Download College Chemistry I PHS 1025 Fall 2012 Practice Exam 3A

College Chemistry I PHS 1025 Fall 2012 Practice Exam 3A
Name___________________________________
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Balance the chemical equation given below, and determine the number of grams of MgO needed 1) _______
to produce 15.0 g of Fe2O3.
___ MgO(s) + ___ Fe(s) → ___ Fe2O3(s) + ___ Mg(s)
A) 11.4 g
B) 1.26 g
C) 0.0877 g
D) 3.78 g
2) Given that ΔH°= -311 kJ for the hydrogenation of acetylene, C2H2:
2) _______
H C C H(g) + 2 H2(g) → CH3-CH3(g)
and the following bond dissociation energies, estimate a value for the C-to-C triple bond
dissociation energy.
A) 807 kJ/mol
B) 833 kJ/mol
C) 397 kJ/mol
D) 1050 kJ/mol
3) Isoeugenol is the compound which gives the characteristic odor to nutmeg and contains carbon,
hydrogen, and oxygen. If a 0.500 g sample of isoeugenol is combusted it gives 1.341 g of CO 2
3) _______
and 0.329 g of H2O. Isoeugenol has a molecular weight of 164 g/mol. What is the molecular
formula of isoeugenol?
A) C10H12O2
B) C8H4O4
C) C2HO
D) C5H6O
4) In the reaction AgNO3(aq) + HI(aq) → AgI(s) + HNO3(aq) the spectator ions are
A) Ag+ and I–
B) H+ and I–
C) H+ and NO3–
4) _______
D) Ag+ and NO3–
5) According to the balanced equation shown below, 1.00 mole of oxalic acid, H 2C2O4, reacts with
________ moles of permanganate ion, MnO4-.
5) _______
5 H2C2O4(aq) + 2 MnO4-(aq) + 6 H+(aq) → 10 CO2(g) + 2 Mn2+(aq) + 8 H2O(l)
A) 0.400
B) 2.25
C) 1.00
D) 2.00
6) When 50.0 mL of 0.400 M Ca(NO3)2 is added to 50.0 mL of 0.800 M NaF, CaF2 precipitates, as
6) _______
shown in the net ionic equation below. The initial temperature of both solutions is 25.00°C.
Assuming that the reaction goes to completion, and that the resulting solution has a mass of
100.00 g and a specific heat of
Ca2+(aq) + 2 F-(aq) → CaF2(s)
A) 24.45°C
B) 26.10°C
calculate the final temperature of the solution.
ΔH° = -11.5 kJ
C) 26.65°C
D) 25.55°C
7) What is the oxidation number of the chromium atom in K2Cr2O7?
A) +7
B) -2
C) +6
7) _______
D) +2
8) Which species functions as the oxidizing agent in the following reduction-oxidation reaction:
A) Zn2+(aq)
B) Cu2+(aq)
C) Cu(s)
D) Zn(s)
8) _______
9) Given: S (s) + O2 (g) → SO2 (g)
2 SO3 (g) → 2 SO2 (g) + O2 (g)
ΔH° = -296.1 kJ
9) _______
ΔH° = 198.2 kJ
Find ΔH° for : 2 S(s) + 3 O2(g) → 2 SO3(g)
A) -97.9 kJ
B) -790.4 kJ
C) +97.9 kJ
D) -394.0 kJ
10) Find ΔH for C3H8 (g) + 6 H2O (g) → 3 CO2 (g) + 10 H2
given
10) ______
C3H8 (g) + 3 H2O (g) → 3 CO (g) + 7 H2 (g)
ΔH = 499 kJ
CO (g) + H2O (g) → CO2 (g) + H2 (g)
ΔH = -41 kJ
A) 376 kJ
B) 540 kJ
C) 458 kJ
D) 622 kJ
Reactant R reacts with reactant S in two steps to yield product Z.
11) The product, Z, is represented by
A) arrow A.
B) line D.
11) ______
C) line E.
D) line F.
12) Step (1) in the reaction is represented by
A) arrow A.
B) arrow B.
C) arrow C.
D) line E.
13) The intermediate, T, + S is represented by
A) arrow C.
