Question 1

Lithium metal reacts with nitrogen gas to form lithium nitride.Identify the balanced reaction that describes this process.

Accepted Answer

A)  Li + N  →\rarr→  LiN
B)  Li + N2  →\rarr→ LiN2
C)  2Li + N2  →\rarr→ Li2N2
D)  6Li + N2  →\rarr→  2Li3N
E)  2Li + N2  →\rarr→ 2LiN F) None of the above
G) B) and E)

Question 2

What is the average mass of one Ca atom?

Accepted Answer

A)  40.08 amu
B)  40.08 g
C)  40.08 g/mol
D)  2.41 x 10-21 amu
E)  2.41x1025 gF) A) and B)
G) None of the above

Question 3

Refer to the (unbalanced)equation CS2 + CaO $\rarr$CO2 + CaS.How many grams of CaO are required to react completely with 38 g of CS2?

Accepted Answer

Question 4

What is the coefficient for O2 when the following combustion reaction of a hydrocarbon is balanced?
 ___ C7H14 + ___ O2  →\rarr→  ___ CO2 + ___ H2O

Accepted Answer

A)  42
B)  21
C)  11
D)  10
E)  none of these F) D) and E)
G) A) and D)

Question 5

Calculate the mass of 3.00 moles of CF2Cl2.

Accepted Answer

A)  3.00 g
B)  174 g
C)  363 g
D)  1.81 × 1024 g
E)  40.3 gF) B) and C)
G) A) and B)

Question 6

A chemistry student determined the empirical formula for tungsten oxide (WxOy).To do so, he heated tungsten with oxygen in a crucible.The data that he recorded are shown below:  What is the empirical formula of tungsten oxide?

Accepted Answer

Question 7

What is the theoretical yield of vanadium, in moles, that can be produced by the reaction of 1.0 mole of V2O5 with 4.0 moles of calcium based on the following chemical reaction? V2O5(s) + 5Ca(l)  →\rarr→  2V(l) + 5CaO(s)

Accepted Answer

A)  1.0 mol
B)  1.6 mol
C)  2.0 mol
D)  0.80 mol
E)  None of these F) A) and D)
G) C) and D)

Question 8

An average atom of uranium (U) is approximately how many times heavier than an atom of potassium?

Accepted Answer

A)  6.1 times
B)  4.8 times
C)  2.4 times
D)  12.5 times
E)  7.7 timesF) B) and D)
G) A) and C)

Question 9

Hydrogen chloride gas can be prepared by the following reaction: 
2NaCl(s) + H2SO4(aq)  →\rarr→  2HCl(g) + Na2SO4(s) 
How many grams of HCl can be prepared from 2.00 mol H2SO4 and 2.56 mol NaCl?

Accepted Answer

A)  7.30 g
B)  93.3 g
C)  146 g
D)  150 g
E)  196 g F) A) and C)
G) A) and B)

Question 10

A silver wire has a diameter of 0.500 mm.What length of this wire contains exactly 1.00 mol of silver? (density of Ag = 10.5 g/cm3)

Accepted Answer

A)  52.3 m
B)  222 m
C)  13.1 m
D)  2.01 m
E)  890 mF) All of the above
G) A) and E)

Question 11

Phosphorus pentachloride reacts with water to form hydrochloric acid and phosphoric acid.How many total moles of acid are formed when starting with 4.5 g of PCl5 and excess H2O? PCl5 + 4H2O  →\rarr→ 5HCl + H3PO4

Accepted Answer

A)  0.022 moles
B)  0.12 moles
C)  0.13 moles
D)  27 moles
E)  23 moles F) B) and C)
G) B) and D)

Question 12

Which one of the following is an example of a balanced chemical reaction?

Accepted Answer

A)  C3H6O + 4O2  →\rarr→ 3CO2 + 3H2O
B)  2C3H6O + 9O2  →\rarr→ 6CO2 + 6H2O
C)  C3H6O + 3O2  →\rarr→ 3CO2 + 3H2O
D)  2C3H6O + 9O2  →\rarr→ 6CO2 + 3H2O
E)  C3H6O + 9O2  →\rarr→  3CO2 + 3H2O F) B) and C)
G) A) and D)

Question 13

A compound was discovered whose composition by mass is 85.6% C and 14.4% H.Which of the following could be the molecular formula of this compound?

