Question 1

How many chlorine atoms are there in 16.0 g of carbon tetrachloride (CCl4)?

Accepted Answer

A) 6.91   1025 
B) 1.04   10-1 
C) 6.26   1022 
D) 2.51   1023 
E) 4.23   1017 
A) 6.91   1025 
B) 1.04   10-1 
C) 6.26   1022 
D) 2.51   1023 
E) 4.23   1017

Question 2

A tiny speck (8.3   10-7 mol) of radioactive americium-241 is used in smoke detectors. How many atoms of americium-241 are there in one of these smoke detectors?

Accepted Answer

A) 5.0   1017 
B) 1.2   1020 
C) 2.9   1022 
D) 6.0   1023 
E) 8.3   107 
A) 5.0   1017 
B) 1.2   1020 
C) 2.9   1022 
D) 6.0   1023 
E) 8.3   107

Question 3

Write a definition of the phrase "stoichiometry of a chemical reaction."

Accepted Answer

"Stoichiometry of a chemical r

Question 4

Which substance listed below contains the most oxygen atoms?

Accepted Answer

A) 1 mol of Al2O3 
B) 1 mol of Fe2O3 
C) 2 mol of N2O4 
D) 2 mol of CO2 
E) 2 mol of HNO3 
A) 1 mol of Al2O3 
B) 1 mol of Fe2O3 
C) 2 mol of N2O4 
D) 2 mol of CO2 
E) 2 mol of HNO3

Question 5

What is the formula mass of (NH4)3PO4 (ammonium phosphate)?

Accepted Answer

A) 62.0 g/mol 
B) 113 g/mol 
C) 131 g/mol 
D) 149 g/mol 
E) 303 g/mol 
A) 62.0 g/mol 
B) 113 g/mol 
C) 131 g/mol 
D) 149 g/mol 
E) 303 g/mol

Question 6

Which molecules shown below have the same empirical formula?

Accepted Answer

A) II, III, and IV are the same. 
B) Only II and III are the same. 
C) Only I and III are the same. 
D) I, II, and III are the same. 
E) I and III are the same, and II and IV are the same. 
A) II, III, and IV are the same. 
B) Only II and III are the same. 
C) Only I and III are the same. 
D) I, II, and III are the same. 
E) I and III are the same, and II and IV are the same.

Question 7

One form of asbestos called chrysotile is considered to be a human carcinogen. Mass analysis shows that the composition of chrysotile is 26.3% Mg, 20.2% Si, 1.45% H, and the remainder of the mass is oxygen. Determine the empirical formula of chrysotile.

Accepted Answer

A) MgSiHO3 
B) Mg2Si2H2O5 
C) Mg3Si2H4O6 
D) Mg3Si2H4O9 
E) Mg4Si3H5O9 
A) MgSiHO3 
B) Mg2Si2H2O5 
C) Mg3Si2H4O6 
D) Mg3Si2H4O9 
E) Mg4Si3H5O9

Question 8

Carbon monoxide is used in refining iron ore to produce the metal. Assuming the reaction yield is 100%, how many grams of iron would be produced if 5.00 mol of carbon monoxide were exposed to 800 g iron(III) oxide?
Fe2O3(s)   3CO(g)   2Fe(s)   3CO2(g)

Accepted Answer

The answer of Carbon monoxide is used in refining iron...

Question 9

Chlorhexidine is an antibacterial drug found in mouthwash and has an elemental analysis of 52.28% carbon, 5.98% hydrogen, 14.03% chlorine, and 27.71% nitrogen. It has a molar mass of 505.45 g/mol. What is the molecular formula of chlorhexidine?

Accepted Answer

A) C11H15ClN5 
B) C22H30Cl2N10 
C) C10H15ClN6 
D) C20H30Cl2N12 
E) C30H45Cl3N18 
A) C11H15ClN5 
B) C22H30Cl2N10 
C) C10H15ClN6 
D) C20H30Cl2N12 
E) C30H45Cl3N18

Question 10

Ozone (O3) reacts with iodide (I-) and water to form iodine (I2), hydroxide (OH-), and oxygen (O2). Balance the following reaction equation and report the sum of the stoichiometric coefficients. O3   I-  H2O   I2   OH-  O2

