Question 1

A friend argues that if mass were really conserved he would never need to refill his gas tank.What explanation do you offer your friend?

Accepted Answer

A) The atoms (mass)of gasoline are converted into energy by the engine according to E=m $c ^ { 2 }$ . 
B) The Law of Conservation of Mass does not apply to reactions involving combustion or explosion of matter. 
C) The atoms (mass)of gasoline are converted into exhaust fumes. 
D) The oil companies make gasoline in a way that it gets used up so that we are always required to replenish it. 
A) The atoms (mass)of gasoline are converted into energy by the engine according to E=m $c ^ { 2 }$ . 
B) The Law of Conservation of Mass does not apply to reactions involving combustion or explosion of matter. 
C) The atoms (mass)of gasoline are converted into exhaust fumes. 
D) The oil companies make gasoline in a way that it gets used up so that we are always required to replenish it.

Question 2

Which of the following reaction energies is the most endothermic?

Accepted Answer

A) 540 kJ/mole 
B) -540 kJ/mole 
C) 125 kj/mole 
D) -125 kJ/mole 
E) not enough information given 
A) 540 kJ/mole 
B) -540 kJ/mole 
C) 125 kj/mole 
D) -125 kJ/mole 
E) not enough information given

Question 3

What is the activation energy?

Accepted Answer

A) the minimum amount of energy to break the bonds in reactants 
B) the amount of energy required to activate a phase change 
C) the energy difference between the reactants and the products 
D) the amount of energy required to separate reactants from the products 
E) the hill 
A) the minimum amount of energy to break the bonds in reactants 
B) the amount of energy required to activate a phase change 
C) the energy difference between the reactants and the products 
D) the amount of energy required to separate reactants from the products 
E) the hill

Question 4

What is a chemical equation?

Accepted Answer

A) It is a shorthand notation for illustrating a chemical reaction. 
B) It is the sum of the masses of the products and reactants. 
C) It is the chemical combination of equal numbers of reactants and products. 
D) It is a picture of the atoms undergoing a chemical equalization. 
E) It is any type of reaction that takes place at the equator. 
A) It is a shorthand notation for illustrating a chemical reaction. 
B) It is the sum of the masses of the products and reactants. 
C) It is the chemical combination of equal numbers of reactants and products. 
D) It is a picture of the atoms undergoing a chemical equalization. 
E) It is any type of reaction that takes place at the equator.

Question 5

Given the following generic chemical reaction,which is the reactant? X → Y

Accepted Answer

A) Y is the reactant. 
B) X is the reactant. 
C) → is the reactant. 
D) Both X and Y are the products. 
E) Both X and Y are the reactants. 
A) Y is the reactant. 
B) X is the reactant. 
C) → is the reactant. 
D) Both X and Y are the products. 
E) Both X and Y are the reactants.

Question 6

Is it possible to have a macroscopic sample of oxygen that has a mass of 14 atomic mass units?

Accepted Answer

A) Yes,but it would need to be made of oxygen atoms that each had less than the normal number of neutrons. 
B) No,this is less than than the mass of a single oxygen atom. 
C) Yes,but it would have the same density as nitrogen. 
D) No,because oxygen is a gas at room temperature. 
A) Yes,but it would need to be made of oxygen atoms that each had less than the normal number of neutrons. 
B) No,this is less than than the mass of a single oxygen atom. 
C) Yes,but it would have the same density as nitrogen. 
D) No,because oxygen is a gas at room temperature.

Question 7

What is the mass of a water molecule, $\mathrm { H } _ { 2 }$ O,in atomic mass units?

Accepted Answer

A) 2 amu 
B) 3 amu 
C) 16 amu 
D) 18 amu 
A) 2 amu 
B) 3 amu 
C) 16 amu 
D) 18 amu

Question 8

If it takes three golf balls to equal the mass of one tennis ball,what mass of tennis balls do you need to equal the number of golf balls in one kilogram of golf balls?

Accepted Answer

A) 1/3 of a kg 
B) 30 kg 
C) 1 kg 
D) 3 kg 
E) 6 kg 
A) 1/3 of a kg 
B) 30 kg 
C) 1 kg 
D) 3 kg 
E) 6 kg

Question 9

A catalytic converter increases the amount of carbon dioxide emitted by an automobile.Is this good news or bad news?

Accepted Answer

A) bad news because carbon dioxide contributes to global warming 
B) good news because plants thrive on carbon dioxide 
C) bad news because the carbon dioxide contributes to acid rain 
D) good news because it means more noxious chemicals are not being emitted 
A) bad news because carbon dioxide contributes to global warming 
B) good news because plants thrive on carbon dioxide 
C) bad news because the carbon dioxide contributes to acid rain 
D) good news because it means more noxious chemicals are not being emitted

Question 10

How many bonds between nitrogen and hydrogen are formed if you react nitrogen with hydrogen according to the following reaction? N2 + 3H2 → 2 NH3

Accepted Answer

A) 6 
B) 2 
C) 3 
D) 1 
E) 8 
A) 6 
B) 2 
C) 3 
D) 1 
E) 8

Question 11

If it takes three carbon atoms to equal the mass of one chlorine atom,what weight of chlorine do you need to equal the number of atoms in one kilogram of carbon?

