Transcript exam 2 practice test

REVIEW
1.
In the reaction H2CO3 + H2O  HCO3 + H3O+, the Brønsted acids are
A.
B.
C.
D.
E.
H2CO3 and H2O.
HCO3 and H2CO3.
H2O and H3O+.
H3O+ and H2CO3.
H2O and HCO3.
2.
Identify the conjugate base of HPO42 in the following
reaction:
HCO3 + HPO42  H2CO3 + PO43
A. H2O
B. HCO3 C. H2CO3
E. None of these.
•
D. PO43
3.
Identify the conjugate acid of SO42 in the following reaction:
CO32 + HSO4  HCO3 + SO42
A. CO32
B. HSO4
C. OH
D. H3O+
E. SO42
4.
Which one of the following statements about strong acids is true?
A.
All strong acids have H atoms bonded to electronegative oxygen
atoms.
B.
Strong acids are 100% ionized in water.
C.
The conjugate base of a strong acid is itself a strong base.
D.
Strong acids are very concentrated acids.
E.
Strong acids produce solutions with a higher pH than weak acids.
5.
Calculate the pH of a beer in which the hydrogen ion
concentration is 6.3  105 M.
A. 4.2
B. 4.8
C. 5.63
D. 9.8
E. 14.0
6.
Which one of the following is a buffer solution?
A.
B.
C.
D.
E.
0.40 M HCN and 0.10 KCN
0.20 M CH3COOH
1.0 M HNO3 and 1.0 M NaNO3
0.10 M KCN
0.50 M HCl and 0.10 NaCl
7
Assuming equal concentrations of conjugate base and acid, which one of
the following mixtures is suitable for making a buffer solution with an
optimum pH of 4.64.8?
A.
B.
C.
D.
E.
CH3COO2Na / CH3COOH (Ka = 1.8  105)
NH3 / NH4Cl (Ka = 5.6  1010)
NaOCl / HOCl (Ka = 3.2  108)
NaNO2 / HNO2 (Ka = 4.5  104)
NaCl / HCl
8
For which type of titration will the pH be basic at the equivalence point?
A.
B.
C.
D.
E.
Strong acid vs. strong base.
Strong acid vs. weak base.
Weak acid vs. strong base.
All of the above.
None of the above.
9.
A titration of an acid and base to the equivalence point results in a
noticeably acidic solution. It is likely this titration involves
A.
B.
C.
D.
a strong acid and a weak base.
a weak acid and a strong base.
a weak acid and a weak base (where Ka equals Kb).
a strong acid and a strong base.
10.
Methyl red is a common acid-base indicator. It has a Ka equal to 6.3 
106. Its un-ionized form is red and its anionic form is yellow. What color
would a methyl red solution have at pH = 7.8?
A. green
B. red
C. blue
D. yellow
E. violet
11.
For PbCl2 (Ksp = 2.4  10–4), will a precipitate of PbCl2 form when 0.10 L of
3.0  102
M Pb(NO3)2 is added to 400 mL of 9.0  102 M NaCl?
A.
B.
C.
D.
Yes, because Q > Ksp.
No, because Q < Ksp.
No, because Q = Ksp.
Yes, because Q < Ksp.
12.
Which of the following would decrease the Ksp for PbI2?
A.
Lowering the pH of the solution
B.
Adding a solution of Pb(NO3)2
C.
Adding a solution of KI
D.
None of the above—the Ksp of a compound is constant at
constant temperature.
13.
Examine the phase diagram for the substance Bogusium (Bo) and select the
correct statement.
A. Bo(s) has a lower density than Bo(l).
B. The triple point for Bo is at a higher temperature than the melting point for
Bo
C. Bo changes from a solid to a liquid as one follows the line from C to D.
D. Bo changes from a liquid to a gas as one follows the line from C to D
E. Point B represents the critical temperature and pressure for Bo
14.
Consider the following phase diagram and identify the process occurring as
one goes from point C to point D.
A.
B.
C.
D.
E.
increasing temperature with a phase change from solid to liquid
increasing temperature with a phase change from solid to vapor
increasing temperature with a phase change from liquid to vapor
increasing temperature with no phase change
increasing temperature beyond the critical point
15.
The pH of 1.00 x 10-2M solution of cyanic acid HOCN is 2.77 at 25oC.
Calculate the Ka for HOCN.
16.
A solution of formic acid (HCOOH, Ka = 1.8 x 10-4) has a pH of 2.70.
Calculate the initial concentration of formic acid in this solution.
17.
Calculate the pH of a 0.20 M C2H5NH2 solution (Kb = 5.6 x 10-4)
18.
Calculate the pH of a 0.20 M solution of Arsenic acid (H3AsO4), a triprotic
acid. Ka1 = 5 x 10-3, Ka2 = 8.0 x 10-8, Ka3 = 6.0 x 10-10.
19.
Sodium azide, NaN3 is sometimes added to water to kill bacteria. Calculate
the pH of a 0.01M solution of NaN3. The Ka value for HN3 is 1.9 x 10-5
20.
Carbonate buffers are important in regulating the pH of blood at 7.40. What
is the concentration ratio of H2CO3 to HCO3- in blood at pH 7.40?
Ka = 4.3 x 10 -7
21.
What volumes of 0.50 M HNO2 (Ka = 4 x 10-4) and 0.5M NaNO2 must be
mixed to prepare a solution buffered at pH = 3.55?
22.
Calculate the pH of a buffer solution containing 0.100M HC3H5O2 (propanoic
acid) and 0.100 M sodium propanoate (NaC3H5O2) Ka = 1.3 x 10 -5
Calculate the pH after 0.01 mol of NaOH is added to the above solution.
23.
Calculate the solubility of the following compounds in mol/L
a) Ag3PO4,
b) PBI2,
Ksp = 1.8 x 10-18
Ksp = 1.4 x 10-8
The solubilityof the ionic compound M2X3 having a molar mass of 288 g/mol
is 3.6 x 10-7 g/L. Calculate the Ksp of the compound.
24.
Calculate the molar solubility of Ca3(PO4)2 in 0.20M Na3PO4 solution. Ksp =
1.3 x 10-32
25.
A solution contains 1 x 10-5 M Na3PO4. What is the minimum concentration
of AgNO3 that would cause precipitation of solid Ag3PO4?
(Ksp = 1.8 x 10-18)