Accepted Answer

A) 10 
B) 6 
C) 8 
D) 12 
E) 14 
A) 10 
B) 6 
C) 8 
D) 12 
E) 14

Question 11

One mole is defined as ________

Accepted Answer

A) the number of particles equal to the number of atoms in exactly 12 g of carbon-12. 
B) the number of particles equal to the number of atoms in exactly 16 g of oxygen-16. 
C) exactly 6.02   1022 particles. 
D) the number of particles equal to the number of atoms in exactly 1 g of hydrogen-1. 
E) the number of particles equal to the number of atoms in exactly 1 kg of carbon in a vault at the National Bureau of Standards. 
A) the number of particles equal to the number of atoms in exactly 12 g of carbon-12. 
B) the number of particles equal to the number of atoms in exactly 16 g of oxygen-16. 
C) exactly 6.02   1022 particles. 
D) the number of particles equal to the number of atoms in exactly 1 g of hydrogen-1. 
E) the number of particles equal to the number of atoms in exactly 1 kg of carbon in a vault at the National Bureau of Standards.

Question 12

Combustion analysis of an organic compound to determine the percentages of carbon, hydrogen, and oxygen in the compound depends on which of the following assumptions?

Accepted Answer

A) The compound burns completely to form carbon dioxide and water. 
B) All the oxygen in the products comes from the added oxygen gas. 
C) The mass of the carbon dioxide produced equals the mass of the carbon in the sample. 
D) The moles of water produced equal the moles of hydrogen in the sample. 
E) The mass of oxygen in the sample is the difference between the mass of the sample and the sum of the masses of carbon dioxide and water produced. 
A) The compound burns completely to form carbon dioxide and water. 
B) All the oxygen in the products comes from the added oxygen gas. 
C) The mass of the carbon dioxide produced equals the mass of the carbon in the sample. 
D) The moles of water produced equal the moles of hydrogen in the sample. 
E) The mass of oxygen in the sample is the difference between the mass of the sample and the sum of the masses of carbon dioxide and water produced.

Question 13

How many oxygen atoms are there in 27.0 g of sodium sulfate (Na2SO4)?

Accepted Answer

A) 1.15   1023 atoms 
B) 4.58   1023 atoms 
C) 5.73   1023 atoms 
D) 2.41   1024 atoms 
E) 6.88   1023 atoms 
A) 1.15   1023 atoms 
B) 4.58   1023 atoms 
C) 5.73   1023 atoms 
D) 2.41   1024 atoms 
E) 6.88   1023 atoms

Question 14

Elemental analysis of the organic compound meta-xylene shows that it is 9.49% H and 90.51% C by mass. What is the empirical formula of this hydrocarbon?

Accepted Answer

A) CH 
B) C2H3 
C) C3H4 
D) C4H5 
E) C5H6 
A) CH 
B) C2H3 
C) C3H4 
D) C4H5 
E) C5H6

Question 15

Which statement A-D regarding the terms mole and molar mass is not correct?

Accepted Answer

A) A mole is defined as the number of particles in exactly 12 g of carbon-12. 
B) A mole of oxygen gas contains 6.022   1023 molecules. 
C) Two moles of oxygen atoms can be obtained by decomposing one mole of carbon dioxide. 
D) To obtain the molar mass in grams (g/mol) from the atomic mass in atomic mass units(u), multiply by 6.022   1023/mol and divide by 6.022   1023 u/g. 
E) Statements A-D all are correct. 
A) A mole is defined as the number of particles in exactly 12 g of carbon-12. 
B) A mole of oxygen gas contains 6.022   1023 molecules. 
C) Two moles of oxygen atoms can be obtained by decomposing one mole of carbon dioxide. 
D) To obtain the molar mass in grams (g/mol) from the atomic mass in atomic mass units(u), multiply by 6.022   1023/mol and divide by 6.022   1023 u/g. 
E) Statements A-D all are correct.

Question 16

Air bags in cars inflate when an electrical spark activates sodium azide (NaN3) so that it decomposes to sodium metal, Na, and nitrogen gas, N2. In the balanced reaction equation, how many moles of nitrogen gas are formed for each mole of sodium azide?

Accepted Answer

A) 1 
B) 1.5 
C) 2 
D) 3 
E) 2.5 
A) 1 
B) 1.5 
C) 2 
D) 3 
E) 2.5

Question 17

Allicin, a potent antibacterial compound, is formed by the enzyme alliinase when garlic is chopped or damaged. Allicin contains carbon, hydrogen, oxygen, and sulfur atoms. In combustion analysis, a 10.00 mg sample of allicin produced 16.27 mg of CO2, 5.55 mg of water, and 7.90 mg of SO2. What is the empirical formula of allicin?

