Question 1

In combustion analysis, the oxygen content of a substance is equal to the total oxygen in the CO2 and H2O collected in the absorbers.

Accepted Answer

A) True 
 B)False

Question 2

The number of hydrogen atoms in 0.050 mol of C3H8O3 is

Accepted Answer

A)  3.0 × 10 22 H atoms.
B)  1.2 × 10 23 H atoms.
C)  2.4 × 10 23 H atoms.
D)  4.8 × 10 23 H atoms.
E)  None of these choices are correct.F) A) and C)
G) D) and E)

Question 3

Tetraphosphorus hexaoxide ( ℳ = 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) B) and D)
G) D) and E)

Question 4

Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na2SO4.

Accepted Answer

A)  1.244 × 10 23 O atoms
B)  4.976 × 10 23 O atoms
C)  2.409 × 10 24 O atoms
D)  2.915 × 10 24 O atoms
E)  1.166 × 10 25 O atomsF) All of the above
G) D) and E)

Question 5

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) A) and D)
G) A) and E) D

Question 6

Magnesium reacts with iron(III)  chloride to form magnesium chloride (which can be used in fireproofing wood and in disinfectants)  and iron. 3Mg(s)  + 2FeCl3(s)  → 3MgCl2(s)  + 2Fe(s) 
A mixture of 41.0 g of magnesium (ℳ = 24.31 g/mol)  and 175 g of iron(III)  chloride (ℳ = 162.2 g/mol)  is allowed to react. What mass of magnesium chloride (ℳ = 95.21 g/mol)  is formed?

Accepted Answer

A)  68.5 g MgCl 2
B)  77.0 g MgCl 2
C)  71.4 g MgCl 2
D)  107 g MgCl 2
E)  154 g MgCl 2F) B) and D)
G) A) and E)

Question 7

The iodine "clock reaction" involves the following sequence of reactions occurring in a reaction mixture in a single beaker. IO3(aq)  + 5I-(aq)  + 6H+(aq)  → 3I2(aq)  + 3H2O(l) 
I2(aq)  + 2S2O32-(aq)  → 2I-(aq)  + S4O62-(aq) 
The molecular iodine (I2)  formed in reaction 1 is immediately used up in reaction 2, so that no iodine accumulates. In one experiment, a student made up a reaction mixture which initially contained 0.0020 mol of iodate ions (IO3−) . If the iodate ions reacted completely, how many moles of thiosulfate ions (S2O32−)  were needed in reaction 2, in order to react completely with the iodine (I2)  produced in reaction 1?

Accepted Answer

A)  0.0020 mol
B)  0.012 mol
C)  0.0040 mol
D)  0.0010 mol
E)  0.0060 molF) A) and C)
G) C) and D)

Question 8

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

Accepted Answer

A)  9.490 × 10 25 Cr atoms
B)  2.248 × 10 24 Cr atoms
C)  1.124 × 10 24 Cr atoms
D)  3.227 × 10 23 Cr atoms
E)  1.613 × 10 23 Cr atomsF) C) and E)
G) A) and B)

Question 9

Calculate the molar mass of tetraphosphorus decaoxide, P4O10, a corrosive substance which can be used as a drying agent.

Accepted Answer

A)  469.73 g/mol
B)  283.89 g/mol
C)  190.97 g/mol
D)  139.88 g/mol
E)  94.97 g/molF) A) and D)
G) C) and E)

Question 10

Calculate the molar mass of rubidium carbonate, Rb2CO3.

Accepted Answer

A)  340.43 g/mol
B)  255.00 g/mol
C)  230.94 g/mol
D)  145.47 g/mol
E)  113.48 g/molF) A) and B)
G) A) and C)

Question 11

A normal breath takes in about 1.0 L of air. Assuming that air has an average molar mass of 28.8 g, 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 × 10 22
B)  2.2 × 10 22
C)  5.8 × 10 23
D)  1.7 × 10 25
E)  1.8 × 10 25F) B) and D)
G) None of the above

Question 12

How many atoms are in a drop of mercury that has a diameter of 1.0 mm? (Volume of a sphere is 4πr3/3; density of mercury = 13.6 g/cm3)

Accepted Answer

A)  2.1 × 10 19
B)  1.7 × 10 20
C)  2.1 × 10 22
D)  1.7 × 10 23
E)  None of these choices are correct.F) A) and E)
G) A) and C)

Question 13

Hydroxylamine hydrochloride is a powerful reducing agent which is used as a polymerization catalyst. It contains 5.80 mass % H, 20.16 mass % N, 23.02 mass % O, and 51.02 mass % Cl. What is its empirical formula?

