Question 1

What is the empirical formula for perfluoropropane if the compound contains 81% fluorine and 19% carbon by mass?

Accepted Answer

A)  CF3
B)  C2F4
C)  C3F8
D)  C6F10E) B) and C)
F) All of the above

Question 2

Which substance is the limiting reactant when 16.0 g of sulfur reacts with 10.0 g of oxygen and 12.0 g of sodium hydroxide according to the following chemical equation? 2 S(s) + 3 O2(g) + 4 NaOH(aq) → 2 Na2SO4(aq) + 2 H2O(l)

Accepted Answer

A)  S(s) 
B)  O2(g) 
C)  NaOH (aq) 
D)  Na2SO4(aq) E) A) and C)
F) C) and D)

Question 3

Tablets of ascorbic acid,or Vitamin C,C6H8O6,are taken as a dietary supplement.If a typical tablet contains 500 mg,how many molecules of Vitamin C are in a tablet?

Accepted Answer

A)  500 molecules
B)  1.71 × 1024 molecules
C)  3.0 × 1024 molecules
D)  1.71 × 1021 moleculesE) A) and B)
F) A) and D)

Question 4

The following diagrams represent the reaction of A2 (shaded spheres) with B2 (unshaded spheres) .Identify the limiting reactant and write a balanced equation for the reaction. 2 (shaded spheres) with B2 (unshaded spheres) .Identify the limiting reactant and write a balanced equation for the reaction.   A) A2 is the limiting reactant;A + 4 B → AB4. B) A2 is the limiting reactant;A2 + 4 B2 → 2 AB4. C) B2 is the limiting reactant;A + 4 B → AB4. D) B2 is the limiting reactant;A2 + 4 B2 → 2 AB4." class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  A2 is the limiting reactant;A + 4 B → AB4.
B)  A2 is the limiting reactant;A2 + 4 B2 → 2 AB4.
C)  B2 is the limiting reactant;A + 4 B → AB4.
D)  B2 is the limiting reactant;A2 + 4 B2 → 2 AB4.E) None of the above
F) All of the above

Question 5

3.0 moles of nitrogen is reacted with 11.0 moles of hydrogen to produce ammonia according to the chemical equation shown below.Which one of the following statements is false? N2(g) + 3 H2(g) → 2 NH3(g)

Accepted Answer

A)  2.0 moles of hydrogen are left over.
B)  Hydrogen is the excess reactant.
C)  Nitrogen is the limiting reactant.
D)  12.0 moles of ammonia are produced.E) A) and B)
F) A) and C)

Question 6

What is the balanced chemical equation for the reaction of element A (unshaded spheres) with element B (shaded spheres) as represented below? 2 → AB3 D) 2A + 3B2 → 2AB3" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  A + B → AB
B)  2A + 3B → 2AB
C)  A + B2 → AB3
D)  2A + 3B2 → 2AB3E) None of the above
F) C) and D)

Question 7

Aluminum metal reacts with aqueous copper(II) sulfate to form aqueous aluminum sulfate and copper metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

Accepted Answer

A)  1
B)  2
C)  3
D)  4E) A) and D)
F) All of the above

Question 8

What is the balanced chemical equation for the reaction of element A (unshaded spheres) with element B (shaded spheres) as represented below? 2 + B2 → A2B D) 2A2 + B2 → 2A2B" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  A + B → AB
B)  4A + 2B → 4AB
C)  A2 + B2 → A2B
D)  2A2 + B2 → 2A2BE) B) and C)
F) A) and D)

Question 9

How many moles of CuO can be produced from 1.80 mol of Cu2O in the following reaction? 2 Cu2O(s) + O2(g) → 4 CuO(s)

Accepted Answer

A)  0.900 mol
B)  1.80 mol
C)  3.60 mol
D)  7.20 molE) C) and D)
F) None of the above

Question 10

When iron(III) oxide reacts with hydrochloric acid,iron(III) chloride and water are formed.How many grams of iron(III) chloride are formed from 10.0 g of iron(III) oxide and 10.0 g of hydrochloric acid?