Accepted Answer

A)  CH4
B)  C2H4
C)  C3H4
D)  C2H6
E)  C3H8F) C) and E)
G) B) and E)

Question 14

A sample of iron metal is placed in a graduated cylinder.It is noted that 10.4 mL of water is displaced by the iron.The iron is then reacted with excess hydrochloric acid to produce iron (II) chloride and hydrogen gas.Given the density for iron is 7.86 g/mL, how many grams of iron (II) chloride are produced in the reaction? 
Fe(s) + 2HCl(aq)  →\rarr→ FeCl2(aq) + H2(g)

Accepted Answer

A)  23.6 g
B)  47.2 g
C)  185 g
D)  3.00 g
E)  81.7 g F) B) and D)
G) C) and E)

Question 15

Boron obtained from borax deposits in Death Valley consists of two isotopes.They are boron-10 and boron-11 with atomic masses of 10.013 amu and 11.009 amu, respectively.The atomic mass of boron is 10.81 amu (see periodic table) .Which isotope of boron is more abundant, boron-10 or boron-11?

Accepted Answer

A)  Cannot be determined from data given
B)  Neither, their abundances are the same.
C)  Boron-10
D)  Boron-11E) B) and C)
F) All of the above

Question 16

What is the mass of 0.0250 mol of P2O5?

Accepted Answer

A)  35.5 g
B)  5676 g
C)  0.0250 g
D)  1.51 × 1022 g
E)  3.55 gF) A) and C)
G) D) and E)

Question 17

When balanced the coefficient of O2 in the following equation is 
__ C2H4 + __ O2  →\rarr→  __ CO2 + __ H2O

Accepted Answer

A)  1.
B)  2.
C)  3.
D)  4.
E)  6. F) A) and B)
G) C) and D)

Question 18

Formaldehyde has the formula CH2O.How many molecules are there in 0.11 g of formaldehyde?

Accepted Answer

A)  6.1 × 10-27
B)  3.7 × 10-3
C)  4.0
D)  2.2 × 1021
E)  6.6 × 1022F) C) and D)
G) A) and E)

Question 19

How many O atoms are in 4.39 g of CO2?

Accepted Answer

A)  5.29 x 1024 O atoms
B)  1.03 x 1022 O atoms
C)  1.65 x 1023 O atoms
D)  6.01 x 1022 O atoms
E)  1.20 x 1023 O atomsF) All of the above
G) B) and C)

Question 20

Phosphorus reacts with iodine as shown in the chemical reaction below.What is the percent yield of the reaction if 28.2 g PI3 is obtained from the reaction of 48.0 g of I2 with excess phosphorus?
2P(s)+ 3I2(s)$\rarr$2PI3(s)

Accepted Answer

Exam 3: Mass Relationships in Chemical Reactions

Which one of the following is an example of a balanced chemical reaction?

Correct Answer
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How many O atoms are in 4.39 g of CO₂?

Correct Answer
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What is the theoretical yield of vanadium, in moles, that can be produced by the reaction of 1.0 mole of V₂O₅ with 4.0 moles of calcium based on the following chemical reaction? V₂O₅(s) + 5Ca(l) $\rarr$ 2V(l) + 5CaO(s)

Correct Answer
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What is the coefficient for O₂ when the following combustion reaction of a hydrocarbon is balanced? _ C₇H₁₄ + _ O₂ $\rarr$ _ CO₂ + _ H₂O

Correct Answer
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Correct Answer
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Boron obtained from borax deposits in Death Valley consists of two isotopes.They are boron-10 and boron-11 with atomic masses of 10.013 amu and 11.009 amu, respectively.The atomic mass of boron is 10.81 amu (see periodic table) .Which isotope of boron is more abundant, boron-10 or boron-11?

Correct Answer
verified

Phosphorus pentachloride reacts with water to form hydrochloric acid and phosphoric acid.How many total moles of acid are formed when starting with 4.5 g of PCl₅ and excess H₂O? PCl₅ + 4H₂O $\rarr$ 5HCl + H₃PO₄

Correct Answer
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A compound was discovered whose composition by mass is 85.6% C and 14.4% H.Which of the following could be the molecular formula of this compound?

