the pH equal to the pKa of the acid? The x-axis scale goes from 0.0 mL to 20.0 mL. The sharp rise is at 10.0 mL.
0.0 mL
5.0 mL
9.0 mL
10.0 mL
18.0 mL
5.0mL
A Lewis acid is
a proton donor.
a proton acceptor.
an electron-pair donor.
an electron-pair acceptor.
never viewed also as a Brønsted–Lowry acid.
an electron-pair acceptor
A Lewis base is
an electron-pair acceptor.
an electron-pair donor.
a proton donor.
a proton acceptor.
never viewed also as a Brønsted–Lowry base.
an electron-pair donor
A Lewis base is any species capable of ________ an electron pair.
accepting
donating
creating
neutralizing
gaining
donating
A Lewis acid is any species capable of ________ an electron pair.
accepting
donating
creating
neutralizing
losing
accepting
In this reaction, which species is the Lewis acid?
Cu^2+ + NH3-> Cu(NH3)^2+
Cu2+
NH3
[Cu(NH3)]2+
None of these is an acid.
All of these are acids
Cu2+
Which species is a Lewis base?
H3O+
Na+
BF3
P(CH3)3
NH4+
P(CH3)3
Which species is a Lewis acid?
Cl2
NH3
F-
P(CH3)3
Al3+
Al3+
Which statement about acids and bases is correct?
A Lewis base is an electron-pair donor; a Lewis acid is an electron-pair acceptor.
A Brønsted–Lowry base is a proton acceptor; a Brønsted–Lowry acid is a proton donor.
A Lewis base can accept a proton from a Brønsted–Lowry acid.
Coordinate covalent bonds in transition metal compounds are formed when a Lewis base reacts with a Lewis acid.
All statements are correct.
ALL
Which compound contains a coordinate covalent bond?
Cl2
NH3
H2C=CH2
Co(H2O)6^2+
CH4
Co(H2O)6^2+
Which compound contains a coordinate covalent bond?
PF3
H3NBF3
HCOOH
AlCl3
O2
H3NBF3
The bond between a metal cation and a ligand can best be described as
an ionic bond.
a covalent bond.
a coordinate covalent bond.
a polar covalent bond.
a bidentate bond.
a coordinate covalent bond.
The bonds between the zinc ion and the nitrogen atoms in the complex Zn(NH3)42+ are best described as
ionic.
covalent.
coordinate covalent.
polar covalent.
d-electron bonds.
coordinate covalent.
A ligand is any ________ forming a coordinate bond to a metal cation.
Lewis acid
ion
Lewis base
organic compound
species
Lewis base
Which species is least likely to function as a ligand in a transition metal complex ion?
NH4+
NH3
Cl-
H2O
OH-
NH4+
Which species is most likely to function as a ligand in a transition metal complex ion?
BF4+
AlBr3
P(CH3)3
Ca2+
BeCl2
P(CH3)3
Lead poisoning used to be treated by injections of ethylenediaminetetraacetic acid, EDTA. If the concentration of EDTA in the blood of a patient is 3.0 × 10-9M and the formation constant for Pb(EDTA)2- is 2.0 × 1018, what is the concentration ratio of free toxic Pb2+ to lead–EDTA complex in the blood?
2.0 × 10-11
1.7 × 10-10
2.0 × 10-9
5.0 × 10-19
3.0 × 10-9
1.7 × 10-10
What is the molar concentration of Ag+(aq) in a 1.00 M solution of Ag(NH3)2+ with no excess ammonia, given the following information?
Kf= 1.70 × 107 for Ag(NH3)2+
2.45 × 10-3M
3.09 × 10-3M
2.42 × 10-4M
1.47 × 10-8M
1.70 × 10-8M
2.45 × 10-3M
Hydrated transition metal ions produce solutions that are
acidic.
basic.
neutral.
strongly basic.
strongly acidic.
acidic.
Many metal cations produce aqueous solutions that have a pH different from 7. Which statement about this phenomenon are correct?
For a given metal, the cation with the higher oxidation number will produce more acidic solution, for example, Fe3+(aq) is more acidic than Fe2+(aq).
The Lewis acidity of the cation is a good measure of its ability to produce an acidic solution.
Small highly charged main group metal cations, such as Al3+, produce acidic aqueous solutions.
Alkali metal cations, such as Na+ and K+, have a negligible effect on the pH of a solution.
All statements are correct.
ALL
Aqueous solutions of many metal cations have a pH different from 7. Which statement about these cations are correct?
Alkali metal cations such as Na+ and K+ have a negligible effect on the pH.
Small and highly charged main group metals such as Al3+ produce acidic aqueous solutions.
For transition metal cations, the cation with the higher oxidation state produces more acidic solution; for example, Fe3+(aq) is more acidic than Fe2+(aq).