B) line D.
C) line E.
D) line F.
14) The reactants, R + 2 S, are represented by
A) arrow B.
B) line D.
C) line E.
D) line F.
15) Step (2) in the reaction is represented by
A) arrow A.
B) arrow B.
C) arrow C.
D) line E.
16) The net reaction is represented by
A) arrow A.
B) arrow B.
C) arrow C.
D) line F.
12) ______
13) ______
14) ______
15) ______
16) ______
17) How many milliliters of 0.260 M Na2S are needed to react with 25.00 mL of 0.315 M AgNO3?
Na2S(aq) + 2 AgNO3(aq) → 2 NaNO3(aq) + Ag2S(s)
A) 60.6 mL
B) 41.3 mL
C) 15.1 mL
D) 30.3 mL
18) What is the molar concentration of sodium ions in a 0.350 M Na 3PO4 solution?
A) 1.40 M
B) 0.117 M
C) 1.05 M
17) ______
D) 0.350 M
18) ______
19) Which is expected to have the largest carbon-oxygen bond dissociation energy?
A) CO32–
B) CO2
C) CO
D) HCO2H
19) ______
20) Combustion analysis of a 0.675 g sample of an unknown compound that contains only carbon,
hydrogen, and oxygen gives 0.627 g of CO2 and 1.534 g of H2O. The molecular mass of the
20) ______
unknown is
A) C3H6O.
C) unable to be determined from this data.
B) C6H12O2.
D) C9H18O3.
21) If the percent yield for the following reaction is 65.0%, how many grams of KClO3 are needed to
21) ______
produce 42.0 g of O2?
2 KClO3(s) → 2 KCl(s) + 3 O2(g)
A) 69.7 g
B) 165 g
C) 371 g
D) 107 g
22) The heat of combustion per mole for acetylene, C2H2(g), is -1299.5 kJ/mol. Assuming that the
22) ______
combustion products are CO2(g) and H2O(l), and given that the enthalpy of formation is -393.5
kJ/mol for CO2(g) and -285.8 kJ/mol for H2O(l), find the enthalpy of formation of C2H2(g).
A) -846.1 kJ/mol
B) -620.2 kJ/mol
C) +226.7 kJ/mol
D) -226.7 kJ/mol
23) At 25°C the heat of fusion of aluminum is 10.6 kJ/mol and the heat of sublimation is 326.4 kJ/mol.
What is the heat of vaporization of aluminum at 25°C?
A) 337.0 kJ/mol
B) 168.5 kJ/mol
C) 315.8 kJ/mol
D) 158.2 kJ/mol
23) ______
24) Calculate the enthalpy of combustion per mole for C6H12O6. Assume that the combustion
24) ______
products are CO2(g) and H2O(l).
A) -2816 kJ/mol
B) -5336 kJ/mol
C) 580.7 kJ/mol
D) -1939 kJ/mol
25) Balance the chemical equation given below, and calculate the volume of nitrogen monoxide gas
produced when 8.00 g of ammonia is reacted with 12.0 g of oxygen at 25°C? The density of
nitrogen monoxide at 25°C is 1.23 g/L.
___ NH3(g) + ___ O2(g) → ___ NO(g) + ___ H2O(l)
A) 18.8 L
B) 7.32 L
C) 11.1 L
25) ______
D) 11.5 L
26) Use the given standard enthalpies of formation to calculate ΔH° for the following reaction
3 Fe2O3(s) + CO(g) → 2 Fe3O4(s) + CO2(g).
26)
______
A) -5213.4 kJ
B) -47.2 kJ
C) +47.2 kJ
D) -577.2 kJ
27) Which of CH4(g), C2H2(g), and CH3OH(l) provides the most energy per gram upon combustion
and which provides the least?
CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l)
27) ______
ΔH° = -890 kJ
2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(l)
ΔH° = -2599 kJ
2 CH3OH(l) + 3 O2(g) → 2 CO2(g) + 4 H2O(l)
ΔH° = -1453 kJ
A) CH4 provides the most energy per gram and CH3OH the least.
B) C2H2 provides the most energy per gram and CH4 the least.
