Question 1

You have 10.00 L of a 0.350 M KCl solution, but you need a solution that is 0.450 M. What volume of water, in L, would you evaporate from the solution?

Accepted Answer

A)  4.38 L 
B)  3.50 L 
C)  2.85 L 
D)  7.77 L 
E)  2.22 L 
A)  4.38 L 
B)  3.50 L 
C)  2.85 L 
D)  7.77 L 
E)  2.22 L

Question 2

What mass of trisodium phosphate is required to prepare 250.0 mL of a solution that is 0.30 M in sodium ion?

Accepted Answer

A)  37 g 
B)  12 g 
C)  7.7 g 
D)  4.1 g 
E)  3.0 g 
A)  37 g 
B)  12 g 
C)  7.7 g 
D)  4.1 g 
E)  3.0 g

Question 3

What is the molarity of 10.9 g KCl dissolved in 150.0 mL of water?

Accepted Answer

A)  0.0727 M 
B)  0.146 M 
C)  0.975 M 
D)  0.0219 M 
E)  0.667 M 
A)  0.0727 M 
B)  0.146 M 
C)  0.975 M 
D)  0.0219 M 
E)  0.667 M

Question 4

Cryolite is a compound needed for the Hall-Heroult process for producing aluminum. Cryolite is produced by the following reaction: 6 HF + Al(OH)3 + 3 NaOH → Na3AlF6 + 6 H2O
How many grams of cryolite are produced if the reaction has a 67.3% yield and a limiting reagent of 35.4 grams of NaOH?

Accepted Answer

A)  61.9 g 
B)  41.7 g 
C)  125 g 
D)  186 g 
E)  20.2 g 
A)  61.9 g 
B)  41.7 g 
C)  125 g 
D)  186 g 
E)  20.2 g

Question 5

What mass of oxygen gas would be consumed by the complete combustion of 7.5 g of a mixture of propane (C3H8) and butane (C4H10) in the mole ratio of C3H8/C4H10 = 1.33?

Accepted Answer

A)  3.9 g 
B)  11 g 
C)  14 g 
D)  21 g 
E)  27 g 
A)  3.9 g 
B)  11 g 
C)  14 g 
D)  21 g 
E)  27 g

Question 6

42.6 g Cu are combined with 84.0 g of HNO3 according to the reaction: 3 Cu + 8 HNO3 → 3 Cu(NO3)2 + 2 NO + 4 H2O.
Which reagent is limiting and how many grams of Cu(NO3)2 are produced?

Accepted Answer

A)  Cu, 93.8 g 
B)  HNO3, 93.8 g 
C)  Cu, 125.6 g 
D)  HNO3, 125.6 g 
E)  Cu(NO3)2, 125.6 g 
A)  Cu, 93.8 g 
B)  HNO3, 93.8 g 
C)  Cu, 125.6 g 
D)  HNO3, 125.6 g 
E)  Cu(NO3)2, 125.6 g

Question 7

What is the sum of the coefficients when the following is balanced with the smallest integer coefficients? Al(s) + HCl(aq) → AlCl3(aq) + H2(g)

Accepted Answer

A)  13 
B)  11 
C)  18 
D)  19 
E)  21 
A)  13 
B)  11 
C)  18 
D)  19 
E)  21

Question 8

What is the sum of the coefficients when the following is balanced with the smallest integer coefficients? C2H6 + O2 → CO2 + H2O

Accepted Answer

A)  5 
B)  10 
C)  19 
D)  21 
E)  25 
A)  5 
B)  10 
C)  19 
D)  21 
E)  25

Question 9

One source of iodine is sodium iodate. Iodine is produced by a series of reactions. The first reaction is a reduction reaction with sodium hydrogen sulfite. IO3-( aq) + 3 HSO3- (aq) → I- (aq) + 3 SO42- (aq) + 3 H+(aq)
5 I- (aq) + IO3- (aq) + 6 H+ (aq) → 3 I2(s) + 3 H2O
How many grams of iodine are produced from 1.00 × 102 grams of NaHSO3 if each reaction has a 95.0% yield?

