Question 1

How many chloride ions are in 1.50 mol of aluminum chloride?

Accepted Answer

A) 2.00 chloride ions 
B) 2.009.023 chloride ions 
C) 9.023 × 1023 chloride ions 
D) 2.71 × 1024 chloride ions 
A) 2.00 chloride ions 
B) 2.009.023 chloride ions 
C) 9.023 × 1023 chloride ions 
D) 2.71 × 1024 chloride ions D

Question 2

Which one of the following contains 38.7% carbon by mass?

Accepted Answer

A) C2H2 
B) CH4 
C) CH3NH2 
D) CO2 
A) C2H2 
B) CH4 
C) CH3NH2 
D) CO2 C

Question 3

How many moles of O2 react with 3.600 mol of Cu2O in the following reaction? 2 Cu2O(s)+ O2(g)→ 4 CuO(s)

Accepted Answer

A) 7.200 mol 
B) 3.600 mol 
C) 1.800 mol 
D) 5.400 mol 
A) 7.200 mol 
B) 3.600 mol 
C) 1.800 mol 
D) 5.400 mol C

Question 4

If the percent yield for the following reaction is 80.0%,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) 10.5 g 
B) 62.5 g 
C) 134 g 
D) 63.0 g 
A) 10.5 g 
B) 62.5 g 
C) 134 g 
D) 63.0 g

Question 5

When the reaction C3H8 + O2 → CO2 + H2O is balanced,the total number of oxygen atoms in the balanced equation is ________.

Accepted Answer

Question 6

Which of the following has the smallest mass?

Accepted Answer

A) 1.40 × 1024 molecules of I2 
B) 340.g of Cl2 
C) 10.0 mol of F2 
D) 0.200 kg of Br2 
A) 1.40 × 1024 molecules of I2 
B) 340.g of Cl2 
C) 10.0 mol of F2 
D) 0.200 kg of Br2

Question 7

Which one of the following is not an empirical formula?

Accepted Answer

A) CHO 
B) CH2O 
C) C3H6O 
D) C8H16O4 
A) CHO 
B) CH2O 
C) C3H6O 
D) C8H16O4

Question 8

What is the mass of a single ozone molecule,O3?

Accepted Answer

A) 2.656 × 10-23 g 
B) 7.969 × 10-22 g 
C) 16.0 g 
D) 48.0 g 
A) 2.656 × 10-23 g 
B) 7.969 × 10-22 g 
C) 16.0 g 
D) 48.0 g

Question 9

What is the empirical formula of a substance that contains 12.0 g of C,2.00 g of H,and 5.33 g of O?

Accepted Answer

A) C3H6O 
B) C15H30O5 
C) C3H5O3 
D) C3H4O4 
A) C3H6O 
B) C15H30O5 
C) C3H5O3 
D) C3H4O4

Question 10

In the combustion analysis of an unknown compound containing only carbon,hydrogen,and oxygen,the grams of oxygen are found from the grams of

Accepted Answer

A) CO2 only. 
B) H2O only. 
C) CO2 and H2O only. 
D) CO2,H2O and unknown compound. 
A) CO2 only. 
B) H2O only. 
C) CO2 and H2O only. 
D) CO2,H2O and unknown compound.

Question 11

Consider the following balanced reaction. 4A + 2B → 2C + D
8.0 moles of A and 30.moles of B react to form 2.5 moles of C.What is the percent yield of this reaction?

Accepted Answer

A) 10% 
B) 62.5% 
C) 83% 
D) 100% 
A) 10% 
B) 62.5% 
C) 83% 
D) 100%

Question 12

What is the molar mass of Co(NO3)2?

Accepted Answer

A) 90 g/mol 
B) 121 g/mol 
C) 152 g/mol 
D) 183 g/mol 
A) 90 g/mol 
B) 121 g/mol 
C) 152 g/mol 
D) 183 g/mol

Question 13

A compound responsible for the odor of garlic has a molecular weight of 146 g/mol.A 0.650 g sample of the compound contains 0.321 g of carbon,0.044 g of hydrogen,and 0.285 g of sulfur.What is the molecular formula of the compound?

Accepted Answer

A) CH5S 
B) C3H5S 
C) C3H15S3 
D) C6H10S2 
A) CH5S 
B) C3H5S 
C) C3H15S3 
D) C6H10S2

Question 14

When 12.00 g of calcium metal is reacted with water,12.00 g of calcium hydroxide is produced.Using the following balanced equation,calculate the percent yield for the reaction? Ca(s)+ 2 H2O(l)→ Ca(OH)2(aq)+ H2(g)

Accepted Answer

A) 27.02% 
B) 54.05% 
C) 100.0% 
D) 30.00% 
A) 27.02% 
B) 54.05% 
C) 100.0% 
D) 30.00%

Question 15

Which contains Avogadro's number of formula units?

Accepted Answer

A) 36.5 g of Cl 
B) 36.5 g of Cl2 
C) 36.5 g of HCl 
D) All of these 
A) 36.5 g of Cl 
B) 36.5 g of Cl2 
C) 36.5 g of HCl 
D) All of these

Question 16

Molecular mass can be determined by

Accepted Answer

A) combustion analysis. 
B) mass spectrometry. 
C) titration. 
D) weighing with an analytical balance. 
A) combustion analysis. 
B) mass spectrometry. 
C) titration. 
D) weighing with an analytical balance.

Question 17

Which of the following statements about mass spectrometry is false?