The Lewis acidity of a metal cation is a good measure of its ability to activate a water molecule to lose a proton and produce a hydronium ion.
All statements are correct.
ALL
Which of the following compounds forms an acidic solution when dissolved in water?
CaCl2
MgCl2
NaCl
FeCl2
All of these form an acidic solution when dissolved in water.
FeCl2
Calculate the pH of a 1.5 M solution hexaaquairon (III). The Ka of Fe3+ is 3.0 10–3.
2.52
0.85
1.18
7.00
2.35
1.18
Calculate the pH of a 0.75 M solution of AlCl3. The Ka of Al3+ is 1.0 10–5.
2.56
7.00
5.00
5.12
0.13
2.56
Calculate the solubility of MgF2 in water if the Ksp for the compound is 6.40 × 10-9.
2.13 × 10-9M
1.86 × 10-3M
1.17 × 10-3M
1.47 × 10-3M
3.25 × 10-5M
1.17 × 10-3M
Calculate the Ksp for Li3PO4 if, at equilibrium, the concentration of PO43- ion is 3.30 × 10-3M.
3.2 × 10-9
3.6 × 10-10
1.2 × 10-10
5.7 × 10-2
8.3 × 10-4
3.2 × 10-9
Which of the following represents the correct Ksp expression for the reaction shown?
Al2(SO4)3(s) 2Al3+(aq) + 3SO42-(aq)
1) [Al3+]2[SO42-]3
2) 2[Al3+]+ 3[SO42-]
3) [Al3+][SO42-]
1) [Al3+]2[SO42-]3
Lead pipes were used at one time for delivering drinking water. What is the maximum possible concentration of lead in this water if it comes from lead(II) hydroxide (Ksp= 2.8 × 10-16) dissolving from the surface of the pipes? Note the U.S. Environmental Protection Agency’s limit on lead in drinking water is 7.2 × 10-8M.
4.1 × 10-6M
1.6 × 10-8M
6.5 × 10-6M
5.1 × 10-6M
8.3 × 10-9M
4.1 × 10-6M
The solubility of PbI2 is 0.756 g per 100 mL of solution at 20°C. Determine the value of the solubility product constant for this compound at 20°C. Lead(II) iodide does not react with water.
4.9 × 10-4
3.3 × 10-4
1.8 × 10-5
1.2 × 10-6
4.3 × 10-6
1.8 × 10-5
The solubility product for an insoluble salt with the formula MX3 is written as ________, where s is the molar solubility.
Ksp=s^2
Ksp= 4s^3
Ksp= 27s^4
Ksp= 3s^3
Ksp= 3s^4
Ksp= 27s^4
The solubility product for an insoluble salt with the formula M2X3 is written as ________, where s is the molar solubility.
Ksp= 108s^5
Ksp= 6s^5
Ksp= 18s^5
Ksp=s^5
Ksp= 56s^5
Ksp= 108s^5
The solubility product for an insoluble salt with the formula MX2 is written as ________, where s is the molar solubility.
Ksp=s^2
Ksp= 4s^3
Ksp= 4s^2
Ksp= 2s^3
Ksp= 2s^2
Ksp= 4s^3
The solubility product for an insoluble salt with the formula MX4 is written as ________, where s is the molar solubility.
Ksp= 128s5
Ksp= 64s5
Ksp= 16s5
Ksp= 256s5
Ksp= 4s5
Ksp= 256s5
What is the solubility of barium sulfate in a solution containing 0.050 M sodium sulfate? The Ksp value for barium sulfate is 1.1 × 10-10.
7.4 × 10-6M
5.5 × 10-11M
1.0 × 10-5M
2.2 × 10-9M
1.1 × 10-10M
2.2 × 10-9M
What is the solubility of silver iodide in a solution containing 0.20 M sodium iodide? The Ksp value for silver iodide is 1.5 × 10-16.
7.5 × 10-16M
1.2 × 10-8M
3.0 × 10-17M
0.20 M
2.1 × 10-10M
7.5 × 10-16M
As the pH decreases, the solubility of ________ would increase.
lead(II) chloride
silver(I) iodide
calcium carbonate
mercury(I) bromide
silver(I) chloride
calcium carbonate
As the pH increases, the solubility of ________ would increase.
lead(II) hydroxide
barium chloride
sodium hydroxide
magnesium sulfide
aluminum chloride
aluminum chloride
Which compound’s solubility is independent of pH?
Mg(OH)2
PbS
AgI
Na2O
PbCl2
AgI
Which salt would you predict to have a solubility in water that increases as the pH decreases?
calcium fluoride
silver chloride
silver iodide
mercury(I) bromide
lead(II) chloride
calcium fluoride
Which sodium halide salt, if any, would you predict to have a solubility in water that increases as the pH decreases?
sodium fluoride
sodium chloride
sodium bromide
sodium iodide
The solubility of sodium halide salts should not depend on the pH.
sodium fluoride
What is the oxidation state of the nickel atom in the Ni(CN)53- complex ion?
