Question 1

Caffeine has the molecular formula, C₈H₁₀ N₄ O₂. If it is burned in excess oxygen it will form carbon dioxide, water vapor, and nitrogen gas. Which gas will be most abundant by mass?

Accepted Answer

A)   CO₂
B)   H₂O
C)   N₂
D)   they will all the be the same
E)   it depends on the mass of caffeineF) C) and D)
G) All of the above

Question 2

Triphenylene is an organic compound containing only carbon and hydrogen with 3 carbon atoms for every two hydrogen atoms.  Which of the following is a possible molecular mass for triphenylene?

Accepted Answer

A)   34.0 g/mol
B)   228.29 g/mol
C)   366.8 g/mol
D)   400.0 g/mol
E)   b or c could be correctF) D) and E)
G) A) and E)

Question 3

A vanadium oxide contains 56.02% vanadium by mass. What is its empirical formula?

Accepted Answer

A)   V₂O
B)   VO
C)   V₂O₃
D)   VO₂
E)   V₂O₅F) D) and E)
G) C) and E)

Question 4

You have a compound that contains only carbon and hydrogen. If you burn the compound at high temperature in the presence of oxygen it is completely converted to CO2 and H2O. When you react 20.0 g of your sample you generate 62.7 g of CO2 and 25.7 g of H2O. Which of the following is a possible formula for your compound?

Accepted Answer

A)   C2H2
B)   C2H4
C)   C2H6
D)   C3H5
E)   C3H7F) All of the above
G) A) and B)

Question 5

Nitrogen gas reacts with hydrogen gas to produce ammonia.
3 H2(g)  + N2(g)  → 2 NH3(g) 
How many grams of nitrogen are required to produce 1.000 g of ammonia?

Accepted Answer

A)   0.8224
B)   1.644
C)   0.5000
D)   0.6667
E)   0.4112F) None of the above
G) B) and D)

Question 6

Sodium perbromate can be synthesized via the following reaction that gives off Xenon gas.  NaBrO3+XeF2+H2O→NaBrO4+2HF+Xe\mathrm{NaBrO}_{3}+\mathrm{XeF}_{2}+\mathrm{H}_{2} \mathrm{O} \rightarrow \mathrm{NaBrO}_{4}+2 \mathrm{HF}+\mathrm{Xe}NaBrO3​+XeF2​+H2​O→NaBrO4​+2HF+Xe  A reaction is started with 200.0g of NaBrO₃, 250.0g of XeF₂ and 100.0g of water.  Assuming that the reaction goes to completion, and that all of the formed xenon gas is allowed to escape into the atmosphere, what will be the minimum mass of products and reactants remaining in the reaction vessel?

Accepted Answer

A)   173.4 g
B)   193.9 g
C)   376.0 g
D)   356.1 g
E)   None of the above F) A) and D)
G) A) and C) C

Question 7

Calcium carbide, CaC₂, reacts with water to produce calcium hydroxide and acetylene gas, C₂H₂.  CaC2(s) +2H2O(l) →Ca(OH) 2(aq) +C2H2(g) \mathrm{CaC}_{2}(s) +2 \mathrm{H}_{2} \mathrm{O}(l)  \rightarrow \mathrm{Ca}(\mathrm{OH}) _{2}(a q) +\mathrm{C}_{2} \mathrm{H}_{2}(g) CaC2​(s) +2H2​O(l) →Ca(OH) 2​(aq) +C2​H2​(g)   How many grams of acetylene can be produced from 30.0 g of calcium carbide?

Accepted Answer

A)   1.42 g
B)   12.2 g
C)   28.0 g
D)   30.0 g
E)   64.1 g F) C) and D)
G) B) and D) B

Question 8

Barium hydroxide reacts with hydrochloric acid to produce barium chloride and water. A balanced chemical equation for this reaction is?

