Directions:
Mark the letter of the correct answer on your answer sheet with medium
lead (No. 2) pencil. You may use your exam sheet for scratch paper. You
may keep your exam paper. Each question is worth 6 points for a total of
120 points possible. No additional penalty for guessing. Note that some
questions may have more than one correct answer. You will be given partial
credit in some instances. Your exam will be graded on the basis of 100
points (i.e. 20 bonus points built in).
Consider the following reactions
for the next series of questions (Problems 1-5). More than one letter may
apply per question.Make sure to
mark them all on the same line.If
none apply, leave blank.
a.2H2O2
(g) ®
2H2O(l)
+O2 (g)
b. HBr(aq) + Na2CO3(aq) ®NaBr(aq) +H2O(l)+CO2(g)
c. 2KNO2(s) + O2(g)® 2KNO3(s)
d. 2KCl(aq) + Hg2(NO3)2(aq)®
e. 2Al(NO3)3 (aq) + 3H2SO4(aq) ®
1.
Which of the above is(are) a redox reaction?a,c
2.Which
of the above is(are) a combination reaction?c
3.Which
of the above is(are) a decomposition reaction? a,b
4.Choosing from only the aqueous reactions, which of the above will not give a precipitate?e,b
5.Which
of the above is(are) a combustion reaction?c
6.What
would be the oxidation state of chlorine in the combination product that
results from adding Cl2O7 to water to generate perchloric
acid?
a.–1
b.0
c.+1
d.+5
#e.+7
7.The
reaction in Problem 6 is only a redox reaction.
a.True
#b.False,
it’s only a combination reaction.
c.False,
it’s a redox reaction and a combination reaction.
8.If
the perchloric acid reacted with a substance that as a result produced
chlorine gas as one of the products as well as a product that had more
oxygen in it than when it began, it could be said that the chlorine in
perchloric acid was ______ and therefore perchloric acid was the________
agent.
a.oxidized,
oxidizing
#b.reduced,
oxidizing
c.reduced,
reducing
d.oxidized,
reducing (duplicated the correct answer in original exam)
e.not
reduced, not the reducing agent since this is not a redox reaction.
9.
Which of the following compound(s) is(are) a strong electrolyte?
a.
C2H6O2 (l)
(ethylene
glycol—antifreeze additive)
b.N2O(g)
#c.Ba(OH)2
(aq)
#d.HClO4
(aq)
e.
CH3COOH (aq) (acetic acid)
10.
Which of the following is(are) basic oxide(s)?
#a.
Na2O
b.
CO2
#c.
CaO
d.
P2O5
e.
Cl2O7
11.What
is the coefficient of H2O when the following equation is properly
balanced with smallest set of whole numbers?
______
Al4C3 + ______ H2O ®
______ Al(OH)3+ ______
CH4
a.
3
b.
4
c.
6
#d.
12
e.
24
12.The
reaction in Problem 11 would produce a precipitate
#a.True
b.False
13.The
oxidation state of carbon in Al4C3 is +4.
a.True
b.False,
it’s +2
c.False,
it’s –3
#d.False,
it’s –4
14.
Ammonia reacts with dioxygen to form nitric oxide and water vapor according
to the unbalanced equation below.How
many moles of H2O are formed when 6.0 moles of NH3
react according to the equation?
a.
2 b.
3 c.
6 #d.
9 e.
12 15.The
reaction in Problem 14 above represents a (mark all that apply) #a.redox
reaction b.combination
reaction c.displacement
reaction #d.combustion
reaction e.acid-base
reaction 16.Calculate
the mass of pyrite, FeS2, formed when 13.42 g of Fe are allowed
to react with 8.50 g of S8.Note
the equation is unbalanced. (molar masses:Fe-55.8;
S-32.1) Fe(s)+S8(s)®FeS2(s) #a.
15.9 g b.
87.9 g c.
26.0 g d.
14.8 g e.
1.91 x 10-3 g 17.The
theoretical yield of a reaction is 34.8 g, and the amount of product isolated
is 24.6 g.The % yield is:
a.
37.6% #b.
70.7% c.
89.0% d.
10.0% e.
43.9% 18.A
solution was made by dissolving 25.00 g of NaOH in 250.0 mL of water.What
is the molarity?
a.0.1000M
#b.2.500
M
c.4.000
M
d.0.8965
M
e.1.250
M
19.Assuming
the above solution in Problem 18 had a density of 1.10 g/mL, what would
be the % by weight of NaOH?
a.5.00%
b.40.0%
c.2.27%
#d.9.09%
e.3.90%
20.Solid
Ca(OH)2 was added to 50.00 mL of 2.000 M HCl.The
resultant molarity of HCl dropped to 0.450M.How
many grams of Ca(OH)2 were added?(molar
masses :Ca – 40.1; H – 1.0; O –
16.0; Cl – 35.5).
#a.2.87
g
b.3.57
g
c.5.74g
d.1.00
g
e.none
of the above