Question 1

Phosphorus pentachloride, PCl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl5.

Accepted Answer

A)   5.38 mol
B)   3.55 mol
C)   0.583 mol
D)   0.282 mol
E)   0.186 molF) A) and B)
G) A) and C)

Question 2

Tetraphosphorus hexaoxide ( 4(s)  + 3O2(g)  → P4O6(s)  If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P4O6, what is the percent yield for the reaction? A)  57.5% B)  48.8% C)  38.0% D)  32.4% E)  16.3%" class="answers-bank-image d-inline" rel="preload" > = 219.9 g/mol)  is formed by the reaction of phosphorus with oxygen gas. P4(s)  + 3O2(g)  → P4O6(s) 
If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P4O6, what is the percent yield for the reaction?

Accepted Answer

A)   57.5%
B)   48.8%
C)   38.0%
D)   32.4%
E)   16.3%F) A) and D)
G) All of the above

Question 3

Sulfur dioxide reacts with chlorine to produce thionyl chloride (used as a drying agent for inorganic halides)  and dichlorine oxide (used as a bleach for wood, pulp, and textiles) . SO2(g)  + 2Cl2(g)  → SOCl2(g)  + Cl2O(g) 
If 0.400 mol of Cl2 reacts with excess SO2, how many moles of Cl2O are formed?

Accepted Answer

A)   0.800 mol
B)   0.400 mol
C)   0.200 mol
D)   0.100 mol
E)   0.0500 molF) A) and B)
G) B) and D)

Question 4

Aluminum metal reacts with chlorine gas to form solid aluminum trichloride, AlCl3. What mass of chlorine gas is needed to react completely with 163 g of aluminum?

Accepted Answer

A)   214 g
B)   245 g
C)   321 g
D)   489 g
E)   643 gF) A) and C)
G) A) and B)

Question 5

Balance the following equation: UO2(s)  + HF(l)  → UF4(s)  + H2O(l)

Accepted Answer

A)   UO2(s)  + 2HF(l)  → UF4(s)  + H2O(l) 
B)   UO2(s)  + 4HF(l)  → UF4(s)  + 2H2O(l) 
C)   UO2(s)  + H4F4(l)  → UF4 (s)  + H4O2(l) 
D)   UO2(s)  + 4HF(l)  → UF4(s)  + 4H2O(l) 
E)   UO2(s)  + 8HF(l)  → 2UF4(s)  + 4H2O(l) F) A) and B)
G) A) and C)

Question 6

A normal breath takes in about 1.0 L of air. Assuming that air has an average molar mass of 28.8g, and that its density is 0.97 g/L, how many molecules of air do you take in with each breath?

Accepted Answer

A)   2.0 × 1022
B)   2.2 × 1022
C)   5.8 × 1023
D)   1.7 × 1025
E)   1.8 × 1025F) All of the above
G) A) and E)

Question 7

Sodium bromate is used in a mixture which dissolves gold from its ores. Calculate the mass in grams of 4.68 mol of sodium bromate.

Accepted Answer

A)   706 g
B)   482 g
C)   383 g
D)   32.2 g
E)   0.0310 gF) C) and E)
G) A) and C)

Question 8

Aluminum oxide (used as an adsorbent or a catalyst for organic reactions)  forms when aluminum reacts with oxygen. 4Al(s)  + 3O2(g)  → 2Al2O3(s) 
A mixture of 82.49 g of aluminum ( 2(g)  → 2Al2O3(s)  A mixture of 82.49 g of aluminum (   = 26.98 g/mol)  and 117.65 g of oxygen (   = 32.00g/mol)  is allowed to react. What mass of aluminum oxide (   = 101.96 g/mol)  can be formed? A)  155.8 g B)  200.2 g C)  249.9 g D)  311.7 g E)  374.9 g" class="answers-bank-image d-inline" rel="preload" > = 26.98 g/mol)  and 117.65 g of oxygen ( 2(g)  → 2Al2O3(s)  A mixture of 82.49 g of aluminum (   = 26.98 g/mol)  and 117.65 g of oxygen (   = 32.00g/mol)  is allowed to react. What mass of aluminum oxide (   = 101.96 g/mol)  can be formed? A)  155.8 g B)  200.2 g C)  249.9 g D)  311.7 g E)  374.9 g" class="answers-bank-image d-inline" rel="preload" > = 32.00g/mol)  is allowed to react. What mass of aluminum oxide ( 2(g)  → 2Al2O3(s)  A mixture of 82.49 g of aluminum (   = 26.98 g/mol)  and 117.65 g of oxygen (   = 32.00g/mol)  is allowed to react. What mass of aluminum oxide (   = 101.96 g/mol)  can be formed? A)  155.8 g B)  200.2 g C)  249.9 g D)  311.7 g E)  374.9 g" class="answers-bank-image d-inline" rel="preload" > = 101.96 g/mol)  can be formed?