Accepted Answer

A)  48.8 g 
B)  51.4 g 
C)  185 g 
D)  46.3 g 
E)  44.0 g 
A)  48.8 g 
B)  51.4 g 
C)  185 g 
D)  46.3 g 
E)  44.0 g

Question 10

"Washing soda" (sodium carbonate) may be used to "soften" water by the removal of certain ions that would otherwise react with common soaps. When the "hardness" is due to calcium ion, the "softening" process may be represented as: Ca2+(aq) + CO32-(aq) → CaCO3(s)
What mass of sodium carbonate would be required to remove essentially all of the calcium ion from 750 L of solution containing 43 mg Ca2+ per liter?

Accepted Answer

A)  85 g 
B)  67 g 
C)  12 g 
D)  48 g 
E)  22 g 
A)  85 g 
B)  67 g 
C)  12 g 
D)  48 g 
E)  22 g

Question 11

24.0 g of ethane (C2H6) are burned to form CO2 and H2O. How many grams of CO2 are produced?

Accepted Answer

A)  32.8 g 
B)  14.4 g 
C)  43.2 g 
D)  35.1 g 
E)  70.3 g 
A)  32.8 g 
B)  14.4 g 
C)  43.2 g 
D)  35.1 g 
E)  70.3 g

Question 12

Given the following reactions: Fe + Br2 → FeBr2
3 FeBr2 + Br2 → Fe3Br8
If each reaction is 82.0% efficient, what mass of iron is necessary to make 8.45 g of Fe3Br8?

Accepted Answer

A)  0.870 g 
B)  3.73 g 
C)  2.14 g 
D)  1.75 g 
E)  2.61 g 
A)  0.870 g 
B)  3.73 g 
C)  2.14 g 
D)  1.75 g 
E)  2.61 g

Question 13

What is the percent yield if 185 grams of SiO2 are made from 328 g of Cr2O3 by the following equation? 3 Si(s) + 2 Cr2O3(s) → 3 SiO2(s) + 4 Cr(l)

Accepted Answer

A)  142% 
B)  70% 
C)  56% 
D)  105% 
E)  95% 
A)  142% 
B)  70% 
C)  56% 
D)  105% 
E)  95%

Question 14

How many grams of sulfuric acid, H2SO4, can be obtained from 578 grams of iron ore if the ore is 76.0% by mass FeS? The reactions involved are given below. Each reaction is 92.0% efficient. 4 FeS + 7O2 → 2 Fe2O3 + 4 SO2
2 SO2 + O2 → 2 SO3
SO3 + H2O → H2SO4

Accepted Answer

A)  502 g 
B)  307 g 
C)  382 g 
D)  95.5 g 
E)  629 g 
A)  502 g 
B)  307 g 
C)  382 g 
D)  95.5 g 
E)  629 g

Question 15

If the percent yield is 82.0%, how many grams of silicon is needed to make 105 g of chromium by the reaction: 3 Si (s) + 2 Cr203 (s) → 3 SiO2 (s) + 4 Cr (l)?

Accepted Answer

A)  51.9 g 
B)  92.2 g 
C)  42.5 g 
D)  34.9 g 
E)  13.0 g 
A)  51.9 g 
B)  92.2 g 
C)  42.5 g 
D)  34.9 g 
E)  13.0 g

Question 16

Acetylene gas may be produced by carefully adding water to calcium carbide, according to the equation: CaC2(s) + 2 H2O(l) → Ca(OH)2(s) + C2H2(g)
When a 37 g sample of an impure calcium carbide was treated with excess water, 13 g of acetylene gas was produced. If the reaction is essentially 100% efficient, what was the percentage of nonreacting impurity in the carbide sample?

Accepted Answer

A)  86% 
B)  58% 
C)  42% 
D)  35% 
E)  13.5% 
A)  86% 
B)  58% 
C)  42% 
D)  35% 
E)  13.5%

Question 17

What is the sum of the coefficients in the balanced equation that represents the complete combustion of the relatively new gasoline additive "MTBE," for which the molecular formula is C5H12O?

