Exam
Name_____Stoichiomety______
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
1) Calculate the molar mass of Al(C2H3O2)3.
1)
A) 56.00 g/mol
B) 139.99 g/mol
C) 204.13 g/mol
D) 86.03 g/mol
E) 258.09 g/mol
2) How many N2O4 molecules are contained in 76.3 g N2O4? The molar mass of N2O4 is 92.02
2)
g/mol.
A) 5.54 × 10 25 N2O4 molecules
B) 7.26 × 10 23 N2O4 molecules
C) 4.59 × 10 25 N2O4 molecules
D) 4.99 × 10 23 N2O4 molecules
E) 1.38 × 10 24 N2O4 molecules
3) What is the mass (in kg) of 6.89 × 10 25 molecules of CO2? The molar mass of CO 2 is 44.01
g/mol.
A) 2.60 kg
B) 6.39 kg
C) 5.04 kg
D) 3.03 kg
3)
E) 3.85 kg
4) Write a balanced equation to show the reaction of aqueous aluminum acetate with aqueous
ammonium phosphate to form solid aluminum phosphate and aqueous ammonium acetate.
A) Al(C2H3O2)2 (aq) + (NH3)2PO4 (aq) → AlPO4 (s) + 2 NH3C2H3O3 (aq)
4)
B) Al(C2H3O2)3 (aq) + (NH4)3PO4 (aq) → AlPO4 (s) + 3 NH4C2H3O3 (aq)
C) Al(CO2)3 (aq) + (NH4)3PO3 (aq) → AlPO3 (s) + 3 NH4CO2 (aq)
D) Al(C2H3O2)2 (aq) + (NH4)2PO4 (aq) → AlPO4 (s) + 2 NH4C2H3O3 (aq)
E) Al(CO3)2 (aq) + (NH3)2PO4 (aq) → AlPO4 (s) + 2 NH3CO3 (aq)
5) According to the following balanced reaction, how many moles of NO are formed from 8.44
moles of NO2 if there is plenty of water present?
3 NO 2(g) + H2O(l) → 2 HNO 3(aq) + NO(g)
A) 2.81 moles NO
B) 1.83 moles NO
C) 8.44 moles NO
D) 25.3 moles NO
E) 5.50 moles NO
1
5)
6) Consider the following reaction. How many moles of oxygen are required to produce 2.33 moles
of water? Assume that there is excess C3H7SH present.
6)
C3H7SH(l) + 6 O 2(g) → 3 CO2(g) + SO 2(g) + 4 H2O (g)
A) 2.33 moles O 2
B) 6.21 moles O 2
C) 3.50 moles O 2
D) 4.14 moles O 2
E) 1.55 moles O 2
7) Consider the following balanced reaction. How many grams of water are required to form 75.9
g of HNO3? Assume that there is excess NO2 present. The molar masses are as follows: H2O =
7)
18.02 g/mol, HNO3 = 63.02 g/mol.
3 NO 2(g) + H2O(l) → 2 HNO 3(aq) + NO(g)
A) 38.0 g H2O
B) 26.5 g H2O
C) 10.9 g H2O
D) 21.7 g H2O
E) 43.4 g H2O
8) According to the following reaction, how many grams of sulfur are formed when 37.4 g of water
are formed?
2 H2S(g) + SO2(g) → 3 S(s) + 2H2O(l)
A) 66.6 g S
B) 56.1 g S
C) 44.4 g S
D) 14.0 g S
E) 99.8 g S
9) Consider the following balanced reaction. What mass (in g) of CO2 can be formed from 288 mg
of O2? Assume that there is excess C 3H7SH present.
C3H7SH(l) + 6 O2(g) → 3 CO2(g) + SO 2(g) + 4 H2O (g)
A) 0.396 g CO2
B) 0.209 g CO2
C) 0.126 g CO2
D) 0.198 g CO2
E) 0.792 g CO2
2
8)
9)
10) Calculate the molar mass of Ca3(PO4)2.
10)
A) 279.21 g/mol
B) 215.21 g/mol
C) 246.18 g/mol
D) 87.05 g/mol
E) 310.18 g/mol
11) Write a balanced equation to show the reaction of sulfurous acid with lithium hydroxide to form
water and lithium sulfite.
A) HSO 4 (aq) + LiOH (aq) → H2O (l) + LiSO 4 (aq)
11)
B) H2SO4 (aq) + LiOH (aq) → H2O (l) + Li 2SO4 (aq)
C) H2S (aq) + 2 LiOH (aq) → 2 H2O (l) + Li 2S (aq)
D) H2SO3 (aq) + 2 LiOH (aq) → 2 H2O (l) + Li2SO3 (aq)
E) HSO 3 (aq) + LiOH (aq) → H2O (l) + LiSO 3 (aq)
0.621 moles KOH
12) How many grams of oxygen are formed when xxx
6.21 moles of KOH are formed?
12)
4 KO(s) + 2 H2O(l) → 4 KOH(s) + O 2(g)
A) 11.7 g O 2
B) 27.9 g O2
C) 3.59 g O2
D) 19.9 g O2
E) 4.97 g O2
13) How many molecules of HCl are formed when 50.0 g of water reacts according to the following
balanced reaction? Assume excess ICl3.
13)
2 ICl3 + 3 H2O → ICl + HIO 3 + 5 HCl
A) 6.09 × 10 25 molecules HCl
B) 2.78 × 10 24 molecules HCl
C) 3.65 × 10 24 molecules HCl
D) 1.67 × 10 24 molecules HCl
E) 5.02 × 10 25 molecules HCl
14) Determine the percent yield of a reaction that produces 28.65 g of Fe when 50.00 g of Fe 2O3 react
with excess Al according to the following reaction.
Fe 2O3(s) + 2 Al(s) → Al2O3(s) + 2 Fe(s)
A) 57.30 %
B) 61.03 %
C) 81.93 %
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D) 28.65 %
E) 20.02 %
14)
Answer Key
Testname: UNTITLED1
1) C
2) D
3) C
4) B
5) A
6) C
7) C
8) E
9) D
10) E
11) D
12) E
13) B
14) C
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