Correct Answer
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Formaldehyde has the formula CH₂O.How many molecules are there in 0.11 g of formaldehyde?

Correct Answer
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Calculate the mass of 3.00 moles of CF₂Cl₂.

Correct Answer
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Phosphorus reacts with iodine as shown in the chemical reaction below.What is the percent yield of the reaction if 28.2 g PI₃ is obtained from the reaction of 48.0 g of I₂ with excess phosphorus? 2P(s)+ 3I₂(s) $\rarr$ 2PI₃(s)

Correct Answer
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A silver wire has a diameter of 0.500 mm.What length of this wire contains exactly 1.00 mol of silver? (density of Ag = 10.5 g/cm³)

Correct Answer
verified

Hydrogen chloride gas can be prepared by the following reaction: 2NaCl(s) + H₂SO₄(aq) $\rarr$ 2HCl(g) + Na₂SO₄(s) How many grams of HCl can be prepared from 2.00 mol H₂SO₄ and 2.56 mol NaCl?

Correct Answer
verified

A chemistry student determined the empirical formula for tungsten oxide (W_xO_y).To do so, he heated tungsten with oxygen in a crucible.The data that he recorded are shown below: What is the empirical formula of tungsten oxide?

Correct Answer
verified

Refer to the (unbalanced)equation CS₂ + CaO $\rarr$ CO₂ + CaS.How many grams of CaO are required to react completely with 38 g of CS₂?

Correct Answer
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When balanced the coefficient of O₂ in the following equation is C₂H₄ + O₂ $\rarr$ CO₂ + H₂O

Correct Answer
verified

An average atom of uranium (U) is approximately how many times heavier than an atom of potassium?

Correct Answer
verified

What is the mass of 0.0250 mol of P₂O₅?

Correct Answer
verified

Lithium metal reacts with nitrogen gas to form lithium nitride.Identify the balanced reaction that describes this process.

Correct Answer
verified

What is the average mass of one Ca atom?

Correct Answer
verified

Exam 3: Mass Relationships in Chemical Reactions

Which one of the following is an example of a balanced chemical reaction?

Correct AnswerverifiedShow Answer

How many O atoms are in 4.39 g of CO2?

Correct AnswerverifiedShow Answer

What is the theoretical yield of vanadium, in moles, that can be produced by the reaction of 1.0 mole of V2O5 with 4.0 moles of calcium based on the following chemical reaction? V2O5(s) + 5Ca(l) →\rarr→ 2V(l) + 5CaO(s)

Correct AnswerverifiedShow Answer

What is the coefficient for O2 when the following combustion reaction of a hydrocarbon is balanced? ___ C7H14 + ___ O2 →\rarr→ ___ CO2 + ___ H2O

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Boron obtained from borax deposits in Death Valley consists of two isotopes.They are boron-10 and boron-11 with atomic masses of 10.013 amu and 11.009 amu, respectively.The atomic mass of boron is 10.81 amu (see periodic table) .Which isotope of boron is more abundant, boron-10 or boron-11?

Correct AnswerverifiedShow Answer

Phosphorus pentachloride reacts with water to form hydrochloric acid and phosphoric acid.How many total moles of acid are formed when starting with 4.5 g of PCl5 and excess H2O? PCl5 + 4H2O →\rarr→ 5HCl + H3PO4

Correct AnswerverifiedShow Answer

A compound was discovered whose composition by mass is 85.6% C and 14.4% H.Which of the following could be the molecular formula of this compound?

Correct AnswerverifiedShow Answer

Formaldehyde has the formula CH2O.How many molecules are there in 0.11 g of formaldehyde?

Correct AnswerverifiedShow Answer

Calculate the mass of 3.00 moles of CF2Cl2.

Correct AnswerverifiedShow Answer

Phosphorus reacts with iodine as shown in the chemical reaction below.What is the percent yield of the reaction if 28.2 g PI3 is obtained from the reaction of 48.0 g of I2 with excess phosphorus? 2P(s)+ 3I2(s) →\rarr→ 2PI3(s)

Correct AnswerverifiedShow Answer

A silver wire has a diameter of 0.500 mm.What length of this wire contains exactly 1.00 mol of silver? (density of Ag = 10.5 g/cm3)

Correct AnswerverifiedShow Answer

Hydrogen chloride gas can be prepared by the following reaction: 2NaCl(s) + H2SO4(aq) →\rarr→ 2HCl(g) + Na2SO4(s) How many grams of HCl can be prepared from 2.00 mol H2SO4 and 2.56 mol NaCl?

