CHEM 161: Exam 2
Name:
Sections: 01 & 03
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Exam Percentage
(20) 1. For each of the following sets of reactants, write the formulas for the products (including
physical states) and balance the equation if the reaction occurs, or write “NR” for no reaction.
AgNO3(aq) 
a.
Zn(s)
+
b. 
C3H8O(l)
c. 
NaHCO3(s) +
d.
H2O(l) +
+

O2(g) 


HNO3(aq)
Mg(s) 
(16) 2. Predict the products for the following sets of reactants, then balance the equation and write the
net ionic equation (including physical states).
a.
H3PO4(aq) +
LiOH(aq)

net ionic equation:______________________________________________________________________
b.
Li2S(aq)
+
Fe(NO3)3(aq)

net ionic equation:______________________________________________________________________
CHEM 161 Exam 2
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(8)
3. Check all of the following that are oxidation-reduction (redox) reactions:
 a. 2 Li(s) + 2 H2O(l) H2(g) + 2 LiOH(aq)

 b. 2 Ni(HCO3)3(s) 
 3 CO2(g) + 3 H2O(g) + Ni2(CO3)3(s)
 c. 2 Li3PO4(aq) + 3 Cu(NO3)2(aq) Cu3(PO4)2(s) + 6 LiNO3(aq)
 d. 2 H2S(g) + 3 O2(g)  2 SO2(g) + 2 H2O(g)
4. Consider the following reaction: H2O(l) + HSO4(aq)
(2) a. H2O(l) is _________.
an Arrhenius acid
SO4(aq) + H3O+(aq)
a Bronsted-Lowry acid
(Circle all that apply.)
an Arrhenius base
a Bronsted-Lowry base
(4) b. Check all of the following statements that are true:
 i. HSO4 is both an Arrhenius acid and a a Bronsted-Lowry acid.
 ii. H2O is the conjugate base of H3O+
 iii. H2O is the conjugate acid of HSO4
 iv. SO4 is the conjugate base of HSO4.
5. Consider the following:
3 NO2(g) + H2O(l)  2 HNO3(aq) + NO(g)
Indicate the neutral element, ion, or element with its oxidation number in a compound that is
oxidized or reduced and the reactants that served as the oxidizing and the reducing agents below:
(6) a. The reactant oxidized is ___________________, and the oxidizing agent is _______________.
The reactant reduced is ___________________, and the reducing agent is _______________.
(3) b. The total number of electrons transferred in this reaction is _________.
6. Consider the following: Pb(s) + PbO2(s) + H2SO4(aq)  2 PbSO4(s) + 2 H2O(l)
Indicate the neutral element, ion, or element with its oxidation number in a compound that is
oxidized or reduced and the reactants that served as the oxidizing and the reducing agents below:
(6) a. The reactant oxidized is ___________________, and the oxidizing agent is _______________.
The reactant reduced is ___________________, and the reducing agent is _______________.
(3) b. The total number of electrons transferred in this reaction is _________.
CHEM 161 Exam 2
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(5) 7. Check all of the following statements that are true:
 a. Fewer air molecules are present at the top of Mt. Rainier than in air at sea level.
 b. Two gases confined to the same container will eventually form a uniform gas mixture.
 c. Gas pressure remains constant even if a sample of helium in a 2.00 L container is heated.
 d. Some ionic compounds exist as gases at room temperature.
 e. The flow of wine out of an airtight barrel eventually decreases because of the suction
resulting from the vacuum produced.
(9) 8. Consider the following: Table A: Observations of Experimental Results
Na2SO4 (aq)
Na2CO3(aq)
NaOH(aq)
NaCl(aq)
AgNO3 (aq)
small white
flakes
yellow-gray solid
powdery brown
solid
powdery white
solid
Zn(NO3)2(aq)
NR
filmy white solid
filmy white solid
NR
Sr(NO3)2(aq)
milky white solid
filmy white solid
NR
NR
NR
bubbles
heat
NR
HNO3(aq)
During one experiment a student collected the results shown above. The student was then given an
solution of a soluble ionic compound consisting of only one each of the following cations and anions:
Ag+, Zn2+, Sr2+, H+, or Na+ and SO42, CO32, OH, Cl, or NO3.
The student then tested a fresh sample of her unknown with sodium carbonate, which resulted in a white
solid. Next, the student tested a fresh sample of her unknown with silver nitrate, which resulted in no
precipitate. Finally, the student tested a fresh sample of her unknown with sodium hydroxide which
resulted in no precipitate.
Identify the cation and anion in the student’s unknown solution: cation=_______ and anion=_______
For the problems below, SHOW ALL WORK and give the answer with the correct units and the
correct number of significant figures to receive full credit. Circle your answer.
(9) 9. A small bubble occupying 0.150 mL rises from the bottom of a lake, where the temperature and
pressure are 277.15K and 4905 torr. The bubble rises to the water’s surface, where the temperature
and pressure are 23.00˚C and 0.9985 atm. Calculate the bubble’s final volume.
CHEM 161 Exam 2
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For the problems below, SHOW ALL WORK and give the answer with the correct units and the
correct number of significant figures to receive full credit. Circle your answer for each.
10. Consider the following reaction: Cu(s) + 4 HNO3(aq)  Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l)
(13) a. Calculate the mass of nitrogen dioxide gas produced when 1.750 g of copper react with
50.00 mL of 3.00M nitric acid.
mass of nitrogen dioxide produced = ______________________________
(7)
b. Calculate the molar concentration of hydrogen ions in solution after the reaction in part a
above is complete.
(8)
c. Calculate the mass percent concentration of copper(II) ions in solution after the reaction in
part a above is complete if the density of the remaining solution is 1.01 g/mL.
CHEM 161 Exam 2
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For the problem below, SHOW ALL WORK and give the answer with the correct units and the
correct number of significant figures to receive full credit. Circle your answer.
Extra Credit (6 points): Consider the following reaction:
Cu(s) + 4 HNO3(aq)

Cu(NO3)2(aq) + 2 NO2(g) + 2 H2O(l)
brown gas
A sample of copper is reacted with excess nitric acid to produce the brown nitrogen dioxide gas. Drops of
sodium hydroxide are then added to the resulting solution to neutralize the excess acid and produce
copper(II) hydroxide precipitate. If 10.00 mL of 6.00M nitric acid were used, and 15.35 mL of 2.00M
sodium hydroxide were required to neutralize the excess acid, calculate the mass for the original copper
sample that was reacted.
CHEM 161 Exam 2
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