Accepted Answer

A) 1/3 of a kg 
B) 30 kg 
C) 1 kg 
D) 3 kg 
E) 6 kg 
A) 1/3 of a kg 
B) 30 kg 
C) 1 kg 
D) 3 kg 
E) 6 kg

Question 12

Which of the following is a correctly balanced equation?

Accepted Answer

A) P4 + 6 H2 → 4 PH3 
B) 1 P4 + 6 H2 → 4 PH3 
C) 0 P4 + 6 H2 → 4 PH3 
D) 2 P4 + 12 H2 → 8 PH3 
E) P4 + 3 H2 → PH3 
A) P4 + 6 H2 → 4 PH3 
B) 1 P4 + 6 H2 → 4 PH3 
C) 0 P4 + 6 H2 → 4 PH3 
D) 2 P4 + 12 H2 → 8 PH3 
E) P4 + 3 H2 → PH3

Question 13

A refrigerator delays the spoilage of food by

Accepted Answer

A) killing microorganisms. 
B) slowing down the rate of chemical reactions within microorganisms. 
C) expanding the water found within microorganisms. 
D) diminishing the supply of oxygen to microorganisms. 
A) killing microorganisms. 
B) slowing down the rate of chemical reactions within microorganisms. 
C) expanding the water found within microorganisms. 
D) diminishing the supply of oxygen to microorganisms.

Question 14

Is the synthesis of ozone, $\mathrm { O } _ { 3 }$ ,from oxygen, $\mathrm { O } _ { 2 }$ ,an example of an exothermic or endothermic reaction?

Accepted Answer

A) exothermic because ultraviolet light is emitted during its formation 
B) endothermic because ultraviolet light is emitted during its formation 
C) exothermic because ultraviolet light is absorbed during its formation 
D) endothermic because ultraviolet light is absorbed during its formation 
A) exothermic because ultraviolet light is emitted during its formation 
B) endothermic because ultraviolet light is emitted during its formation 
C) exothermic because ultraviolet light is absorbed during its formation 
D) endothermic because ultraviolet light is absorbed during its formation

Question 15

Many people hear about atmospheric ozone depletion and wonder why we don't simply replace that which has been destroyed.Knowing about CFCs and how catalysts work,explain how this would not be a lasting solution.

Accepted Answer

A) The amount of energy required to create and transport sufficient ozone to the stratosphere would be cost prohibitive. 
B) Governments would be too slow to respond as they argued about who should shoulder the burden of undertaking such an endeavor. 
C) Any ozone we placed into the stratosphere would be destroyed by the same catalytic action that destroys naturally occurring stratospheric ozone. 
D) all of the above 
A) The amount of energy required to create and transport sufficient ozone to the stratosphere would be cost prohibitive. 
B) Governments would be too slow to respond as they argued about who should shoulder the burden of undertaking such an endeavor. 
C) Any ozone we placed into the stratosphere would be destroyed by the same catalytic action that destroys naturally occurring stratospheric ozone. 
D) all of the above

Question 16

What is wrong with the following depiction of a chemical reaction?

Accepted Answer

A) These boxes contain only molecules but no atoms. 
B) One box contains more molecules than the other. 
C) One box contains more atoms than the other. 
D) All of the above. 
A) These boxes contain only molecules but no atoms. 
B) One box contains more molecules than the other. 
C) One box contains more atoms than the other. 
D) All of the above.

Question 17

How many oxygen molecules are needed to make 10 carbon dioxide molecules according to the following balanced chemical equation? 2 CO + O2 → 2 CO2

Accepted Answer

A) 5 
B) 1 
C) 4 
D) 10 
E) 2 
A) 5 
B) 1 
C) 4 
D) 10 
E) 2

Question 18

Which of the following statements best describes the concept of entropy?

Accepted Answer

A) Energy has a tendency to disperse. 
B) Energy is neither created nor destroyed. 
C) The entropy of the universe is constantly decreasing. 
D) The energy released in a chemical reaction is the same as the difference in the energy of the bonds broken and formed. 
E) Energy has a tendency to remain in one place. 
A) Energy has a tendency to disperse. 
B) Energy is neither created nor destroyed. 
C) The entropy of the universe is constantly decreasing. 
D) The energy released in a chemical reaction is the same as the difference in the energy of the bonds broken and formed. 
E) Energy has a tendency to remain in one place.

Question 19

Steel wool wetted with vinegar is stuffed into a narrow mouth round glass bottle.A rubber balloon is then sealed over the mouth of the bottle.After several hours,the balloon inflates into the bottle in an inverted manner.What happened?