Accepted Answer

A)   Ba(OH) 2 + HCL → BACL2 + H2O
B)   Ba(OH)  + HCL → BACL + H2O
C)   Ba(OH) 2 + 2HCL → BACL2 + 2H2O
D)   Ba(OH) 2 + 2HCL → BACL2 + H2O
E)   Ba(OH)  + 2HCL → BACL + H2OF) A) and B)
G) A) and C)

Question 9

Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide by the following reaction  Al2 S3+6H2O→2Al(OH) 3+3H2 S\mathrm{Al}_{2} \mathrm{~S}_{3}+6 \mathrm{H}_{2} \mathrm{O} \rightarrow 2 \mathrm{Al}(\mathrm{OH}) _{3}+3 \mathrm{H}_{2} \mathrm{~S}Al2​ S3​+6H2​O→2Al(OH) 3​+3H2​ S  If 25 g of aluminum sulfide is reacted with 25 g of water how many moles of hydrogen sulfide will be formed?

Accepted Answer

A)   0.12 moles
B)   0.50 moles
C)   0.78 moles
D)   2.0 moles
E)   3.0 moles F) A) and D)
G) C) and D)

Question 10

Vitamin B12, cyanocobalamin, has the molecular formula, C68H88CoN14O14P. What is the percent mass of cobalt in this compound?

Accepted Answer

A)   1.02%
B)   4.35%
C)   10.3%
D)   22.3%
E)   23.2%F) A) and C)
G) A) and D)

Question 11

For the given unbalanced reaction
X CaO(s)  + y H2O(l)  → z Ca(OH) 2
The correct stiochiometric coefficients x, y, & z are

Accepted Answer

A)   1,1,1
B)   1,2,1
C)   2,1,2
D)   2,1,1
E)   1,1,2F) B) and E)
G) A) and D)

Question 12

Tetrasilane (Si4H10)  is a liquid with can react with oxygen to form SiO2 and water. How many moles of water are produced from each mole of tetrasilane that reacts?

Accepted Answer

A)   0.1
B)   2.5
C)   4
D)   5
E)   10F) C) and D)
G) A) and D)

Question 13

Iron oxide can be reduced to iron by a reaction with carbon to form carbon monoxide  Fe2O3(s) +3C(s) →2Fe(s) +3CO(g) \mathrm{Fe}_{2} \mathrm{O}_{3}(s) +3 \mathrm{C}(s)  \rightarrow 2 \mathrm{Fe}(s) +3 \mathrm{CO}(g) Fe2​O3​(s) +3C(s) →2Fe(s) +3CO(g)   If 95.0 grams of iron oxide is reacted with excess carbon yields 63 g of iron, what is the percent yield of this reaction?

Accepted Answer

A)   12%
B)   59%
C)   66%
D)   95%
E)   100% F) B) and D)
G) C) and D)

Question 14

Magnetite is a mineral compound that is 72.36% iron and 27.64% oxygen by mass. What is the empirical formula for the compound that makes up magnetite?

Accepted Answer

A)   FeO
B)   Fe2O
C)   Fe2O3
D)   Fe3O2
E)   Fe3O4F) A) and C)
G) D) and E)

Question 15

Assume a kernel of wheat has a volume of 8 mm3. How many moles of wheat kernels can fit in the world's largest grain elevator with a capacity of 20 million bushels (1 bushel = 35.24 L) ?

Accepted Answer

A)   1.17×10-12
B)   1.42×10-12
C)   1.46×10-10
D)   1.46×10-7
E)   1.42×10-6F) All of the above
G) A) and C)

Question 16

Which of the following is not correctly balanced?

Accepted Answer

A)   2 Al + 6 HCl → 2 AlCl3 + 3 H2
B)   2 C6H6 + 15 O2 → 12 CO2 + 6 H2O
C)   16 Cr + 3 S8 → 8 Cr2S3
D)   2 NaHCO3 → Na2CO3 + 2 CO2 + H2O
E)   Fe2O3 + 2 Al → 2 Fe + Al2O3F) B) and E)
G) A) and B)

Question 17

Magnesium will react with carbon dioxide to form magnesium oxide and carbon.
2 Mg(s)  + CO2(g)  → 2MgO(s)  + C(s) 
20) 0 grams of magnesium react completely with excess carbon dioxide. How many grams of solid product should be formed?

Accepted Answer

A)   20.0 grams
B)   27.5 grams
C)   30.0 grams
D)   38.1 grams
E)   40.0 gramsF) A) and B)
G) A) and C)

Question 18

Which of the following carbohydrates has the largest percent mass of carbon?