C) CH4 provides the most energy per gram and C2H2 the least.
D) C2H2 provides the most energy per gram and CH3OH the least.
28) Write a balanced net ionic equation for the reaction of AgNO3(aq) with KBr(aq).
A) Ag+(aq) + NO3-(aq) + K+(aq) + Br-(aq) → Ag+(aq) + Br-(aq) + KNO3(s)
28) ______
B) Ag+(aq) + Br-(aq) → AgBr(s)
C) Ag+(aq) + NO3-(aq) + K+(aq) + Br-(aq) → AgBr(s) + K+(aq) + NO3-(aq)
D) AgNO3(aq) + KBr(aq) → AgBr(aq) + KNO3(s)
29) What is the oxidation number change for the iron atom in the reaction:
A) -6
B) +3
C) -3
29) ______
D) +6
30) How many cations are in 10.0 g of sodium phosphate?
A) 2.96 × 1025 cations
B) 9.87 × 1024 cations
C) 3.67 × 1022 cations
D) 1.10 × 1023 cations
30) ______
31) It takes 11.2 kJ of energy to raise the temperature of 145 g of benzene from 25.0°C to 70.0°C.
What is the specific heat of benzene?
A) 1.10 J/(g ∙ °C)
B) 1.72 J/(g ∙ °C)
C) 5.41 J/(g ∙ °C)
D) 3.48 J/(g ∙ °C)
31) ______
32) The mixing of which pair of reactants will result in a precipitation reaction?
A) NaNO3(aq) + NH4Cl(aq)
B) HCl(aq) + Ca(OH)2(aq)
32) ______
C) K2SO4(aq) + Ba(NO3)2(aq)
D) CsI(aq) + NaOH(aq)
33) Find ΔH° for the reaction C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(l).
33) ______
ΔH° = -2046 kJ for the reaction: C3H8(g) + 5 O2(g) → 3 CO2(g) + 4 H2O(g), and the heat of
vaporization of water is 44.0 kJ/mol. Note that H2O is a liquid in the first reaction and a gas in
the second.
A) -1870 kJ
B) -2090 kJ
C) -2222 kJ
D) -2002 kJ
34) What is the concentration of FeCl3 in a solution prepared by dissolving 10.0 g of FeCl 3 in enough
water to make 275 mL of solution?
A) 4.46 M
B) 0.224 M
C) 4.46 × 103 M
D) 2.24 × 10-4 M
35) If the percent yield for the following reaction is 75.0%, and 45.0 g of NO 2 are consumed in the
reaction, how many grams of nitric acid, HNO3(aq), are produced?
3 NO2(g) + H2O(l) → 2 HNO3(aq) + NO(g)
34) ______
35) ______
A) 69.3 g
B) 41.1 g
C) 54.8 g
D) 30.8 g
36) What is the sum of the coefficients when the following equation is balanced using the lowest,
whole numbered coefficients?
___ PH3(g) + ___ O2(g) → ___ P4O10(s) + ___ H2O(g)
A) 10
B) 19
C) 22
36) ______
D) 12
37) What are the coefficients in front of NO3-(aq) and Zn(s) when the following equation is balanced
37) ______
in a basic solution:
___ NO3-(aq) + ___ Zn(s) → ___ Zn2+(aq) + ___ NO(g)?
A) 3, 4
B) 3, 2
C) 2, 3
D) 2, 5
38) For a particular process that is carried out at constant pressure, q = 125 kJ and w = -15 kJ.
Therefore,
A) ΔE = 125 kJ and ΔH = 110 kJ.
B) ΔE = 140 kJ and ΔH = 125 kJ.
C) ΔE = 125 kJ and ΔH = 140 kJ.
D) ΔE = 110 kJ and ΔH = 125 kJ.
38) ______
39) For a process at constant volume,
A) w = 0 and ΔH = q.
C) w = 0 and ΔE = ΔH.
39) ______
B) w = 0 and ΔE = q.
D) q = 0, w = 0, and ΔE = 0.
40) How many grams of AgNO3 are needed to make 250. mL of a solution that is 0.135 M?