Accepted Answer

A)   155.8 g
B)   200.2 g
C)   249.9 g
D)   311.7 g
E)   374.9 gF) A) and C)
G) A) and B)

Question 9

Analysis of a carbohydrate showed that it consisted of 40.0 % C, 6.71 % H, and 53.3 % O by mass. Its molecular mass was found to be between 140 and 160 amu. What is the molecular formula of this compound?

Accepted Answer

A)   C4H8O6
B)   C5H10O5
C)   C5H12O5
D)   C6H12O4
E)   None of these choices are correct.F) C) and D)
G) D) and E)

Question 10

Household sugar, sucrose, has the molecular formula C12H22O11. What is the percent of carbon in sucrose, by mass?

Accepted Answer

A)   26.7%
B)   33.3%
C)   41.4%
D)   42.1%
E)   52.8%F) B) and C)
G) A) and E)

Question 11

Aluminum oxide, Al2O3, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al2O3.

Accepted Answer

A)   2.377 mol
B)   2.146 mol
C)   1.105 mol
D)   0.4660 mol
E)   0.4207 molF) None of the above
G) B) and C)

Question 12

One mole of methane (CH4) contains a total of 3 × 1024 atoms.

Accepted Answer

A) True 
 B)False

Question 13

Balance the following equation: B2O3(s)  + HF(l)  → BF3(g)  + H2O(l)

Accepted Answer

A)   B2O3(s)  + 6HF(l)  → 2BF3(g)  + 3H2O(l) 
B)   B2O3 (s)  + H6F6(l)  → B2F6(g)  + H6O3(l) 
C)   B2O3 (s)  + 2HF(l)  → 2BF3(g)  + H2O(l) 
D)   B2O3 (s)  + 3HF(l)  → 2BF3(g)  + 3H2O(l) 
E)   B2O3 (s)  + 6HF(l)  → 2BF3(g)  + 6H2O(l) F) B) and E)
G) A) and E)

Question 14

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Accepted Answer

A)   BrF
B)   BrF2
C)   Br2F3
D)   Br3F
E)   BrF3F) C) and D)
G) A) and D)

Question 15

Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride.

Accepted Answer

A)   Potassium is the limiting reactant; 2.47 g of chlorine remain.
B)   Potassium is the limiting reactant; 7.23 g of chlorine remain.
C)   Chlorine is the limiting reactant; 4.64 g of potassium remain.
D)   Chlorine is the limiting reactant; 2.70 g of potassium remain.
E)   No limiting reagent: the reactants are present in the correct stoichiometric ratio.F) All of the above
G) B) and E)

Question 16

Which of the following samples has the most moles of the compound?

Accepted Answer

A)   50.0 g of Li2O
B)   75.0 g of CaO
C)   200.0 g of Fe2O3
D)   50.0 g of CO2
E)   100.0 g of SO3F) None of the above
G) D) and E)

Question 17

Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decaoxide and water. PH3(g)  + O2(g)  → P4O10(s)  + H2O(g)  [unbalanced]
Calculate the mass of P4O10(s)  formed when 225 g of PH3 reacts with excess oxygen.

Accepted Answer

A)   1880 g
B)   940. g
C)   900. g
D)   470 g
E)   56.3 gF) C) and D)
G) A) and E)

Question 18

Balance the following equation: C8H18O3(l)  + O2(g)  → H2O(g)  + CO2(g)

Accepted Answer

A)   C8H18O3(l)  + 8O2(g)  → 9H2O(g)  + 8CO2(g) 
B)   C8H18O3(l)  + 11O2(g)  → 9H2O(g)  + 8CO2(g) 
C)   2C8H18O3(l)  + 22O2(g)  → 9H2O(g)  + 16CO2(g) 
D)   C8H18O3(l)  + 13O2(g)  → 18H2O(g)  + 8CO2(g) 
E)   2C8H18O3(l)  + 17O2(g)  → 18H2O(g)  + 16CO2(g) F) B) and C)
G) A) and B)

Question 19

What is the percent yield for the reaction PCl3(g)  + Cl2(g)  → PCl5(g) 
If 119.3 g of PCl5 (M = 208.2 g/mol)  are formed when 61.3 g of Cl2 ( 3(g)  + Cl2(g)  → PCl5(g)  If 119.3 g of PCl5 (M = 208.2 g/mol)  are formed when 61.3 g of Cl2 (   = 70.91 g/mol)  react with excess PCl3? A)  195% B)  85.0% C)  66.3% D)  51.4% E)  43.7%" class="answers-bank-image d-inline" rel="preload" > = 70.91 g/mol)  react with excess PCl3?