Accepted Answer

A) Mass spectrometry can be used to determine the molecular weight of a compound. 
B) The curvature of the path in a magnetic field is determined by the mass of the ion. 
C) The paths of heavier ions are deflected more strongly than the paths of lighter ions. 
D) The sample is changed into positively charged ions. 
A) Mass spectrometry can be used to determine the molecular weight of a compound. 
B) The curvature of the path in a magnetic field is determined by the mass of the ion. 
C) The paths of heavier ions are deflected more strongly than the paths of lighter ions. 
D) The sample is changed into positively charged ions.

Question 18

9.0 g of iron is reacted with 9.0 g of water according to the chemical equation shown below.Which one of the following statements is false? 3 Fe(s)+ 4 H2O(l)→ Fe3O4(s)+ 4 H2(g)

Accepted Answer

A) 12.4 g of Fe3O4 are produced. 
B) 5.13 g of H2O are left over. 
C) Mass is conserved in this reaction. 
D) Water is the limiting reactant. 
A) 12.4 g of Fe3O4 are produced. 
B) 5.13 g of H2O are left over. 
C) Mass is conserved in this reaction. 
D) Water is the limiting reactant.

Question 19

Reaction of A (unshaded spheres)with B2 (shaded spheres)is shown schematically in the following diagram.Which equation best describes the stoichiometry of the reaction?

Accepted Answer

A) 4 A + B2 → 8 A2B 
B) 4 A + B2 → A4B2 
C) 16 A + 4 B2 → 8 A2B 
D) 16 A + 4 B2 → 4 A4B2 
A) 4 A + B2 → 8 A2B 
B) 4 A + B2 → A4B2 
C) 16 A + 4 B2 → 8 A2B 
D) 16 A + 4 B2 → 4 A4B2

Question 20

10 g of nitrogen is reacted with 5.0 g 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) 2.8 g of hydrogen are left over. 
B) Hydrogen is the excess reactant. 
C) Nitrogen is the limiting reactant. 
D) The theoretical yield of ammonia is 15 g. 
A) 2.8 g of hydrogen are left over. 
B) Hydrogen is the excess reactant. 
C) Nitrogen is the limiting reactant. 
D) The theoretical yield of ammonia is 15 g.

Exam 3: Mass Relationships in Chemical Reactions

How many chloride ions are in 1.50 mol of aluminum chloride?

Which one of the following contains 38.7% carbon by mass?

How many moles of O2 react with 3.600 mol of Cu2O in the following reaction? 2 Cu2O(s)+ O2(g)→ 4 CuO(s)

If the percent yield for the following reaction is 80.0%,how many grams of KClO3 are needed to produce 42.0 g of O2? 2 KClO3(s)→ 2 KCl(s)+ 3 O2(g)

When the reaction C3H8 + O2 → CO2 + H2O is balanced,the total number of oxygen atoms in the balanced equation is ________.

Which of the following has the smallest mass?

Which one of the following is not an empirical formula?

What is the mass of a single ozone molecule,O3?

What is the empirical formula of a substance that contains 12.0 g of C,2.00 g of H,and 5.33 g of O?

In the combustion analysis of an unknown compound containing only carbon,hydrogen,and oxygen,the grams of oxygen are found from the grams of

Consider the following balanced reaction. 4A + 2B → 2C + D 8.0 moles of A and 30.moles of B react to form 2.5 moles of C.What is the percent yield of this reaction?

What is the molar mass of Co(NO3)2?

A compound responsible for the odor of garlic has a molecular weight of 146 g/mol.A 0.650 g sample of the compound contains 0.321 g of carbon,0.044 g of hydrogen,and 0.285 g of sulfur.What is the molecular formula of the compound?

When 12.00 g of calcium metal is reacted with water,12.00 g of calcium hydroxide is produced.Using the following balanced equation,calculate the percent yield for the reaction? Ca(s)+ 2 H2O(l)→ Ca(OH)2(aq)+ H2(g)

Which contains Avogadro's number of formula units?

Molecular mass can be determined by

Which of the following statements about mass spectrometry is false?

9.0 g of iron is reacted with 9.0 g of water according to the chemical equation shown below.Which one of the following statements is false? 3 Fe(s)+ 4 H2O(l)→ Fe3O4(s)+ 4 H2(g)

Reaction of A (unshaded spheres)with B2 (shaded spheres)is shown schematically in the following diagram.Which equation best describes the stoichiometry of the reaction?

10 g of nitrogen is reacted with 5.0 g 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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Filters

How many moles of O₂ react with 3.600 mol of Cu₂O in the following reaction? 2 Cu₂O(s)+ O₂(g)→ 4 CuO(s)

If the percent yield for the following reaction is 80.0%,how many grams of KClO₃ are needed to produce 42.0 g of O₂? 2 KClO₃(s)→ 2 KCl(s)+ 3 O₂(g)

When the reaction C₃H₈ + O₂ → CO₂ + H₂O is balanced,the total number of oxygen atoms in the balanced equation is ________.

What is the mass of a single ozone molecule,O₃?

What is the molar mass of Co(NO₃)₂?

When 12.00 g of calcium metal is reacted with water,12.00 g of calcium hydroxide is produced.Using the following balanced equation,calculate the percent yield for the reaction? Ca(s)+ 2 H₂O(l)→ Ca(OH)₂(aq)+ H₂(g)

9.0 g of iron is reacted with 9.0 g of water according to the chemical equation shown below.Which one of the following statements is false? 3 Fe(s)+ 4 H₂O(l)→ Fe₃O₄(s)+ 4 H₂(g)

Reaction of A (unshaded spheres)with B₂ (shaded spheres)is shown schematically in the following diagram.Which equation best describes the stoichiometry of the reaction?

10 g of nitrogen is reacted with 5.0 g 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)