Accepted Answer

A)   threose (C4H8O4) 
B)   ribose (C5H10O5) 
C)   glucose (C6H12O6) 
D)   sucrose (C12H22O11) 
E)   raffinose (C18H32O16) F) A) and C)
G) B) and D)

Question 19

In fermentation, sucrose, C12H22O11, reacts with water to form ethanol, C2H5OH, and carbon dioxide. A balanced chemical equation for this reaction is?

Accepted Answer

A)   C12H22O11(aq)  + 3 H2O(l)  → 5 C2H5OH(aq)  + 2 Co2(g) 
B)   C12H22O11(aq)  + 7 H2O(l)  → 2 C2H5OH(aq)  + 8 Co2(g) 
C)   C12H22O11(aq)  + 2 H2O(l)  → 6 C2H5OH(aq)  + Co2(g) 
D)   C12H22O11(aq)  + 2 H2O(l)  → 4 C2H5OH(aq)  + 4 Co2(g) 
E)   C12H22O11(aq)  + H2O(l)  → 4 C2H5OH(aq)  + 4 Co2(g) F) B) and C)
G) A) and B)

Question 20

Which has a larger molar volume (the volume occupied by one mole) : gold (density = 19.3 g cm⁻³)  or tin (density = 7.31 g cm⁻³) ?

Accepted Answer

A)   gold
B)   tin
C)   they are exactly the same
D)   there is no way to know without other informationE) B) and C)
F) None of the above B

Exam 2: Chemical Formulas, Equations, and Reaction Yields

Caffeine has the molecular formula, C₈H₁₀ N₄ O₂. If it is burned in excess oxygen it will form carbon dioxide, water vapor, and nitrogen gas. Which gas will be most abundant by mass?

Correct Answer
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Triphenylene is an organic compound containing only carbon and hydrogen with 3 carbon atoms for every two hydrogen atoms. Which of the following is a possible molecular mass for triphenylene?

Correct Answer
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A vanadium oxide contains 56.02% vanadium by mass. What is its empirical formula?

Correct Answer
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Correct Answer
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Nitrogen gas reacts with hydrogen gas to produce ammonia. 3 H₂(g) + N₂(g) → 2 NH₃(g) How many grams of nitrogen are required to produce 1.000 g of ammonia?

Correct Answer
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Correct Answer
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C

Correct Answer
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B

Barium hydroxide reacts with hydrochloric acid to produce barium chloride and water. A balanced chemical equation for this reaction is?

Correct Answer
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Correct Answer
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Vitamin B₁₂, cyanocobalamin, has the molecular formula, C₆₈H₈₈CoN₁₄O₁₄P. What is the percent mass of cobalt in this compound?

Correct Answer
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For the given unbalanced reaction X CaO(s) + y H₂O(l) → z Ca(OH) ₂ The correct stiochiometric coefficients x, y, & z are

Correct Answer
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Tetrasilane (Si₄H₁₀) is a liquid with can react with oxygen to form SiO₂ and water. How many moles of water are produced from each mole of tetrasilane that reacts?

Correct Answer
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Correct Answer
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Magnetite is a mineral compound that is 72.36% iron and 27.64% oxygen by mass. What is the empirical formula for the compound that makes up magnetite?

Correct Answer
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Assume a kernel of wheat has a volume of 8 mm³. How many moles of wheat kernels can fit in the world's largest grain elevator with a capacity of 20 million bushels (1 bushel = 35.24 L) ?

Correct Answer
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Which of the following is not correctly balanced?

Correct Answer
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Magnesium will react with carbon dioxide to form magnesium oxide and carbon. 2 Mg(s) + CO₂(g) → 2MgO(s) + C(s) 20) 0 grams of magnesium react completely with excess carbon dioxide. How many grams of solid product should be formed?

Correct Answer
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Which of the following carbohydrates has the largest percent mass of carbon?

Correct Answer
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In fermentation, sucrose, C₁₂H₂₂O₁₁, reacts with water to form ethanol, C₂H₅OH, and carbon dioxide. A balanced chemical equation for this reaction is?

Correct Answer
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Which has a larger molar volume (the volume occupied by one mole) : gold (density = 19.3 g cm⁻³) or tin (density = 7.31 g cm⁻³) ?

Correct Answer
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B

Exam 2: Chemical Formulas, Equations, and Reaction Yields

Caffeine has the molecular formula, C₈H₁₀ N₄ O₂. If it is burned in excess oxygen it will form carbon dioxide, water vapor, and nitrogen gas. Which gas will be most abundant by mass?