A) 5.73 g
B) 0.174 g
C) 9.17 g
40) ______
D) 0.0917 g
41) Ethyl alcohol is produced by the fermentation of glucose, C 6H12O6.
41) ______
C6H12O6(s) → 2 C2H5OH(l) + 2 CO2(g) ΔH° = - 69.1 kJ
Given that the enthalpy of formation is -277.7 kJ/mol for C2H5OH(l) and -393.5 kJ/mol for
CO2(g), find the enthalpy of formation for C6H12O6.
A) -1411.5 kJ/mol
B) -740.3 kJ/mol
C) -1273.3 kJ/mol
D) -602.1 kJ/mol
42) When 0.455 g of anthracene, C14H10, is combusted in a bomb calorimeter that has a water jacket
42) ______
containing 500. g of water, the temperature of the water increases by 8.63°C. Assuming that the
specific heat of water is 4.18 J/(g ∙ °C), and that the heat absorption by the calorimeter is
negligible, estimate the enthalpy of combustion per mole of anthracene.
A) -7070 kJ/mol
B) +39.7 kJ/mol
C) -8120 kJ/mol
D) -39.7 kJ/mol
43) At constant pressure, the combustion of 5.00 g of C2H6(g) releases 259 kJ of heat. What is ΔH for
43) ______
the reaction given below?
2 C2H6(g) + 7 O2(g) → 4 CO2(g) + 6 H2O(l).
A) -779 kJ
B) -3120 kJ
C) -43.2 kJ
D) -1560 kJ
44) What is the empirical formula for ethyl fluoride if the compound contains 49.97% carbon, 10.51%
hydrogen, and 39.52% fluorine by mass?
A) C2H5F
B) C4H10F4
C) C4H10F2
D) C25F2
44) ______
45) What is the reduction half reaction for the chemical reaction in a basic solution
ClO-(aq) + Cr(OH)4-(aq) → CrO42-(aq) + Cl-(aq)?
45) ______
A) ClO-(aq) + H2O(l) + 2e- → Cl-(aq) + 2 OH-(aq)
B) ClO-(aq) + 2 H+(aq) + 2e- → Cl-(aq) + H2O(l)
C)
Cr(OH)4-(aq) → CrO42-(aq) + 4 H+(aq) + 3eD) Cr(OH)4-(aq) + 4 OH-(aq) → CrO42-(aq) + 4 H2O(l) + 3e46) If 100. mL of 0.100 M Na2SO4 is added to 200. mL of 0.150 M NaCl, what is the concentration of
Na+ ions in the final solution? Assume that the volumes are additive.
A) 0.167 M
B) 0.250 M
C) 0.350 M
47) Which one of the following compounds is insoluble in water?
A) Rb2CO3
B) PbSO4
C) K2SO4
48) In which compound is the oxidation state of hydrogen not +1?
A) Na2HSO4
B) NaH
C) H2O
46) ______
D) 0.133 M
47) ______
D) NaNO3
48) ______
D) H2O2
49) Calculate the work energy, w, gained or lost by the system when a gas expands from 15 L to 35 L
against a constant external pressure of 1.5 atm. [1 L ∙ atm = 101 J]
A) +5.3 kJ
B) -5.3 kJ
C) +3.0 kJ
D) -3.0 kJ
49) ______
50) How many iron(II) ions, Fe2+ are there in 5.00 g of FeSO4?
50) ______
A) 1.98 × 1022 iron (II) ions
C) 5.46 × 10-26 iron (II) ions
B) 1.83 × 1025 iron (II) ions
D) 4.58 × 1026 iron (II) ions
51) The reaction Pb(NO3)2(aq) + K2SO4(aq) → PbSO4(s) + 2 KNO3(aq) is best classified as a(n)
A) acid-base neutralization reaction.
C) precipitation reaction.
51) ______
B) single replacement reaction.
D) oxidation-reduction reaction.
52) When silver nitrate reacts with barium chloride, silver chloride and barium nitrate are formed.
How many grams of silver chloride are formed when 10.0 g of silver nitrate reacts with 15.0 g of
barium chloride?
A) 11.9 g
B) 18.8 g
C) 9.40 g
D) 8.44 g
52) ______
53) What is the molar mass of butane if 5.19 × 1016 molecules of butane weigh 5.00 μg?