Accepted Answer

A)   195%
B)   85.0%
C)   66.3%
D)   51.4%
E)   43.7%F) A) and B)
G) A) and C)

Question 20

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N2(g)  + 3H2(g)  → 2NH3(g) 
How many grams of nitrogen are needed to produce 325 grams of ammonia?

Accepted Answer

A)   1070 g
B)   535 g
C)   267 g
D)   178 g
E)   108 gF) A) and B)
G) B) and D)

Exam 3: Stoichiometry of Formulas and Equations

Aluminum metal reacts with chlorine gas to form solid aluminum trichloride, AlCl₃. What mass of chlorine gas is needed to react completely with 163 g of aluminum?

Correct Answer
verified

Aluminum oxide, Al₂O₃, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al₂O₃.

Correct Answer
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One mole of methane (CH₄) contains a total of 3 × 10²⁴ atoms.

Correct Answer
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Balance the following equation: UO₂(s) + HF(l) → UF₄(s) + H₂O(l)

Correct Answer
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Household sugar, sucrose, has the molecular formula C₁₂H₂₂O₁₁. What is the percent of carbon in sucrose, by mass?

Correct Answer
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Which of the following samples has the most moles of the compound?

Correct Answer
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Correct Answer
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What is the percent yield for the reaction PCl₃(g) + Cl₂(g) → PCl₅(g) If 119.3 g of PCl₅ (M = 208.2 g/mol) are formed when 61.3 g of Cl₂ ( = 70.91 g/mol) react with excess PCl3?

Correct Answer
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Balance the following equation: C₈H₁₈O₃(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
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Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decaoxide and water. PH₃(g) + O₂(g) → P₄O₁₀(s) + H₂O(g) [unbalanced] Calculate the mass of P₄O₁₀(s) formed when 225 g of PH₃ reacts with excess oxygen.

Correct Answer
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Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride.

Correct Answer
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Analysis of a carbohydrate showed that it consisted of 40.0 % C, 6.71 % H, and 53.3 % O by mass. Its molecular mass was found to be between 140 and 160 amu. What is the molecular formula of this compound?

Correct Answer
verified

Phosphorus pentachloride, PCl₅, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl₅.

Correct Answer
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Balance the following equation: B₂O₃(s) + HF(l) → BF₃(g) + H₂O(l)

Correct Answer
verified

Sodium bromate is used in a mixture which dissolves gold from its ores. Calculate the mass in grams of 4.68 mol of sodium bromate.

Correct Answer
verified

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N₂(g) + 3H₂(g) → 2NH₃(g) How many grams of nitrogen are needed to produce 325 grams of ammonia?

Correct Answer
verified

Tetraphosphorus hexaoxide ( = 219.9 g/mol) is formed by the reaction of phosphorus with oxygen gas. P₄(s) + 3O₂(g) → P₄O₆(s) If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P₄O₆, what is the percent yield for the reaction?

Correct Answer
verified

A compound of bromine and fluorine is used to make UF₆, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct Answer
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Correct Answer
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A normal breath takes in about 1.0 L of air. Assuming that air has an average molar mass of 28.8g, and that its density is 0.97 g/L, how many molecules of air do you take in with each breath?

Correct Answer
verified

Exam 3: Stoichiometry of Formulas and Equations

Aluminum metal reacts with chlorine gas to form solid aluminum trichloride, AlCl3. What mass of chlorine gas is needed to react completely with 163 g of aluminum?

Correct AnswerverifiedShow Answer

Aluminum oxide, Al2O3, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al2O3.

Correct AnswerverifiedShow Answer

One mole of methane (CH4) contains a total of 3 × 1024 atoms.

Correct AnswerverifiedShow Answer

Balance the following equation: UO2(s) + HF(l) → UF4(s) + H2O(l)

Correct AnswerverifiedShow Answer

Household sugar, sucrose, has the molecular formula C12H22O11. What is the percent of carbon in sucrose, by mass?

Correct AnswerverifiedShow Answer

Which of the following samples has the most moles of the compound?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

What is the percent yield for the reaction PCl3(g) + Cl2(g) → PCl5(g) If 119.3 g of PCl5 (M = 208.2 g/mol) are formed when 61.3 g of Cl2 ( = 70.91 g/mol) react with excess PCl3?

Correct AnswerverifiedShow Answer

Balance the following equation: C8H18O3(l) + O2(g) → H2O(g) + CO2(g)

Correct AnswerverifiedShow Answer

Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decaoxide and water. PH3(g) + O2(g) → P4O10(s) + H2O(g) [unbalanced] Calculate the mass of P4O10(s) formed when 225 g of PH3 reacts with excess oxygen.

