Question 1

Which of the following is the empirical formula for the molecule below?

Accepted Answer

A) CHO 
B) CH3COOH 
C) C2H4O2 
D) CH2O 
E) none of the above. 
A) CHO 
B) CH3COOH 
C) C2H4O2 
D) CH2O 
E) none of the above. D

Question 2

Of the following,the only empirical formula is

Accepted Answer

A) C4H10. 
B) C4H8. 
C) C5H14. 
D) H2O2. 
E) O3. 
A) C4H10. 
B) C4H8. 
C) C5H14. 
D) H2O2. 
E) O3. C

Question 3

A crystal of the mineral troegerite,(UO2)3(AsO4)2 • 12H2O (FM = 1304 amu),contains ____% uranium by mass.

Accepted Answer

A) 18.6 
B) 47.2 
C) 62.8 
D) 30.0 
E) 54.8 
A) 18.6 
B) 47.2 
C) 62.8 
D) 30.0 
E) 54.8 E

Question 4

How many aluminum atoms are there in 52 g of Al2S3?

Accepted Answer

A) 4.2 × 1023 
B) 1.6 × 1021 
C) 2.1 × 1023 
D) 1.1 × 1021 
E) 6.3 × 1023 
A) 4.2 × 1023 
B) 1.6 × 1021 
C) 2.1 × 1023 
D) 1.1 × 1021 
E) 6.3 × 1023

Question 5

The analysis of an organic compound showed that it contained 0.105 mol of C,0.315 mol of H,and 0.0350 mol of N.Its molecular mass is 59 amu.How many atoms of carbon are there in the empirical formula for the compound,and how many are in the molecular formula?

Accepted Answer

A) empirical = 2,molecular = 3 
B) empirical = 3,molecular = 9 
C) empirical = 3,molecular = 3 
D) empirical = 2,molecular = 4 
E) empirical = 5,molecular = 10 
A) empirical = 2,molecular = 3 
B) empirical = 3,molecular = 9 
C) empirical = 3,molecular = 3 
D) empirical = 2,molecular = 4 
E) empirical = 5,molecular = 10

Question 6

A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride:
2Li + F2 → 2LiF.After the reaction is complete,what will be present?

Accepted Answer

A) 0.789 mol of lithium fluoride only 
B) 2.16 mol of lithium fluoride only 
C) 2.16 mol of lithium fluoride and 0.395 mol of fluorine 
D) 0.789 mol of lithium fluoride and 1.37 mol of lithium 
E) none of these 
A) 0.789 mol of lithium fluoride only 
B) 2.16 mol of lithium fluoride only 
C) 2.16 mol of lithium fluoride and 0.395 mol of fluorine 
D) 0.789 mol of lithium fluoride and 1.37 mol of lithium 
E) none of these

Question 7

A 0.0106-mol sample of urea,NH2CONH2,contains

Accepted Answer

A) 6.02 × 1023 molecules. 
B) 2.55 × 1022 molecules. 
C) 5.10 × 1022 atoms. 
D) 2.55 × 1023 atoms. 
E) 1.06 × 1024 atoms. 
A) 6.02 × 1023 molecules. 
B) 2.55 × 1022 molecules. 
C) 5.10 × 1022 atoms. 
D) 2.55 × 1023 atoms. 
E) 1.06 × 1024 atoms.

Question 8

How many atoms are present in 495 g of KPF6 (MM = 184.1 g/mol)?

Accepted Answer

A) 2.38 × 1025 
B) 1.62 × 1021 
C) 2.69 × 1021 
D) 1.21 × 1026 
E) 1.29 × 1025 
A) 2.38 × 1025 
B) 1.62 × 1021 
C) 2.69 × 1021 
D) 1.21 × 1026 
E) 1.29 × 1025

Question 9

The balanced equation for the combustion of ethanol is
2C2H5OH(g)+ 7O2(g)→ 4CO2(g)+ 6H2O(g)
How many grams of dioxygen are required to burn 3.4 g of C2H5OH?

Accepted Answer

A) 8.2 g 
B) 11 g 
C) 2.3 g 
D) 38 g 
E) 57 g 
A) 8.2 g 
B) 11 g 
C) 2.3 g 
D) 38 g 
E) 57 g

Question 10

An organic compound has a molar mass of 169.3 g/mol and contains 10.63 % hydrogen atoms by mass.How many hydrogen atoms are in each molecule of this compound?

Accepted Answer

A) 18 
B) 7 
C) 22 
D) 29 
E) 9 
A) 18 
B) 7 
C) 22 
D) 29 
E) 9

Question 11

Which of the following contains the greatest mass of bromine atoms?