Accepted Answer

A) C6H10S2O 
B) C3H5SO 
C) C12H20S4O 
D) C6H10SO 
E) The moles of oxygen in the sample cannot be determined, so the empirical formula cannot be determined. 
A) C6H10S2O 
B) C3H5SO 
C) C12H20S4O 
D) C6H10SO 
E) The moles of oxygen in the sample cannot be determined, so the empirical formula cannot be determined.

Question 18

What is the difference in the chemistry between photosynthesis and respiration?

Accepted Answer

In photosynthesis carbon dioxi

Question 19

How many moles of ammonia are there in a 346 g sample of pure NH3 (17.03 g/mol)?

Accepted Answer

A) 0.0496 mol 
B) 20.3 mol 
C) 24.7 mol 
D) 5,930 mol 
E) 3.46 mol 
A) 0.0496 mol 
B) 20.3 mol 
C) 24.7 mol 
D) 5,930 mol 
E) 3.46 mol

Question 20

The combustion of fossil fuels is the main anthropogenic source of carbon dioxide in the atmosphere. During the combustion of gasoline in automobile engines, oxygen reacts with hydrocarbons to produce carbon dioxide and water. Assume gasoline is octane (C8H18). Write the balanced reaction equation, and report the sum of the stoichiometric coefficients written as integers.

Accepted Answer

A) 55 
B) 29 
C) 31 
D) 30 
E) 61 
A) 55 
B) 29 
C) 31 
D) 30 
E) 61

How many chlorine atoms are there in 16.0 g of carbon tetrachloride (CCl₄)?

A tiny speck (8.3 10^-7 mol) of radioactive americium-241 is used in smoke detectors. How many atoms of americium-241 are there in one of these smoke detectors?

Write a definition of the phrase "stoichiometry of a chemical reaction."

Which substance listed below contains the most oxygen atoms?

What is the formula mass of (NH₄)₃PO₄ (ammonium phosphate)?

Which molecules shown below have the same empirical formula?

One form of asbestos called chrysotile is considered to be a human carcinogen. Mass analysis shows that the composition of chrysotile is 26.3% Mg, 20.2% Si, 1.45% H, and the remainder of the mass is oxygen. Determine the empirical formula of chrysotile.

Carbon monoxide is used in refining iron ore to produce the metal. Assuming the reaction yield is 100%, how many grams of iron would be produced if 5.00 mol of carbon monoxide were exposed to 800 g iron(III) oxide? Fe₂O₃(s) 3CO(g) 2Fe(s) 3CO₂(g)

Chlorhexidine is an antibacterial drug found in mouthwash and has an elemental analysis of 52.28% carbon, 5.98% hydrogen, 14.03% chlorine, and 27.71% nitrogen. It has a molar mass of 505.45 g/mol. What is the molecular formula of chlorhexidine?

Ozone (O₃) reacts with iodide (I^-) and water to form iodine (I₂), hydroxide (OH^-), and oxygen (O₂). Balance the following reaction equation and report the sum of the stoichiometric coefficients. O₃ I^- H₂O I₂ OH^- O₂

One mole is defined as ________

Combustion analysis of an organic compound to determine the percentages of carbon, hydrogen, and oxygen in the compound depends on which of the following assumptions?

How many oxygen atoms are there in 27.0 g of sodium sulfate (Na₂SO₄)?

Elemental analysis of the organic compound meta-xylene shows that it is 9.49% H and 90.51% C by mass. What is the empirical formula of this hydrocarbon?

Which statement A-D regarding the terms mole and molar mass is not correct?

Air bags in cars inflate when an electrical spark activates sodium azide (NaN₃) so that it decomposes to sodium metal, Na, and nitrogen gas, N₂. In the balanced reaction equation, how many moles of nitrogen gas are formed for each mole of sodium azide?

What is the difference in the chemistry between photosynthesis and respiration?

How many moles of ammonia are there in a 346 g sample of pure NH₃ (17.03 g/mol)?

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

Exam 3: Stoichiometry: Mass, Formulas, and Reactions

How many chlorine atoms are there in 16.0 g of carbon tetrachloride (CCl4)?

A tiny speck (8.3 10-7 mol) of radioactive americium-241 is used in smoke detectors. How many atoms of americium-241 are there in one of these smoke detectors?

Write a definition of the phrase "stoichiometry of a chemical reaction."

Which substance listed below contains the most oxygen atoms?

What is the formula mass of (NH4)3PO4 (ammonium phosphate)?

