Question 1

-For the above energy profiles,which reaction has the highest activation energy?

Accepted Answer

A) a 
B) b 
C) c 
D) d 
E) All have the same activation energy. 
A) a 
B) b 
C) c 
D) d 
E) All have the same activation energy.

Question 2

How many grams of water can be formed from the reaction between 10 grams of oxygen and 1 gram of hydrogen?

Accepted Answer

A) 11 grams of water are formed since mass must be conserved. 
B) 10 grams of water are formed since you can't get a greater mass of water produced than oxygen reacting. 
C) 9 grams of water are formed because oxygen and hydrogen react in an 8:1 ratio. 
D) No water is formed because there is insufficient hydrogen to react with the oxygen. 
A) 11 grams of water are formed since mass must be conserved. 
B) 10 grams of water are formed since you can't get a greater mass of water produced than oxygen reacting. 
C) 9 grams of water are formed because oxygen and hydrogen react in an 8:1 ratio. 
D) No water is formed because there is insufficient hydrogen to react with the oxygen.

Question 3

What is the mass of an oxygen atom,O,in atomic mass units?

Accepted Answer

A) 12 amu 
B) 16 amu 
C) 18 amu 
D) 32 amu 
A) 12 amu 
B) 16 amu 
C) 18 amu 
D) 32 amu

Question 4

If it takes 20 beryllium atoms to equal the mass of two krypton atoms,what is the relative mass of beryllium compared to krypton?

Accepted Answer

A) 1/10 
B) 1/20 
C) 40 times 
D) 100 times 
E) 10 times 
A) 1/10 
B) 1/20 
C) 40 times 
D) 100 times 
E) 10 times

Question 5

How much energy,in kilojoules,is released or absorbed from the reaction of one mole of nitrogen, $\mathrm { N } _ { 2 }$ ,with three moles of molecular hydrogen, $\mathrm { H } _ { 2 }$ ,to form two moles of ammonia,N $\mathrm { H } _ { 3 }$ ? H-N (bond energy: 389 kJ/mol)
H-H (bond energy: 436 kJ/mol)
N   N (bond energy: 946 kJ/mol)
N   N + H-H + H-H ? N $\mathrm { H } _ { 3 }$ + N $\mathrm { H } _ { 3 }$

Accepted Answer

A) +899 kJ/mol absorbed 
B) -993 kJ/mol released 
C) +80 kJ/mol absorbed 
D) -80 kj/mol released 
A) +899 kJ/mol absorbed 
B) -993 kJ/mol released 
C) +80 kJ/mol absorbed 
D) -80 kj/mol released

Question 6

Which is greater: 1.01 amu of hydrogen or 1.01 grams of hydrogen?

Accepted Answer

A) 1.01 amu of hydrogen is greater than 1.01 grams of hydrogen. 
B) 1.01 grams of hydrogen is greater than 1.01 amu of hydrogen. 
C) 1.01 grams of hydrogen and 1.01 amu of hydrogen have the same mass. 
D) Not enough information information is provided. 
A) 1.01 amu of hydrogen is greater than 1.01 grams of hydrogen. 
B) 1.01 grams of hydrogen is greater than 1.01 amu of hydrogen. 
C) 1.01 grams of hydrogen and 1.01 amu of hydrogen have the same mass. 
D) Not enough information information is provided.

Question 7

Bond energies increase in going from C-N (lowest)to C-O to C-F (highest).Explain this trend based upon the atomic sizes of these atoms as deduced from their positions in the periodic table.

Accepted Answer

A) In going from nitrogen to oxygen to fluorine the atoms get larger.This means a greater nuclear charge,which translates into stronger chemical bonds. 
B) In going from nitrogen to oxygen to fluorine the atoms get smaller.This means a greater nuclear charge,which translates into stronger chemical bonds. 
C) In going from nitrogen to oxygen to fluorine the atoms get larger.This means that the bonding atoms are farther apart,which translates into a greater bond energy. 
D) In going from nitrogen to oxygen to fluorine the atoms get smaller.This means that the bonding atoms are closer together,which translates into a greater bond energy. 
A) In going from nitrogen to oxygen to fluorine the atoms get larger.This means a greater nuclear charge,which translates into stronger chemical bonds. 
B) In going from nitrogen to oxygen to fluorine the atoms get smaller.This means a greater nuclear charge,which translates into stronger chemical bonds. 
C) In going from nitrogen to oxygen to fluorine the atoms get larger.This means that the bonding atoms are farther apart,which translates into a greater bond energy. 
D) In going from nitrogen to oxygen to fluorine the atoms get smaller.This means that the bonding atoms are closer together,which translates into a greater bond energy.

Question 8

How many molecules of aspirin (formula mass aspirin = 180.0 amu)are there in a 0.250-gram sample?

Accepted Answer

A) 6.02 × $10 ^ { 23 }$ 
B) 8.36 × $10 ^ { 20 }$ 
C) 1.51 × $10 ^ { 23 }$ 
D) More information is needed. 
A) 6.02 × $10 ^ { 23 }$ 
B) 8.36 × $10 ^ { 20 }$ 
C) 1.51 × $10 ^ { 23 }$ 
D) More information is needed.

Question 9

An Alka-Seltzer antacid tablet bubbles vigorously when placed in water but only slowly when placed in an alcoholic beverage of the same temperature containing a 50:50 mix of alcohol and water.Propose a probable explanation involving the relationship between the speed of a reaction and molecular collisions.