Accepted Answer

A) 15.0 g of KBr 
B) 29.0 g of Br2 
C) 0.096 mol of KBr 
D) 0.078 mol of Br2 
E) 25.0 g of NaBrO3 
A) 15.0 g of KBr 
B) 29.0 g of Br2 
C) 0.096 mol of KBr 
D) 0.078 mol of Br2 
E) 25.0 g of NaBrO3

Question 12

What is the empirical formula of an oxide of nitrogen that contains 25.93 % nitrogen by mass?

Accepted Answer

A) NO2 
B) N2O 
C) N2O3 
D) NO 
E) N2O5 
A) NO2 
B) N2O 
C) N2O3 
D) NO 
E) N2O5

Question 13

In 0.300 mol of dimethylhydrazine,(CH3)2N2H2,there are

Accepted Answer

A) 1.81 × 1024 molecules. 
B) 2.51 × 1023 atoms. 
C) 1.81 × 1022 molecules. 
D) 2.17 × 1024 atoms. 
E) 1.08 × 1024 atoms. 
A) 1.81 × 1024 molecules. 
B) 2.51 × 1023 atoms. 
C) 1.81 × 1022 molecules. 
D) 2.17 × 1024 atoms. 
E) 1.08 × 1024 atoms.

Question 14

If 49.0 g of O2 is mixed with 49.0 g of H2 and the mixture is ignited,what is the maximum mass of water that may be produced?

Accepted Answer

A) 441 g 
B) 55.1 g 
C) 49.0 g 
D) 98 g 
E) 87.1 g 
A) 441 g 
B) 55.1 g 
C) 49.0 g 
D) 98 g 
E) 87.1 g

Question 15

Chlorine was passed over 1.41 g of heated titanium,and 4.54 g of a chloride-containing compound of Ti was obtained.What is the empirical formula of the chloride-containing compound?

Accepted Answer

A) TiCl2 
B) TiCl4 
C) TiCl 
D) TiCl3 
E) Ti2Cl3 
A) TiCl2 
B) TiCl4 
C) TiCl 
D) TiCl3 
E) Ti2Cl3

Question 16

How many molecules are there in 2.10 mg of mannose,C6H12O6,which is a sweet-tasting sugar that has a bitter aftertaste?

Accepted Answer

A) 5.16 × 1021 
B) 2.87 × 1021 
C) 6.32 × 1018 
D) 3.49 × 1024 
E) 7.02 × 1018 
A) 5.16 × 1021 
B) 2.87 × 1021 
C) 6.32 × 1018 
D) 3.49 × 1024 
E) 7.02 × 1018

Question 17

When 20.0 g C2H6 and 60.0 g O2 react to form CO2 and H2O,how many grams of water are formed?

Accepted Answer

A) 14.5 g 
B) 58.0 g 
C) 18.0 g 
D) 20.0 g 
E) none of these 
A) 14.5 g 
B) 58.0 g 
C) 18.0 g 
D) 20.0 g 
E) none of these

Question 18

What is the percentage by mass of chlorine in the insecticide Lindane,C6H6Cl6?

Accepted Answer

A) 20.6 % 
B) 1.00 % 
C) 69.6 % 
D) 8.80 % 
E) 73.1 % 
A) 20.6 % 
B) 1.00 % 
C) 69.6 % 
D) 8.80 % 
E) 73.1 %

Question 19

The reaction of 11.9 g of CHCl3 with excess chlorine produced 11.0 g of CCl4,carbon tetrachloride:
2CHCl3 + 2Cl2 → 2CCl4 + 2HCl
What is the percent yield?

Accepted Answer

A) 92.4 % 
B) 100 % 
C) 71.7 % 
D) 35.9 % 
E) 47.8 % 
A) 92.4 % 
B) 100 % 
C) 71.7 % 
D) 35.9 % 
E) 47.8 %

Question 20

How many molecules are there in 60 g of acetic acid,C2H4O2?

Accepted Answer

A) (6.02 × 1023)/ 60 
B) 60 
C) 6.02 × 1023 
D) 30 
E) 60 × (6.02 × 1023) 
A) (6.02 × 1023)/ 60 
B) 60 
C) 6.02 × 1023 
D) 30 
E) 60 × (6.02 × 1023)

Exam 3: Calculations With Chemical Formulas and Equations

Which of the following is the empirical formula for the molecule below?

Of the following,the only empirical formula is

A crystal of the mineral troegerite,(UO2)3(AsO4)2 • 12H2O (FM = 1304 amu),contains ____% uranium by mass.