A) 431 g/mol
B) 172 g/mol
C) 58.0 g/mol
D) 232 g/mol
53) ______
54) Determine the number of water molecules necessary to balance the reduction half reaction of
54) ______
A) 5
B) 7
that occurs in an acidic solution.
C) 4
55) Which one of the following is an empirical formula?
A) C2F6
B) N2H4
C) H2SO4
D) 2
55) ______
D) P4O10
56) Coal gasification can be represented by the equation:
2 C(s) + 2 H2O(g) → CH4(g) + CO2(g)
ΔH = ?
56) ______
Use the following information to find ΔH for the reaction above.
CO(g) + H2(g) → C(s) + H2O(g)
ΔH = -131 kJ
CO(g) + H2O(g) → CO2(g) + H2(g)
ΔH = -41 kJ
CO(g) + 3 H2(g) → CH4(g) + H2O(g)
ΔH = -206 kJ
A) 15 kJ
B) -372 kJ
C) 116 kJ
D) -116 kJ
57) In the reaction between glucose and oxygen, 10.0 g of glucose reacts and 7.50 L of carbon dioxide
is
formed.
What is 57)
the
percent
yield if
the
density
of CO2 is
___
___
1.26 g/L?
C
6
H
1
2
O
6
(
s
)
+
6
O
2
(
g
)
→
6
C
O
2
(
g
)
+
6
H
2
O
(
l
)
A) 26.1%
B) 43.1%
C) 40.6%
D) 64.5%
58) Which species functions as the reducing agent in the following reduction-oxidation reaction:
2 P(s) + 3 Br2(l) → 2 PBr3(l)?
A) Br2(l)
B) P(s)
C) Br-(aq)
D) P3+(aq)
58) ______
59) Which species functions as the oxidizing agent in the following reduction-oxidation reaction:
59) ______
A) Mn2+(aq)
B) MnO4-(aq)
C) H+(aq)
D) Fe2+(aq)
60) How much heat is absorbed/released when 20.00 g of NH3(g) reacts in the presence of excess
60) ______
O2(g) to produce NO(g) and H2O(l) according to the following chemical equation?
4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(l)
ΔH° = +1168 kJ
A) 1372 kJ of heat are absorbed.
C) 342.9 kJ of heat are absorbed.
B) 1372 kJ of heat are released.
D) 342.9 kJ of heat are released.
61) What is the stoichiometric coefficient for oxygen when the following equation is balanced using
the lowest, whole-number coefficients
________ C3H8O(l) + ________ O2(g) → ________ CO2(g) + ________ H2O(l)
A) 9
B) 5
C) 7
61) ______
D) 3
62) How many milliliters of 0.200 M FeCl3 are needed to react with an excess of Na2S to produce
62) ______
2.75 g of Fe2S3 if the percent yield for the reaction is 65.0%?
3 Na2S(aq) + 2 FeCl3(aq) → Fe2S3(s) + 6 NaCl(aq)
A) 86.0 mL
B) 102 mL
C) 50.9 mL
D) 203 mL
63) What is the concentration of NO3- ions in a solution prepared by dissolving 15.0 g of Ca(NO 3)2
in enough water to produce 300. mL of solution?
A) 0.403 M
B) 0.305 M
C) 0.609 M
D) 0.152 M
64) Find ΔH for BaCO3 (s) → BaO (s)+ CO2 (g)
given
64) ______
2 Ba (s) + O2 (g) → 2 BaO (s)
ΔH = -1107.0 kJ
Ba (s) + CO2 (g) + 1/2 O2 (g) → BaCO3 (g)
ΔH = -822.5 kJ
A) 269.0 kJ
B) -1376.0 kJ
C) -1929.5 kJ
D) -284.5 kJ
65) What is the oxidation number of the sulfur atom in H 2SO4?
A) +6
B) -2
C) +4
65) ______
D) +2
66) What is the mass of 8.50 × 1022 molecules of NH3?
A) 2.40 g
B) 0.417 g
63) ______
66) ______
C) 120 g
D) 0.00830 g
67) What mass of sulfur hexafluoride, SF6, has the same number of fluorine atoms as 25.0 g of
67) ______
oxygen difluoride, OF2?