Accepted Answer

A)  11.1 g
B)  14.8 g
C)  20.3 g
D)  35.1 gE) A) and D)
F) B) and C)

Question 11

Which of the following has the greatest mass?

Accepted Answer

A)  6.0 × 1023 atoms of O
B)  3.0 × 1023 molecules of O2
C)  2.0 × 1023 molecules of O3
D)  All have the same mass.E) All of the above
F) A) and B)

Question 12

If the percent yield for the following reaction is 65.0%,how many grams of KClO3 are needed to produce 42.0 g of O2? 2 KClO3(s) → 2 KCl(s) + 3 O2(g)

Accepted Answer

A)  69.7 g
B)  107 g
C)  165 g
D)  371 gE) None of the above
F) A) and D)

Question 13

What mass of sulfur hexafluoride,SF6,has the same number of fluorine atoms as 50.0 g of oxygen difluoride,OF2?

Accepted Answer

A)  202.7 g
B)  8.33 g
C)  43.0 g
D)  135.1 gE) A) and D)
F) All of the above

Question 14

To the nearest whole number,the molar mass of Cu(NO3)2 is ________ g/mol.

Accepted Answer

Question 15

Hydrazine,N2H4,once used as a rocket propellant,reacts with oxygen in the following equation. N2H4(g) + O2(g) → N2(g) + 2 H2O(g) 
The reaction,at 50% yield,produces 4.0 moles of N2.What was the mass of hydrazine used? Assume that O2 is in excess.

Accepted Answer

A)  32.0 g
B)  260 g
C)  64 g
D)  0.063 gE) A) and D)
F) B) and D)

Question 16

What mass of sulfur hexafluoride,SF6,has the same number of fluorine atoms as 25.0 g of oxygen difluoride,OF2?

Accepted Answer

A)  0.901 g
B)  8.33 g
C)  22.5 g
D)  203 gE) All of the above
F) A) and D)

Question 17

Which of the following has the greatest mass?

Accepted Answer

A)  6.02 × 1023 molecules of Cl2
B)  35.45 g of Cl2
C)  0.500 mol of Cl2
D)  All of these have the same mass.E) None of the above
F) A) and C)

Question 18

What is the balanced chemical equation for the reaction of element A (unshaded spheres) with element B (shaded spheres) as represented below? 2 + B2 → AB3 D) A2 + 3B2 → 2AB3" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)  A + B → AB
B)  A + 3B → 2AB
C)  A2 + B2 → AB3
D)  A2 + 3B2 → 2AB3E) A) and D)
F) B) and C)

Question 19

What is the molar mass of pentane if 4.18 × 1016 molecules of pentane weigh 5.00 μg?

Accepted Answer

A)  72.0 g/mol
B)  139 g/mol
C)  288 g/mol
D)  347 g/molE) B) and C)
F) All of the above

Question 20

What is the mass of a single astatine molecule,At2?

Accepted Answer

A)  3.49 × 10-22 g
B)  6.97 × 10-22 g
C)  210 g
D)  420 gE) C) and D)
F) B) and C)

Exam 3: Mass Relationships in Chemical Reactions

Which of the following has the greatest mass?

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How many moles of CuO can be produced from 1.80 mol of Cu2O in the following reaction? 2 Cu2O(s) + O2(g) → 4 CuO(s)

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3.0 moles of nitrogen is reacted with 11.0 moles of hydrogen to produce ammonia according to the chemical equation shown below.Which one of the following statements is false? N2(g) + 3 H2(g) → 2 NH3(g)

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What is the balanced chemical equation for the reaction of element A (unshaded spheres) with element B (shaded spheres) as represented below?

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What mass of sulfur hexafluoride,SF6,has the same number of fluorine atoms as 50.0 g of oxygen difluoride,OF2?

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Hydrazine,N2H4,once used as a rocket propellant,reacts with oxygen in the following equation. N2H4(g) + O2(g) → N2(g) + 2 H2O(g) The reaction,at 50% yield,produces 4.0 moles of N2.What was the mass of hydrazine used? Assume that O2 is in excess.