Accepted Answer

A)  39 
B)  37 
C)  29 
D)  24 
E)  20 
A)  39 
B)  37 
C)  29 
D)  24 
E)  20

Question 18

What is the percent yield if 122 grams of SiO2 are made from 246 g of Cr2O3 by the following equation? 3 Si(s) + 2 Cr2O3(s) → 3 SiO2(s) + 4 Cr(l)

Accepted Answer

A)  83.6% 
B)  49.6% 
C)  125% 
D)  33.1% 
E)  59.3% 
A)  83.6% 
B)  49.6% 
C)  125% 
D)  33.1% 
E)  59.3%

Question 19

What is the molarity of formaldehyde in a solution containing 0.25 g of formaldehyde (CH2O) per mL?

Accepted Answer

A)  2.5 M 
B)  25 M 
C)  8.3 M 
D)  83 M 
E)  4.0 M 
A)  2.5 M 
B)  25 M 
C)  8.3 M 
D)  83 M 
E)  4.0 M

Question 20

Nitroglycerin, used both in medicine and as an explosive, can be prepared by the carefully controlled reaction of glycerol (C3H8O3) with nitric acid, as symbolized by: C3H8O3 + 3 HNO3 → C3H5N3O9 + 3 H2O
What mass of nitric acid is required for the production of 2.8 g of nitroglycerin by a process having a 67% yield?

Accepted Answer

A)  2.3 g 
B)  0.39 g 
C)  1.6 g 
D)  3.5 g 
E)  1.2 g 
A)  2.3 g 
B)  0.39 g 
C)  1.6 g 
D)  3.5 g 
E)  1.2 g

Exam 4: Chemical Reactions

You have 10.00 L of a 0.350 M KCl solution, but you need a solution that is 0.450 M. What volume of water, in L, would you evaporate from the solution?

What mass of trisodium phosphate is required to prepare 250.0 mL of a solution that is 0.30 M in sodium ion?

What is the molarity of 10.9 g KCl dissolved in 150.0 mL of water?

Cryolite is a compound needed for the Hall-Heroult process for producing aluminum. Cryolite is produced by the following reaction: 6 HF + Al(OH)3 + 3 NaOH → Na3AlF6 + 6 H2O How many grams of cryolite are produced if the reaction has a 67.3% yield and a limiting reagent of 35.4 grams of NaOH?

What mass of oxygen gas would be consumed by the complete combustion of 7.5 g of a mixture of propane (C3H8) and butane (C4H10) in the mole ratio of C3H8/C4H10 = 1.33?

42.6 g Cu are combined with 84.0 g of HNO3 according to the reaction: 3 Cu + 8 HNO3 → 3 Cu(NO3)2 + 2 NO + 4 H2O. Which reagent is limiting and how many grams of Cu(NO3)2 are produced?

What is the sum of the coefficients when the following is balanced with the smallest integer coefficients? Al(s) + HCl(aq) → AlCl3(aq) + H2(g)

What is the sum of the coefficients when the following is balanced with the smallest integer coefficients? C2H6 + O2 → CO2 + H2O

24.0 g of ethane (C2H6) are burned to form CO2 and H2O. How many grams of CO2 are produced?

Given the following reactions: Fe + Br2 → FeBr2 3 FeBr2 + Br2 → Fe3Br8 If each reaction is 82.0% efficient, what mass of iron is necessary to make 8.45 g of Fe3Br8?

What is the percent yield if 185 grams of SiO2 are made from 328 g of Cr2O3 by the following equation? 3 Si(s) + 2 Cr2O3(s) → 3 SiO2(s) + 4 Cr(l)

How many grams of sulfuric acid, H2SO4, can be obtained from 578 grams of iron ore if the ore is 76.0% by mass FeS? The reactions involved are given below. Each reaction is 92.0% efficient. 4 FeS + 7O2 → 2 Fe2O3 + 4 SO2 2 SO2 + O2 → 2 SO3 SO3 + H2O → H2SO4

If the percent yield is 82.0%, how many grams of silicon is needed to make 105 g of chromium by the reaction: 3 Si (s) + 2 Cr203 (s) → 3 SiO2 (s) + 4 Cr (l)?