A) 22.5 g
B) 8.33 g
C) 0.901 g
D) 203 g
68) One method for making ethanol, C2H5OH, involves the gas-phase hydration of ethylene, C2H4:
Estimate ΔH for this reaction from the given average bond dissociation energies, D.
A) -580 kJ
B) 580 kJ
C) +35 kJ
D) -35 kJ
68) ______
69) How many grams of the excess reagent are left over when 6.00 g of CS2 gas react with 10.0 g of
69) ______
Cl2 gas in the following reaction:
CS2(g) + 3 Cl2(g) → CCl4(l) + S2Cl2(l)
A) 2.77 g
B) 3.58 g
C) 2.42 g
D) 4.00 g
70) When 280. mL of 1.50 × 10-4 M hydrochloric acid is added to 125 mL of 1.75 × 10-4 M
Mg(OH)2, the resulting solution will be
A)
B)
C)
D)
70) ______
acidic.
neutral.
basic.
It is impossible to tell from the information given.
71) What are the coefficients in front of NO3-(aq) and Cu(s) when the following redox equation is
71) ______
balanced in an acidic solution:
___ NO3-(aq) + ___ Cu(s) → ___ NO(g) + ___ Cu2+(aq)?
A) 3, 4
B) 2, 3
C) 2, 6
D) 3, 6
72) How many grams of CaCl2 are formed when 35.00 mL of 0.00237 M Ca(OH) 2 reacts with excess
72) ______
Cl2 gas?
2 Ca(OH)2(aq) + 2 Cl2(g) → Ca(OCl)2(aq) + CaCl2(aq) + 2 H2O(l)
A) 0.00921 g
B) 0.0184 g
C) 0.0217 g
D) 0.00460 g
73) Balance the chemical equation given below, and determine the number of moles of iodine that
reacts with 10.0 g of aluminum.
___ Al(s) + ___ I2(s) → ___ Al2I6(s)
A) 1.11 mol
B) 0.556 mol
C) 0.741 mol
D) 0.247 mol
74) What is the oxidation number change for the manganese atom in the following unbalanced
reduction half reaction:
A) +5
B) -7
C) -5
C) C(s)
74) ______
D) +7
75) Which species functions as the reducing agent in the following reduction-oxidation reaction:
ZnO(s) + C(s) → Zn(s) + CO(g)?
A) CO(g)
B) Zn(s)
73) ______
75) ______
D) ZnO(s)
76) What is the reduction half reaction for the chemical reaction in a basic solution
Mn2+(aq) + 2 ClO3-(aq) + OH-(aq) → MnO2(s) + 2 ClO2(aq) + H2O(l)?
76) ______
A) ClO3-(aq) + H2O(l) + e- → ClO2(aq) + 2 OH-(aq)
B) ClO3-(aq) + 2 H+(aq) + e- → ClO2(aq) + H2O(l)
C) Mn2+(aq) + 4 OH-(aq) → MnO2(s) + 2 H2O(l) + 2eD) Mn2+(aq) + 2 H2O(l) → MnO2(s) + 4 H+(aq) + 2e77) The reaction Cu(s) + 2 AgNO3(aq) → Cu(NO3)2(aq) + 2 Ag(s) is best classified as a(n)
A) oxidation-reduction reaction.
C) double replacement reaction.
B) acid-base neutralization reaction.
D) precipitation reaction.
77) ______
78) Determine the number of water molecules necessary to balance the reduction half reaction of
that occurs in a basic solution.
B) 5
C) 4
A) 2
78) ______
D) 3
79) The specific heat of copper is 0.385 J/(g ∙ °C). If 34.2 g of copper, initially at 25°C, absorbs 4.689 kJ,
what will be the final temperature of the copper?
A) 25.4°C
B) 27.8°C
C) 381°C
D) 356°C
79) ______
80) The reaction 2 HNO3(aq) + Ba(OH)2(aq) → Ba(NO3)2(aq) + 2 H2O(l) is best classified as a(n)
80) ______
A) precipitation reaction.