Which molecules shown below have the same empirical formula?

One form of asbestos called chrysotile is considered to be a human carcinogen. Mass analysis shows that the composition of chrysotile is 26.3% Mg, 20.2% Si, 1.45% H, and the remainder of the mass is oxygen. Determine the empirical formula of chrysotile.

Carbon monoxide is used in refining iron ore to produce the metal. Assuming the reaction yield is 100%, how many grams of iron would be produced if 5.00 mol of carbon monoxide were exposed to 800 g iron(III) oxide? Fe2O3(s) 3CO(g) 2Fe(s) 3CO2(g)

Chlorhexidine is an antibacterial drug found in mouthwash and has an elemental analysis of 52.28% carbon, 5.98% hydrogen, 14.03% chlorine, and 27.71% nitrogen. It has a molar mass of 505.45 g/mol. What is the molecular formula of chlorhexidine?

Ozone (O3) reacts with iodide (I-) and water to form iodine (I2), hydroxide (OH-), and oxygen (O2). Balance the following reaction equation and report the sum of the stoichiometric coefficients. O3 I- H2O I2 OH- O2

One mole is defined as ________

Combustion analysis of an organic compound to determine the percentages of carbon, hydrogen, and oxygen in the compound depends on which of the following assumptions?

How many oxygen atoms are there in 27.0 g of sodium sulfate (Na2SO4)?

Elemental analysis of the organic compound meta-xylene shows that it is 9.49% H and 90.51% C by mass. What is the empirical formula of this hydrocarbon?

Which statement A-D regarding the terms mole and molar mass is not correct?

Air bags in cars inflate when an electrical spark activates sodium azide (NaN3) so that it decomposes to sodium metal, Na, and nitrogen gas, N2. In the balanced reaction equation, how many moles of nitrogen gas are formed for each mole of sodium azide?

What is the difference in the chemistry between photosynthesis and respiration?

How many moles of ammonia are there in a 346 g sample of pure NH3 (17.03 g/mol)?

Matter and Energy: The Origin of the Universe

Atoms, Ions, and Molecules: Matter Starts Here

Solution Chemistry: The Hydrosphere

Thermochemistry: Energy Changes in Reactions

Properties of Gases: The Air We Breathe

A Quantum Model of Atoms: Waves and Particles

Chemical Bonds: What Makes a Gas a Greenhouse Gas

Molecular Geometry: Shape Determines Function

Intermolecular Forces: The Uniqueness of Water

Solutions: Properties and Behavior

Solids: Crystals, Alloys, and Polymers

Chemical Kinetics: Reactions in the Atmosphere

Chemical Equilibrium: How Much Product Does a Reaction Really Make

Acidbase Equilibria: Proton Transfer in Biological Systems

Additional Aqueous Equilibria: Chemistry and the Oceans

Thermodynamics: Spontaneous and Nonspontaneous Reactions and Processes

Electrochemistry: The Quest for Clean Energy

Nuclear Chemistry: Applications to Energy and Medicine

Organic and Biological Molecules: the Compounds of Life

The Main Group Elements: Life and the Periodic Table

Transition Metals: Biological and Medical Applications

Filters

How many chlorine atoms are there in 16.0 g of carbon tetrachloride (CCl₄)?

A tiny speck (8.3 10^-7 mol) of radioactive americium-241 is used in smoke detectors. How many atoms of americium-241 are there in one of these smoke detectors?

What is the formula mass of (NH₄)₃PO₄ (ammonium phosphate)?

Carbon monoxide is used in refining iron ore to produce the metal. Assuming the reaction yield is 100%, how many grams of iron would be produced if 5.00 mol of carbon monoxide were exposed to 800 g iron(III) oxide? Fe₂O₃(s) 3CO(g) 2Fe(s) 3CO₂(g)

Ozone (O₃) reacts with iodide (I^-) and water to form iodine (I₂), hydroxide (OH^-), and oxygen (O₂). Balance the following reaction equation and report the sum of the stoichiometric coefficients. O₃ I^- H₂O I₂ OH^- O₂

How many oxygen atoms are there in 27.0 g of sodium sulfate (Na₂SO₄)?

Air bags in cars inflate when an electrical spark activates sodium azide (NaN₃) so that it decomposes to sodium metal, Na, and nitrogen gas, N₂. In the balanced reaction equation, how many moles of nitrogen gas are formed for each mole of sodium azide?

How many moles of ammonia are there in a 346 g sample of pure NH₃ (17.03 g/mol)?