Correct AnswerverifiedShow Answer

A chemistry student determined the empirical formula for tungsten oxide (WxOy).To do so, he heated tungsten with oxygen in a crucible.The data that he recorded are shown below: What is the empirical formula of tungsten oxide?

Correct AnswerverifiedShow Answer

Refer to the (unbalanced)equation CS2 + CaO →\rarr→ CO2 + CaS.How many grams of CaO are required to react completely with 38 g of CS2?

Correct AnswerverifiedShow Answer

When balanced the coefficient of O2 in the following equation is __ C2H4 + __ O2 →\rarr→ __ CO2 + __ H2O

Correct AnswerverifiedShow Answer

An average atom of uranium (U) is approximately how many times heavier than an atom of potassium?

Correct AnswerverifiedShow Answer

What is the mass of 0.0250 mol of P2O5?

Correct AnswerverifiedShow Answer

Lithium metal reacts with nitrogen gas to form lithium nitride.Identify the balanced reaction that describes this process.

Correct AnswerverifiedShow Answer

What is the average mass of one Ca atom?

Correct AnswerverifiedShow Answer

Correct Answer
verified

How many O atoms are in 4.39 g of CO₂?

Correct Answer
verified

What is the theoretical yield of vanadium, in moles, that can be produced by the reaction of 1.0 mole of V₂O₅ with 4.0 moles of calcium based on the following chemical reaction? V₂O₅(s) + 5Ca(l) $\rarr$ 2V(l) + 5CaO(s)

Correct Answer
verified

What is the coefficient for O₂ when the following combustion reaction of a hydrocarbon is balanced? _ C₇H₁₄ + _ O₂ $\rarr$ _ CO₂ + _ H₂O

Correct Answer
verified

Correct Answer
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Correct Answer
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Phosphorus pentachloride reacts with water to form hydrochloric acid and phosphoric acid.How many total moles of acid are formed when starting with 4.5 g of PCl₅ and excess H₂O? PCl₅ + 4H₂O $\rarr$ 5HCl + H₃PO₄

Correct Answer
verified

Correct Answer
verified

Formaldehyde has the formula CH₂O.How many molecules are there in 0.11 g of formaldehyde?

Correct Answer
verified

Calculate the mass of 3.00 moles of CF₂Cl₂.

Correct Answer
verified

Phosphorus reacts with iodine as shown in the chemical reaction below.What is the percent yield of the reaction if 28.2 g PI₃ is obtained from the reaction of 48.0 g of I₂ with excess phosphorus? 2P(s)+ 3I₂(s) $\rarr$ 2PI₃(s)

Correct Answer
verified

A silver wire has a diameter of 0.500 mm.What length of this wire contains exactly 1.00 mol of silver? (density of Ag = 10.5 g/cm³)

Correct Answer
verified

Hydrogen chloride gas can be prepared by the following reaction: 2NaCl(s) + H₂SO₄(aq) $\rarr$ 2HCl(g) + Na₂SO₄(s) How many grams of HCl can be prepared from 2.00 mol H₂SO₄ and 2.56 mol NaCl?

Correct Answer
verified

A chemistry student determined the empirical formula for tungsten oxide (W_xO_y).To do so, he heated tungsten with oxygen in a crucible.The data that he recorded are shown below: What is the empirical formula of tungsten oxide?

Correct Answer
verified

Refer to the (unbalanced)equation CS₂ + CaO $\rarr$ CO₂ + CaS.How many grams of CaO are required to react completely with 38 g of CS₂?

Correct Answer
verified

When balanced the coefficient of O₂ in the following equation is C₂H₄ + O₂ $\rarr$ CO₂ + H₂O

Correct Answer
verified

Correct Answer
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What is the mass of 0.0250 mol of P₂O₅?

Correct Answer
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Correct Answer
verified

Correct Answer
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