How many aluminum atoms are there in 52 g of Al2S3?

The analysis of an organic compound showed that it contained 0.105 mol of C,0.315 mol of H,and 0.0350 mol of N.Its molecular mass is 59 amu.How many atoms of carbon are there in the empirical formula for the compound,and how many are in the molecular formula?

A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride: 2Li + F2 → 2LiF.After the reaction is complete,what will be present?

A 0.0106-mol sample of urea,NH2CONH2,contains

How many atoms are present in 495 g of KPF6 (MM = 184.1 g/mol)?

The balanced equation for the combustion of ethanol is 2C2H5OH(g)+ 7O2(g)→ 4CO2(g)+ 6H2O(g) How many grams of dioxygen are required to burn 3.4 g of C2H5OH?

An organic compound has a molar mass of 169.3 g/mol and contains 10.63 % hydrogen atoms by mass.How many hydrogen atoms are in each molecule of this compound?

Which of the following contains the greatest mass of bromine atoms?

What is the empirical formula of an oxide of nitrogen that contains 25.93 % nitrogen by mass?

In 0.300 mol of dimethylhydrazine,(CH3)2N2H2,there are

If 49.0 g of O2 is mixed with 49.0 g of H2 and the mixture is ignited,what is the maximum mass of water that may be produced?

Chlorine was passed over 1.41 g of heated titanium,and 4.54 g of a chloride-containing compound of Ti was obtained.What is the empirical formula of the chloride-containing compound?

How many molecules are there in 2.10 mg of mannose,C6H12O6,which is a sweet-tasting sugar that has a bitter aftertaste?

When 20.0 g C2H6 and 60.0 g O2 react to form CO2 and H2O,how many grams of water are formed?

What is the percentage by mass of chlorine in the insecticide Lindane,C6H6Cl6?

The reaction of 11.9 g of CHCl3 with excess chlorine produced 11.0 g of CCl4,carbon tetrachloride: 2CHCl3 + 2Cl2 → 2CCl4 + 2HCl What is the percent yield?

How many molecules are there in 60 g of acetic acid,C2H4O2?

Chemistry and Measurement

Atoms, molecules, and Ions

Chemical Reactions

The Gaseous State

Thermochemistry

Quantum Theory of the Atom

Electron Configurations and Periodicity

Ionic and Covalent Bonding

Molecular Geometry and Chemical Bonding Theory

States of Matter; Liquids and Solids

Solutions

Rates of Reaction

Chemical Equilibrium

Acids and Bases

Acid-Base Equilibria

Solubility and Complex-Ion Equilibria

Thermodynamics and Equilibrium

Electrochemistry

Nuclear Chemistry

Chemistry of the Main-Group Metals

The Transition Elements and Coordination Compounds

Organic Chemistry

Polymer Materials: Synthetic and Biological

Filters

A crystal of the mineral troegerite,(UO₂)₃(AsO₄)₂ • 12H₂O (FM = 1304 amu),contains ____% uranium by mass.

How many aluminum atoms are there in 52 g of Al₂S₃?

A 15-g sample of lithium is reacted with 15 g of fluorine to form lithium fluoride: 2Li + F₂ → 2LiF.After the reaction is complete,what will be present?

A 0.0106-mol sample of urea,NH₂CONH₂,contains

How many atoms are present in 495 g of KPF₆ (MM = 184.1 g/mol)?

The balanced equation for the combustion of ethanol is 2C₂H₅OH(g)+ 7O₂(g)→ 4CO₂(g)+ 6H₂O(g) How many grams of dioxygen are required to burn 3.4 g of C₂H₅OH?

In 0.300 mol of dimethylhydrazine,(CH₃)₂N₂H₂,there are

If 49.0 g of O₂ is mixed with 49.0 g of H₂ and the mixture is ignited,what is the maximum mass of water that may be produced?

How many molecules are there in 2.10 mg of mannose,C₆H₁₂O₆,which is a sweet-tasting sugar that has a bitter aftertaste?

When 20.0 g C₂H₆ and 60.0 g O₂ react to form CO₂ and H₂O,how many grams of water are formed?

What is the percentage by mass of chlorine in the insecticide Lindane,C₆H₆Cl₆?

The reaction of 11.9 g of CHCl₃ with excess chlorine produced 11.0 g of CCl₄,carbon tetrachloride: 2CHCl₃ + 2Cl₂ → 2CCl₄ + 2HCl What is the percent yield?

How many molecules are there in 60 g of acetic acid,C₂H₄O₂?