C) acid-base neutralization reaction.
B) oxidation-reduction reaction.
D) single replacement reaction.
81) What is the concentration of HCl in the final solution when 65 mL of a 12 M HCl solution is
diluted with pure water to a total volume of 0.15 L?
A) 5.2 M
B) 28 M
C) 5.2 × 103 M
D) 2.8 × 10-2 M
81) ______
82) Based on the balanced chemical equation shown below, what volume of 0.250 M K 2S2O3(aq) is
82) ______
needed to completely react with 12.44 mL of 0.125 M KI 3(aq)?
2 S2O32-(aq) + I3-(aq) → S4O62-(aq) + 3 I-(aq).
A) 12.4 mL
B) 49.8 mL
C) 6.22 mL
D) 3.11 mL
83) A compound responsible for the odor of garlic has a molecular weight of 146 g/mol. A 0.650 g
sample of the compound contains 0.321 g of carbon, 0.044 g of hydrogen, and 0.285 g of sulfur.
What is the molecular formula of the compound?
A) C3H15S3
B) C3H5S
C) C6H10S2
D) CH5S
83) ______
84) When 5.00 × 1022 molecules of ammonia react with 4.00 × 1022 molecules of oxygen according to
the chemical equation shown below, how many grams of nitrogen gas are produced?
4 NH3(g) + 3 O2(g) → 2 N2(g) + 6 H2O(g)
84) ______
A) 4.65 g
B) 2.79 g
C) 1.16 g
D) 1.24 g
85) How many milliliters of a 9.0 M H2SO4 solution are needed to make 0.25 L of a 3.5 M H2SO4
solution?
A) 0.64 mL
B) 0.097 mL
C) 97 mL
85) ______
D) 640 mL
86) A process is carried out at constant pressure. Given that ΔE is positive and ΔH is negative,
A) the system absorbs heat and expands during the process.
B) the system loses heat and expands during the process.
C) the system loses heat and contracts during the process.
D) the system absorbs heat and contracts during the process.
86) ______
87) What is the identity of substance X if 0.380 mol of X weighs 17.5 g?
A) NO3
B) NO2
C) N2O
87) ______
D) N2O4
88) If the reaction of phosphate ion with water is ignored, what is the total concentration of ions in a
solution prepared by dissolving 3.00 g of K3PO4 in enough water to make 350. mL of solution?
A) 0.0101 M
B) 0.162 M
C) 0.323 M
88) ______
D) 0.0404 M
89) When K2SO4(aq) and Pb(NO3)2(aq) are mixed, a white colored precipitate forms which is
A) PbSO4.
B) K2SO3.
C) KNO3.
D) Pb.
89) ______
90) What is the molarity of a potassium triiodide solution, KI3(aq), if 30.00 mL of the solution is
required to completely react with 25.00 mL of a 0.200 M thiosulfate solution, Na 2S2O3(aq)? The
chemical equation for the reaction is
2 S2O32-(aq) + I3-(aq) → S4O62-(aq) + 3 I-(aq).
A) 0.120 M
B) 0.167 M
C) 0.333 M
D) 0.0833 M
90) ______
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
14)
15)
16)
17)
18)
19)
20)
21)
22)
23)
24)
25)
26)
27)
28)
29)
30)
31)
32)
33)
34)
35)
36)
37)
38)
39)
40)
41)
42)
43)
44)
45)
46)
47)
48)
49)
50)
51)
A
A
A
C
A
D
C
B
B
A
D
B
C
B
C
A
C
C
C
C
B
C
C
A
B
B
A
B
C
D
B
C
C
B
D
B
C
D
B
A
C
A
B
A
A
A
B
B
D
A
C
52)
53)
54)
55)
56)
57)
58)
59)
60)
61)
62)
63)
64)
65)
66)
67)
68)
69)
70)
71)
72)
73)
74)
75)
76)
77)
78)
79)
80)
81)
82)
83)
84)
85)
86)
87)
88)
89)
90)
D
C
C
C
A
D
B
B
C
A
D
C
A
A
A
A
D
C
C
B
D
B
C
C
A
A
A
C
C
A
A
C
C
C
C
B
B
A
D