Accepted Answer

A)  H 2N 7O 8Cl 18
B)  H 2N 2O 2Cl
C)  HN 3O 4C l9
D)  H 4NOCl
E)  H 4NOCl 2F) A) and E)
G) C) and D)

Question 14

Balance the following equation: Ca3(PO4) 2(s)  + SiO2(s)  + C(s)  → CaSiO3(s)  + CO(g)  + P4(s)

Accepted Answer

A)  Ca 3(PO 4) 2( s) + 3SiO 2( s) + 8C( s) → 3CaSiO 3( s) + 8CO( g) + P4( s) 
B)  Ca 3(PO 4) 2( s) + 3SiO 2( s) + 14C(s) → 3CaSiO 3( s) + 14CO( g) + P 4( s) 
C)  Ca 3(PO 4) 2( s) + 3SiO 2( s) + 8C( s) → 3CaSiO 3( s) + 8CO( g) + 2P 4( s) 
D)  2Ca 3(PO 4) 2( s) + 6SiO 2( s) + 10C( s) → 6CaSiO 3( s) + 10CO( g) + P 4( s) 
E)  2Ca 3(PO 4) 2( s) + 6SiO 2( s) + 10C( s) → 6CaSiO 3( s) + 10CO( g) + 4P 4( s) F) D) and E)
G) A) and C)

Question 15

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

Accepted Answer

A)  B 2O 3( s) + 6HF( l) → 2BF 3( g) + 3H 2O( l) 
B)  B 2O 3( s) + H 6F 6( l) → B 2F 6( g) + H 6O 3( l) 
C)  B 2O 3( s) + 2HF( l) → 2BF 3( g) + H 2O( l) 
D)  B 2O 3( s) + 3HF( l) → 2BF 3( g) + 3H 2O( l) 
E)  B 2O 3( s) + 6HF( l) → 2BF 3( g) + 6H 2O( l) F) A) and E)
G) A) and D)

Question 16

Calculate the mass in grams of 8.35 × 1022 molecules of CBr4.

Accepted Answer

A)  0.0217 g
B)  0.139 g
C)  7.21 g
D)  12.7 g
E)  46.0 gF) None of the above
G) A) and B)

Question 17

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO2 and 0.226 g H2O. What is its empirical formula?

Accepted Answer

A)  C 2H 3O 4
B)  C 3H 4O 2
C)  C 4H 3O 2
D)  C 5H 12O 4
E)  C 2H 2OF) A) and E)
G) B) and D)

Question 18

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)

Question 19

The iodine "clock reaction" involves the following sequence of reactions occurring in a reaction mixture in a single beaker. 1.IO3(aq)  + 5I−(aq)  + 6H+(aq)  → 3I2(aq)  + 3H2O(l) 
2.I2(aq)  + 2S2O32−(aq)  → 2I−(aq)  + S4O62−aq) 
The molecular iodine (I2)  formed in reaction 1 is immediately used up in reaction 2, so that no iodine accumulates. What is the overall reaction occurring in this experiment?

Accepted Answer

A)  IO 3 −( aq) + 3I −( aq) + 2S 2O3 2 − aq) + 6H+( aq) → 2I 2( aq) + S 4O6 2 −( aq) + 3H 2O( l) 
B)  IO 3( aq) + 4S 2O3 2 −( aq) + 6H+( aq) → I −( aq) + 2S 4O6 2 −( aq) + 3H 2O( l) 
C)  IO 3− aq) + 6S 2O3 2 − aq) + 6H+( aq) → I -( aq) + 3S 4O6 2 − aq) + 3H 2O( l) 
D)  IO3 −( aq) + I2( aq) + 8S2O32 −( aq) + 6H+( aq) → 3I-( aq) + 4S4O62 −( aq) + 3H2O( l) 
E)  IO3( aq) + 2I2( aq) + 6S2O32 −(aq) + 6H+( aq) → 5I -( aq) + 3S4O62−( aq) + 3H2O( l) F) B) and C)
G) A) and E) C

Question 20

An important reaction sequence in the industrial production of nitric acid is the following: N2(g)  + 3H2(g)  → 2NH3(g) 
4NH3(g)  + 5O2(g)  → 4NO(g)  + 6H2O(l) 
Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Accepted Answer

A)  12.5 mol O 2
B)  20.0 mol O 2
C)  25.0 mol O 2
D)  50.0 mol O 2
E)  100. mol O 2F) A) and E)
G) None of the above D

Exam 3: Stoichiometry of Formulas and Equations

In combustion analysis, the oxygen content of a substance is equal to the total oxygen in the CO₂ and H₂O collected in the absorbers.

Correct Answer
verified

The number of hydrogen atoms in 0.050 mol of C₃H₈O₃ is

Correct Answer
verified

Tetraphosphorus hexaoxide ( ℳ = 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

Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na₂SO₄.

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
D

Correct Answer
verified

Correct Answer
verified

Potassium dichromate, K₂Cr₂O₇, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K₂Cr₂O₇.

Correct Answer
verified

Calculate the molar mass of tetraphosphorus decaoxide, P₄O₁₀, a corrosive substance which can be used as a drying agent.

Correct Answer
verified

Calculate the molar mass of rubidium carbonate, Rb₂CO₃.