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When iron(III) oxide reacts with hydrochloric acid,iron(III) chloride and water are formed.How many grams of iron(III) chloride are formed from 10.0 g of iron(III) oxide and 10.0 g of hydrochloric acid?

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Aluminum metal reacts with aqueous copper(II) sulfate to form aqueous aluminum sulfate and copper metal.What is the stoichiometric coefficient for aluminum when the chemical equation is balanced using the lowest whole-number stoichiometric coefficients?

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Which of the following has the greatest mass?

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What is the mass of a single astatine molecule,At2?

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If the percent yield for the following reaction is 65.0%,how many grams of KClO3 are needed to produce 42.0 g of O2? 2 KClO3(s) → 2 KCl(s) + 3 O2(g)

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What is the empirical formula for perfluoropropane if the compound contains 81% fluorine and 19% carbon by mass?

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What is the balanced chemical equation for the reaction of element A (unshaded spheres) with element B (shaded spheres) as represented below?

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The following diagrams represent the reaction of A2 (shaded spheres) with B2 (unshaded spheres) .Identify the limiting reactant and write a balanced equation for the reaction.

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Tablets of ascorbic acid,or Vitamin C,C6H8O6,are taken as a dietary supplement.If a typical tablet contains 500 mg,how many molecules of Vitamin C are in a tablet?

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What is the molar mass of pentane if 4.18 × 1016 molecules of pentane weigh 5.00 μg?

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To the nearest whole number,the molar mass of Cu(NO3)2 is ________ g/mol.

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Which substance is the limiting reactant when 16.0 g of sulfur reacts with 10.0 g of oxygen and 12.0 g of sodium hydroxide according to the following chemical equation? 2 S(s) + 3 O2(g) + 4 NaOH(aq) → 2 Na2SO4(aq) + 2 H2O(l)

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What is the balanced chemical equation for the reaction of element A (unshaded spheres) with element B (shaded spheres) as represented below?

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What mass of sulfur hexafluoride,SF6,has the same number of fluorine atoms as 25.0 g of oxygen difluoride,OF2?

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How many moles of CuO can be produced from 1.80 mol of Cu₂O in the following reaction? 2 Cu₂O(s) + O₂(g) → 4 CuO(s)

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3.0 moles of nitrogen is reacted with 11.0 moles of hydrogen to produce ammonia according to the chemical equation shown below.Which one of the following statements is false? N₂(g) + 3 H₂(g) → 2 NH₃(g)

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What mass of sulfur hexafluoride,SF₆,has the same number of fluorine atoms as 50.0 g of oxygen difluoride,OF₂?

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Hydrazine,N₂H₄,once used as a rocket propellant,reacts with oxygen in the following equation. N₂H₄(g) + O₂(g) → N₂(g) + 2 H₂O(g) The reaction,at 50% yield,produces 4.0 moles of N₂.What was the mass of hydrazine used? Assume that O₂ is in excess.

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What is the mass of a single astatine molecule,At₂?

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If the percent yield for the following reaction is 65.0%,how many grams of KClO₃ are needed to produce 42.0 g of O₂? 2 KClO₃(s) → 2 KCl(s) + 3 O₂(g)

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The following diagrams represent the reaction of A₂ (shaded spheres) with B₂ (unshaded spheres) .Identify the limiting reactant and write a balanced equation for the reaction.

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Tablets of ascorbic acid,or Vitamin C,C₆H₈O₆,are taken as a dietary supplement.If a typical tablet contains 500 mg,how many molecules of Vitamin C are in a tablet?

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What is the molar mass of pentane if 4.18 × 10¹⁶ molecules of pentane weigh 5.00 μg?

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To the nearest whole number,the molar mass of Cu(NO₃)₂ is ________ g/mol.

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Which substance is the limiting reactant when 16.0 g of sulfur reacts with 10.0 g of oxygen and 12.0 g of sodium hydroxide according to the following chemical equation? 2 S(s) + 3 O₂(g) + 4 NaOH(aq) → 2 Na₂SO₄(aq) + 2 H₂O(l)

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What mass of sulfur hexafluoride,SF₆,has the same number of fluorine atoms as 25.0 g of oxygen difluoride,OF₂?

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