Accepted Answer

A) Vinegar fumes are diamagnetic and as they accumulate above the liquid the steel wool is attracted thus inflating the balloon into the mouth of the bottle in an inverted manner. 
B) The caustic vinegar fumes get past the steel wool and deteriorate the balloon,which begins to sag into the bottle and inflate it in an inverted manner. 
C) The vinegar reacts with the steel wool by absorbing oxygen within the bottle thus decreasing the pressure.The greater outside pressure causes the balloon to inflate in an inverted manner. 
D) False! The balloon inflates above the mouth of the bottle because the reaction between the vinegar and steel wool produces a gas which is forced upward because of increased pressure inside the sealed bottle. 
A) Vinegar fumes are diamagnetic and as they accumulate above the liquid the steel wool is attracted thus inflating the balloon into the mouth of the bottle in an inverted manner. 
B) The caustic vinegar fumes get past the steel wool and deteriorate the balloon,which begins to sag into the bottle and inflate it in an inverted manner. 
C) The vinegar reacts with the steel wool by absorbing oxygen within the bottle thus decreasing the pressure.The greater outside pressure causes the balloon to inflate in an inverted manner. 
D) False! The balloon inflates above the mouth of the bottle because the reaction between the vinegar and steel wool produces a gas which is forced upward because of increased pressure inside the sealed bottle.

Question 20

According to the following balanced chemical equation,if you want to generate two moles of H2O,how many moles of O2 do you need? 2 H2 + O2 → 2 H2O

Accepted Answer

A) 1 
B) 2 
C) 1/2 
D) 4 
E) 6.022 × 1023 
A) 1 
B) 2 
C) 1/2 
D) 4 
E) 6.022 × 1023

Exam 17: How Chemicals React

A friend argues that if mass were really conserved he would never need to refill his gas tank.What explanation do you offer your friend?

Which of the following reaction energies is the most endothermic?

What is the activation energy?

What is a chemical equation?

Given the following generic chemical reaction,which is the reactant? X → Y

Is it possible to have a macroscopic sample of oxygen that has a mass of 14 atomic mass units?

What is the mass of a water molecule, H2\mathrm { H } _ { 2 }H2​ O,in atomic mass units?

If it takes three golf balls to equal the mass of one tennis ball,what mass of tennis balls do you need to equal the number of golf balls in one kilogram of golf balls?

A catalytic converter increases the amount of carbon dioxide emitted by an automobile.Is this good news or bad news?

How many bonds between nitrogen and hydrogen are formed if you react nitrogen with hydrogen according to the following reaction? N2 + 3H2 → 2 NH3

If it takes three carbon atoms to equal the mass of one chlorine atom,what weight of chlorine do you need to equal the number of atoms in one kilogram of carbon?

Which of the following is a correctly balanced equation?

A refrigerator delays the spoilage of food by

Is the synthesis of ozone, O3\mathrm { O } _ { 3 }O3​ ,from oxygen, O2\mathrm { O } _ { 2 }O2​ ,an example of an exothermic or endothermic reaction?

Many people hear about atmospheric ozone depletion and wonder why we don't simply replace that which has been destroyed.Knowing about CFCs and how catalysts work,explain how this would not be a lasting solution.

What is wrong with the following depiction of a chemical reaction?

How many oxygen molecules are needed to make 10 carbon dioxide molecules according to the following balanced chemical equation? 2 CO + O2 → 2 CO2

Which of the following statements best describes the concept of entropy?

Steel wool wetted with vinegar is stuffed into a narrow mouth round glass bottle.A rubber balloon is then sealed over the mouth of the bottle.After several hours,the balloon inflates into the bottle in an inverted manner.What happened?

According to the following balanced chemical equation,if you want to generate two moles of H2O,how many moles of O2 do you need? 2 H2 + O2 → 2 H2O

Patterns of Motion and Equilibrium

Newtons Laws of Motion

Momentum and Energy

Gravity, Projectiles, and Satellites

Fluid Mechanics

Thermal Energy and Thermodynamics

Heat Transfer and Change of Phase

Static and Current Electricity

Magnetism and Electromagnetic Induction

Waves and Sound

Light

Atoms and the Periodic Table

The Atomic Nucleus and Radioactivity

Elements of Chemistry

How Atoms Bond and Molecules Attract

Mixtures

Two Classes of Chemical Reactions

Organic Compounds

Rocks and Minerals

Plate Tectonics and Earths Interior

Shaping Earths Surface

Geologic Time - Reading the Rock Record

The Oceans, Atmosphere, and Climatic Effects

Driving Forces of Weather

The Solar System

Stars and Galaxies

The Structure of Space and Time

Prologue: The Nature of Science

Filters

What is the mass of a water molecule, $\mathrm { H } _ { 2 }$ O,in atomic mass units?

How many bonds between nitrogen and hydrogen are formed if you react nitrogen with hydrogen according to the following reaction? N₂ + 3H₂ → 2 NH₃

Is the synthesis of ozone, $\mathrm { O } _ { 3 }$ ,from oxygen, $\mathrm { O } _ { 2 }$ ,an example of an exothermic or endothermic reaction?

How many oxygen molecules are needed to make 10 carbon dioxide molecules according to the following balanced chemical equation? 2 CO + O₂ → 2 CO₂

According to the following balanced chemical equation,if you want to generate two moles of H₂O,how many moles of O₂ do you need? 2 H₂ + O₂ → 2 H₂O