Correct Answer
verified

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

Correct Answer
verified

How many atoms are in a drop of mercury that has a diameter of 1.0 mm? (Volume of a sphere is 4πr³/3; density of mercury = 13.6 g/cm³)

Correct Answer
verified

Hydroxylamine hydrochloride is a powerful reducing agent which is used as a polymerization catalyst. It contains 5.80 mass % H, 20.16 mass % N, 23.02 mass % O, and 51.02 mass % Cl. What is its empirical formula?

Correct Answer
verified

Balance the following equation: Ca₃(PO₄) ₂(s) + SiO₂(s) + C(s) → CaSiO₃(s) + CO(g) + P₄(s)

Correct Answer
verified

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

Correct Answer
verified

Calculate the mass in grams of 8.35 × 10²² molecules of CBr₄.

Correct Answer
verified

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO₂and 0.226 g H₂O. What is its empirical formula?

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

Correct Answer
verified
C

An important reaction sequence in the industrial production of nitric acid is the following: N₂(g) + 3H₂(g) → 2NH₃(g) 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l) Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Correct Answer
verified
D

Exam 3: Stoichiometry of Formulas and Equations

In combustion analysis, the oxygen content of a substance is equal to the total oxygen in the CO2 and H2O collected in the absorbers.

Correct AnswerverifiedShow Answer

The number of hydrogen atoms in 0.050 mol of C3H8O3 is

Correct AnswerverifiedShow Answer

Tetraphosphorus hexaoxide ( ℳ = 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

Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na2SO4.

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 AnswerverifiedD

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Potassium dichromate, K2Cr2O7, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K2Cr2O7.

Correct AnswerverifiedShow Answer

Calculate the molar mass of tetraphosphorus decaoxide, P4O10, a corrosive substance which can be used as a drying agent.

Correct AnswerverifiedShow Answer

Calculate the molar mass of rubidium carbonate, Rb2CO3.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

How many atoms are in a drop of mercury that has a diameter of 1.0 mm? (Volume of a sphere is 4πr3/3; density of mercury = 13.6 g/cm3)

Correct AnswerverifiedShow Answer

Hydroxylamine hydrochloride is a powerful reducing agent which is used as a polymerization catalyst. It contains 5.80 mass % H, 20.16 mass % N, 23.02 mass % O, and 51.02 mass % Cl. What is its empirical formula?

Correct AnswerverifiedShow Answer

Balance the following equation: Ca3(PO4) 2(s) + SiO2(s) + C(s) → CaSiO3(s) + CO(g) + P4(s)

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Calculate the mass in grams of 8.35 × 1022 molecules of CBr4.

Correct AnswerverifiedShow Answer

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO2 and 0.226 g H2O. What is its empirical formula?

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

Correct AnswerverifiedC

An important reaction sequence in the industrial production of nitric acid is the following: N2(g) + 3H2(g) → 2NH3(g) 4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(l) Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Correct AnswerverifiedD

In combustion analysis, the oxygen content of a substance is equal to the total oxygen in the CO₂ and H₂O collected in the absorbers.

Correct Answer
verified

The number of hydrogen atoms in 0.050 mol of C₃H₈O₃ is

Correct Answer
verified

Tetraphosphorus hexaoxide ( ℳ = 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

Calculate the number of oxygen atoms in 29.34 g of sodium sulfate, Na₂SO₄.

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
D

Correct Answer
verified

Correct Answer
verified

Potassium dichromate, K₂Cr₂O₇, is used in tanning leather, decorating porcelain, and water proofing fabrics. Calculate the number of chromium atoms in 78.82 g of K₂Cr₂O₇.

Correct Answer
verified

Calculate the molar mass of tetraphosphorus decaoxide, P₄O₁₀, a corrosive substance which can be used as a drying agent.

Correct Answer
verified

Calculate the molar mass of rubidium carbonate, Rb₂CO₃.

Correct Answer
verified

Correct Answer
verified

How many atoms are in a drop of mercury that has a diameter of 1.0 mm? (Volume of a sphere is 4πr³/3; density of mercury = 13.6 g/cm³)

Correct Answer
verified

Correct Answer
verified

Balance the following equation: Ca₃(PO₄) ₂(s) + SiO₂(s) + C(s) → CaSiO₃(s) + CO(g) + P₄(s)

Correct Answer
verified

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

Correct Answer
verified

Calculate the mass in grams of 8.35 × 10²² molecules of CBr₄.

Correct Answer
verified

Terephthalic acid, used in the production of polyester fibers and films, is composed of carbon, hydrogen, and oxygen. When 0.6943 g of terephthalic acid was subjected to combustion analysis it produced 1.471 g CO₂and 0.226 g H₂O. What is its empirical formula?

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

Correct Answer
verified
C

An important reaction sequence in the industrial production of nitric acid is the following: N₂(g) + 3H₂(g) → 2NH₃(g) 4NH₃(g) + 5O₂(g) → 4NO(g) + 6H₂O(l) Starting from 20.0 mol of nitrogen gas in the first reaction, how many moles of oxygen gas are required in the second one?

Correct Answer
verified
D