What is the sum of the coefficients in the balanced equation that represents the complete combustion of the relatively new gasoline additive "MTBE," for which the molecular formula is C5H12O?

What is the percent yield if 122 grams of SiO2 are made from 246 g of Cr2O3 by the following equation? 3 Si(s) + 2 Cr2O3(s) → 3 SiO2(s) + 4 Cr(l)

What is the molarity of formaldehyde in a solution containing 0.25 g of formaldehyde (CH2O) per mL?

Matter - Its Properties and Measurement

Atoms and the Atomic Theory

Chemical Compounds

Introduction to Reactions in Aqueous Solutions

Gases

Thermochemistry

Electrons in Atoms

The Periodic Table and Some Atomic Properties

Chemical Bonding I: Basic Concepts

Chemical Bonding II: Additional Aspects

Intermolecular Forces: Liquids and Solids

Solutions and Their Physical Properties

Chemical Kinetics

Principles of Chemical Equilibrium

Acids and Bases

Additional Aspects of Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Spontaneous Change: Entropy and Free Energy

Electrochemistry

Main Group Elements I: Groups 1, 2, 13, and 14

Main Group Elements II: Groups 18, 17, 16, 15, and Hydrogen

The Transition Elements

Complex Ions and Coordination Compounds

Nuclear Chemistry 1-41

Structures of Organic Compounds

Reactions of Organic Compounds

Chemistry of the Living State

Filters

What mass of oxygen gas would be consumed by the complete combustion of 7.5 g of a mixture of propane (C₃H₈) and butane (C₄H₁₀) in the mole ratio of C₃H₈/C₄H₁₀ = 1.33?

42.6 g Cu are combined with 84.0 g of HNO₃ according to the reaction: 3 Cu + 8 HNO₃ → 3 Cu(NO₃)₂ + 2 NO + 4 H₂O. Which reagent is limiting and how many grams of Cu(NO₃)₂ are produced?

What is the sum of the coefficients when the following is balanced with the smallest integer coefficients? Al(s) + HCl(aq) → AlCl₃(aq) + H₂(g)

What is the sum of the coefficients when the following is balanced with the smallest integer coefficients? C₂H₆+ O₂ → CO₂+ H₂O

24.0 g of ethane (C₂H₆) are burned to form CO₂ and H₂O. How many grams of CO₂ are produced?

Given the following reactions: Fe + Br₂ → FeBr₂ 3 FeBr₂ + Br₂ → Fe₃Br₈ If each reaction is 82.0% efficient, what mass of iron is necessary to make 8.45 g of Fe₃Br₈?

What is the percent yield if 185 grams of SiO₂ are made from 328 g of Cr₂O₃ by the following equation? 3 Si(s) + 2 Cr₂O₃(s) → 3 SiO₂(s) + 4 Cr(l)

How many grams of sulfuric acid, H₂SO₄, can be obtained from 578 grams of iron ore if the ore is 76.0% by mass FeS? The reactions involved are given below. Each reaction is 92.0% efficient. 4 FeS + 7O₂ → 2 Fe₂O₃ + 4 SO₂ 2 SO₂ + O₂ → 2 SO₃ SO₃ + H₂O → H₂SO₄

If the percent yield is 82.0%, how many grams of silicon is needed to make 105 g of chromium by the reaction: 3 Si (s) + 2 Cr₂0₃ (s) → 3 SiO₂ (s) + 4 Cr (l)?

What is the percent yield if 122 grams of SiO₂ are made from 246 g of Cr₂O₃ by the following equation? 3 Si(s) + 2 Cr₂O₃(s) → 3 SiO₂(s) + 4 Cr(l)

What is the molarity of formaldehyde in a solution containing 0.25 g of formaldehyde (CH₂O) per mL?