+0
+1
+2
+3
+4
+2
What is the oxidation state of the gold atom in the AuCl4- complex ion?
+0
+1
+2
+3
+4
+3
How many ions are formed when [Co(NH3)5Cl]Cl2 dissolves in water?
1
2
3
4
5
3
How many ions are formed when Na[Co(CO)4] dissolves in water?
1
2
3
5
6
2
In K4[Fe(CN)6], the counter ion is ________, and in [Co(NH3)4Cl2]NO3, the counter ion is ________.
CN-; NO3-
K+; NO3-
CN-; Cl-
K+; Cl-
Fe2+; Co3+
K+; NO3-
For the coordination compound K3[Fe(CN)6], identify, in order, the charge on the complex ion, the oxidation state of the metal, and the coordination number of the metal.
3+, 3-, 6+
0, 0, 6+
3-, 3+, 3+
3-, 3+, 6+
None of these choices are correct
3-, 3+, 6+
For the coordination compound [Co(NH3)4Cl2]NO3, identify, in order, the charge on the complex ion, the oxidation state of the metal, and the coordination number of the metal.
1+, 1+, 6
0, 0, 4
3+, 3+, 4
1+, 3+, 6
None of these choices are correct.
1+, 3+, 6
For the coordination compound [Cr(NH3)3(H2O)3]Cl3, identify, in order, the charge on the complex ion, the oxidation state of the metal, and the coordination number of the metal.
3+, 1+, 6
0, 0, 6
3+, 3+, 4
1+, 3+, 6
3+, 3+, 6
3+, 3+, 6
The coordination number for nickel in the compound Na3[Ni(CN)5] is
2
3
6
4
5
5
The coordination number for platinum in the compound [Pt(NH3)4]Cl2 is
2
3
6
4
5
4
The coordination number for copper in the compound K2[CuCl4] is
6
4
3
2
5
4
The coordination number around the Ni ion in [Co(NH3)6][Ni(CN)5] is
2
1
6
5
7
5
What do you predict for the geometry of Ti(H2O)6^3+?
octahedral
tetrahedral
square planar
trigonal bipyramidal
square pyramidal
octahedral
What is the shape of the complex ion CoF63-?
square pyramidal
octahedral
tetrahedral
trigonal bipyramidal
square planar
octahedral
What is the shape of Zn(OH)4^2-?
triangular pyramid
tetrahedral
octahedral
square pyramid
T-shaped
tetrahedral
Which ligand is correctly named?
H2O, hydro
NH3, ammine
CN-, cyanate
CO, carboxyl
OH-, hydroxy
NH3, ammine
The correct name for the complex ion [Mo(CN)6]4- is
hexacyanomolybdenum(II).
hexacyanomolybdenite(III).
hexacyanomolybdenate(II).
molybdenum(0) hexacyanide.
molybdenum(VIII) cyanide.
hexacyanomolybdenate(II).
The correct name for the complex ion[Cr(H2O)4Cl2]+ is
tetraaquadichlorochromium(II).
tetraaquadichlorochromium(III).
dichlorotetraaquochromium(II).
tetraaquadichlorochromate(III).
tetraaquadichlorochromium.
tetraaquadichlorochromium(III).
The correct formula for the complex ion tetrabromocuprate(II) is
[CuBr4]2-.
[CuBr4]2+.
CuBr4.
[CoBr4]2+.
[CoBr4]2-.
[CuBr4]2-.
What is the chemical formula of amminetrichloroplatinate(II)?
[Pt2(NH3)Cl3] -
[Pt(NH3)3Cl] -
[Pt(NH3)Cl3]2-
[Pt(NH3)Cl3] +
[Pt(NH3)Cl3] -
[Pt(NH3)Cl3] -
The correct name for K2[CuCl4] is
potassium copper chloride.
potassium tetrachlorocuprate(II).
dipotassium chlorocuprate(II).
potassium tetrachlorocopper(II).
dipotassium tetrachlorocopper(II).
potassium tetrachlorocuprate(II).
The correct name for [Co(NH3)5Cl]Cl2 is
pentaamminechlorocobalt(III) chloride.
pentaamminechlorocobalt(II) chloride.
chloropentaamminecobalt(III) chloride.
pentaamminechlorocobaltate(III) chloride.
pentaamminedichlorocobalt(III).
pentaamminechlorocobalt(III) chloride.
EDTA is an example of a _________ ligand.
tridentate
hexadentate
tetradentate
pentadentate
hydrocarbon
hexadentate
Which of these is a chelation agent?
EDTA
Cl-
NH2
SCN-
CN-
EDTA