Correct AnswerverifiedShow Answer

Triphenylene is an organic compound containing only carbon and hydrogen with 3 carbon atoms for every two hydrogen atoms. Which of the following is a possible molecular mass for triphenylene?

Correct AnswerverifiedShow Answer

A vanadium oxide contains 56.02% vanadium by mass. What is its empirical formula?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Nitrogen gas reacts with hydrogen gas to produce ammonia. 3 H2(g) + N2(g) → 2 NH3(g) How many grams of nitrogen are required to produce 1.000 g of ammonia?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedC

Correct AnswerverifiedB

Barium hydroxide reacts with hydrochloric acid to produce barium chloride and water. A balanced chemical equation for this reaction is?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Vitamin B12, cyanocobalamin, has the molecular formula, C68H88CoN14O14P. What is the percent mass of cobalt in this compound?

Correct AnswerverifiedShow Answer

For the given unbalanced reaction X CaO(s) + y H2O(l) → z Ca(OH) 2 The correct stiochiometric coefficients x, y, & z are

Correct AnswerverifiedShow Answer

Tetrasilane (Si4H10) is a liquid with can react with oxygen to form SiO2 and water. How many moles of water are produced from each mole of tetrasilane that reacts?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Magnetite is a mineral compound that is 72.36% iron and 27.64% oxygen by mass. What is the empirical formula for the compound that makes up magnetite?

Correct AnswerverifiedShow Answer

Assume a kernel of wheat has a volume of 8 mm3. How many moles of wheat kernels can fit in the world's largest grain elevator with a capacity of 20 million bushels (1 bushel = 35.24 L) ?

Correct AnswerverifiedShow Answer

Which of the following is not correctly balanced?

Correct AnswerverifiedShow Answer

Magnesium will react with carbon dioxide to form magnesium oxide and carbon. 2 Mg(s) + CO2(g) → 2MgO(s) + C(s) 20) 0 grams of magnesium react completely with excess carbon dioxide. How many grams of solid product should be formed?

Correct AnswerverifiedShow Answer

Which of the following carbohydrates has the largest percent mass of carbon?

Correct AnswerverifiedShow Answer

In fermentation, sucrose, C12H22O11, reacts with water to form ethanol, C2H5OH, and carbon dioxide. A balanced chemical equation for this reaction is?

Correct AnswerverifiedShow Answer

Which has a larger molar volume (the volume occupied by one mole) : gold (density = 19.3 g cm⁻³) or tin (density = 7.31 g cm⁻³) ?

Correct AnswerverifiedB

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Nitrogen gas reacts with hydrogen gas to produce ammonia. 3 H₂(g) + N₂(g) → 2 NH₃(g) How many grams of nitrogen are required to produce 1.000 g of ammonia?

Correct Answer
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Correct Answer
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C

Correct Answer
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B

Correct Answer
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Correct Answer
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Vitamin B₁₂, cyanocobalamin, has the molecular formula, C₆₈H₈₈CoN₁₄O₁₄P. What is the percent mass of cobalt in this compound?

Correct Answer
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For the given unbalanced reaction X CaO(s) + y H₂O(l) → z Ca(OH) ₂ The correct stiochiometric coefficients x, y, & z are

Correct Answer
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Tetrasilane (Si₄H₁₀) is a liquid with can react with oxygen to form SiO₂ and water. How many moles of water are produced from each mole of tetrasilane that reacts?

Correct Answer
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Correct Answer
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Correct Answer
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Assume a kernel of wheat has a volume of 8 mm³. How many moles of wheat kernels can fit in the world's largest grain elevator with a capacity of 20 million bushels (1 bushel = 35.24 L) ?

Correct Answer
verified

Correct Answer
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Magnesium will react with carbon dioxide to form magnesium oxide and carbon. 2 Mg(s) + CO₂(g) → 2MgO(s) + C(s) 20) 0 grams of magnesium react completely with excess carbon dioxide. How many grams of solid product should be formed?

Correct Answer
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Correct Answer
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In fermentation, sucrose, C₁₂H₂₂O₁₁, reacts with water to form ethanol, C₂H₅OH, and carbon dioxide. A balanced chemical equation for this reaction is?

Correct Answer
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Correct Answer
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B