Correct AnswerverifiedShow Answer

Potassium chloride is used as a substitute for sodium chloride for individuals with high blood pressure. Identify the limiting reactant and determine the mass of the excess reactant remaining when 7.00 g of chlorine gas reacts with 5.00 g of potassium to form potassium chloride.

Correct AnswerverifiedShow Answer

Analysis of a carbohydrate showed that it consisted of 40.0 % C, 6.71 % H, and 53.3 % O by mass. Its molecular mass was found to be between 140 and 160 amu. What is the molecular formula of this compound?

Correct AnswerverifiedShow Answer

Phosphorus pentachloride, PCl5, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl5.

Correct AnswerverifiedShow Answer

Balance the following equation: B2O3(s) + HF(l) → BF3(g) + H2O(l)

Correct AnswerverifiedShow Answer

Sodium bromate is used in a mixture which dissolves gold from its ores. Calculate the mass in grams of 4.68 mol of sodium bromate.

Correct AnswerverifiedShow Answer

Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N2(g) + 3H2(g) → 2NH3(g) How many grams of nitrogen are needed to produce 325 grams of ammonia?

Correct AnswerverifiedShow Answer

Tetraphosphorus hexaoxide ( = 219.9 g/mol) is formed by the reaction of phosphorus with oxygen gas. P4(s) + 3O2(g) → P4O6(s) If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P4O6, what is the percent yield for the reaction?

Correct AnswerverifiedShow Answer

A compound of bromine and fluorine is used to make UF6, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A normal breath takes in about 1.0 L of air. Assuming that air has an average molar mass of 28.8g, and that its density is 0.97 g/L, how many molecules of air do you take in with each breath?

Correct AnswerverifiedShow Answer

Aluminum metal reacts with chlorine gas to form solid aluminum trichloride, AlCl₃. What mass of chlorine gas is needed to react completely with 163 g of aluminum?

Correct Answer
verified

Aluminum oxide, Al₂O₃, is used as a filler for paints and varnishes as well as in the manufacture of electrical insulators. Calculate the number of moles in 47.51 g of Al₂O₃.

Correct Answer
verified

One mole of methane (CH₄) contains a total of 3 × 10²⁴ atoms.

Correct Answer
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Balance the following equation: UO₂(s) + HF(l) → UF₄(s) + H₂O(l)

Correct Answer
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Household sugar, sucrose, has the molecular formula C₁₂H₂₂O₁₁. What is the percent of carbon in sucrose, by mass?

Correct Answer
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Correct Answer
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Correct Answer
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What is the percent yield for the reaction PCl₃(g) + Cl₂(g) → PCl₅(g) If 119.3 g of PCl₅ (M = 208.2 g/mol) are formed when 61.3 g of Cl₂ ( = 70.91 g/mol) react with excess PCl3?

Correct Answer
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Balance the following equation: C₈H₁₈O₃(l) + O₂(g) → H₂O(g) + CO₂(g)

Correct Answer
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Phosphine, an extremely poisonous and highly reactive gas, will react with oxygen to form tetraphosphorus decaoxide and water. PH₃(g) + O₂(g) → P₄O₁₀(s) + H₂O(g) [unbalanced] Calculate the mass of P₄O₁₀(s) formed when 225 g of PH₃ reacts with excess oxygen.

Correct Answer
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Correct Answer
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Correct Answer
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Phosphorus pentachloride, PCl₅, a white solid that has a pungent, unpleasant odor, is used as a catalyst for certain organic reactions. Calculate the number of moles in 38.7 g of PCl₅.

Correct Answer
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Balance the following equation: B₂O₃(s) + HF(l) → BF₃(g) + H₂O(l)

Correct Answer
verified

Correct Answer
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Ammonia, an important source of fixed nitrogen that can be metabolized by plants, is produced using the Haber process in which nitrogen and hydrogen combine. N₂(g) + 3H₂(g) → 2NH₃(g) How many grams of nitrogen are needed to produce 325 grams of ammonia?

Correct Answer
verified

Tetraphosphorus hexaoxide ( = 219.9 g/mol) is formed by the reaction of phosphorus with oxygen gas. P₄(s) + 3O₂(g) → P₄O₆(s) If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P₄O₆, what is the percent yield for the reaction?

Correct Answer
verified

A compound of bromine and fluorine is used to make UF₆, which is an important chemical in processing and reprocessing of nuclear fuel. The compound contains 58.37 mass percent bromine. Determine its empirical formula.

Correct Answer
verified

Correct Answer
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Correct Answer
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