Accepted Answer

A) The alcohol absorbs the carbon dioxide bubbles before they escape the liquid phase. 
B) Alcohol molecules are more massive than water molecules,hence they move slower and their collisions are not as forceful. 
C) The tablet reacts with water but not the alcohol. 
D) In a 50:50 mix there are fewer water molecules for the antacid molecules to collide with. 
A) The alcohol absorbs the carbon dioxide bubbles before they escape the liquid phase. 
B) Alcohol molecules are more massive than water molecules,hence they move slower and their collisions are not as forceful. 
C) The tablet reacts with water but not the alcohol. 
D) In a 50:50 mix there are fewer water molecules for the antacid molecules to collide with.

Question 10

Small samples of oxygen gas needed in the laboratory can be generated by any number of simple chemical reactions,such as 2 KCl $\mathrm { O } _ { 3 }$ (s)? 2 KCl (s)+ 3 $\mathrm { O } _ { 2 }$ (g)
What mass of oxygen (in grams)is produced when 122.6 g of KCl $\mathrm { O } _ { 3 }$ (formula mass = 122.6 amu)takes part in this reaction?

Accepted Answer

A) 32.00 grams 
B) 48.00 grams 
C) 96.00 grams 
D) More information is needed. 
A) 32.00 grams 
B) 48.00 grams 
C) 96.00 grams 
D) More information is needed.

Question 11

The concept of entropy tells us how exothermic reactions are

Accepted Answer

A) favored over endothermic reactions. 
B) not as favorable as endothermic reactions. 
C) just as effective as endothermic reactions. 
D) the reverse of endothermic reactions. 
A) favored over endothermic reactions. 
B) not as favorable as endothermic reactions. 
C) just as effective as endothermic reactions. 
D) the reverse of endothermic reactions.

Question 12

-For the above energy profiles,which reaction has the lowest activation energy?

Accepted Answer

A) a 
B) b 
C) c 
D) d 
E) All have the same activation energy. 
A) a 
B) b 
C) c 
D) d 
E) All have the same activation energy.

Question 13

Which of the following reaction energies is the least exothermic (but still an exothermic reaction)?

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 14

For the following balanced equation,which has the highest coefficient? 4 H2 + 2 C → 2 CH4

Accepted Answer

A) H2 
B) C 
C) CH4 
D) H4 
E) none of the above 
A) H2 
B) C 
C) CH4 
D) H4 
E) none of the above

Question 15

A 1.00 carat pure diamond has a mass of 0.20 grams.How many carbon atoms are there within this diamond?

Accepted Answer

A) 6.0 × $10 ^ { 23 }$ carbon atoms 
B) 2.0 × $10 ^ { 22 }$ carbon atoms 
C) 1.0 × $10 ^ { 22 }$ carbon atoms 
D) 6.0 × $10 ^ { 22 }$ 
A) 6.0 × $10 ^ { 23 }$ carbon atoms 
B) 2.0 × $10 ^ { 22 }$ carbon atoms 
C) 1.0 × $10 ^ { 22 }$ carbon atoms 
D) 6.0 × $10 ^ { 22 }$

Question 16

Why do the natural reactions involving ozone not lead to depletion of the ozone layer?

Accepted Answer

A) Ozone continually rises from the troposphere. 
B) Ozone is too diffuse. 
C) Ozone breaks into fragments that can reassemble into more ozone. 
D) UV radiation generates more ozone. 
E) c and d 
A) Ozone continually rises from the troposphere. 
B) Ozone is too diffuse. 
C) Ozone breaks into fragments that can reassemble into more ozone. 
D) UV radiation generates more ozone. 
E) c and d

Question 17

Which has the greatest number of atoms?

Accepted Answer

A) 28 g of nitrogen, $\mathrm { N } _ { 2 }$ 
B) 32 g of oxygen, $\mathrm { O } _ { 2 }$ 
C) 16 g of methane,C $\mathrm { H } _ { 4 }$ 
D) 38 g of fluorine, $\mathrm { F } _ { 2 }$ 
A) 28 g of nitrogen, $\mathrm { N } _ { 2 }$ 
B) 32 g of oxygen, $\mathrm { O } _ { 2 }$ 
C) 16 g of methane,C $\mathrm { H } _ { 4 }$ 
D) 38 g of fluorine, $\mathrm { F } _ { 2 }$

Question 18

What is the formula mass of a molecule of CO2?

Accepted Answer

A) 44 amu 
B) 56 amu 
C) 58.9 amu 
D) 118 amu 
E) none of the above 
A) 44 amu 
B) 56 amu 
C) 58.9 amu 
D) 118 amu 
E) none of the above

Question 19

Which of the following statements accurately describes the action of ozone?

Accepted Answer

A) It absorbs UV radiation and undergoes fragmentation. 
B) It reflects UV radiation back into space. 
C) It reflects heat back into space. 
D) It emits UV radiation when excited by sunlight. 
E) none of the above 
A) It absorbs UV radiation and undergoes fragmentation. 
B) It reflects UV radiation back into space. 
C) It reflects heat back into space. 
D) It emits UV radiation when excited by sunlight. 
E) none of the above

Question 20

The yeast in bread dough feeds on sugar to produce carbon dioxide.Why does the dough rise faster in a warmer area?

Accepted Answer

A) There is a greater number of effective collisions among reacting molecules. 
B) Atmospheric pressure decreases with increasing temperature. 
C) The yeast tends to "wake up" with warmer temperatures,which is why baker's yeast is best stored in the refrigerator. 
D) The rate of evaporation increases with increasing temperature. 
A) There is a greater number of effective collisions among reacting molecules. 
B) Atmospheric pressure decreases with increasing temperature. 
C) The yeast tends to "wake up" with warmer temperatures,which is why baker's yeast is best stored in the refrigerator. 
D) The rate of evaporation increases with increasing temperature.

Exam 17: How Chemicals React

-For the above energy profiles,which reaction has the highest activation energy?

How many grams of water can be formed from the reaction between 10 grams of oxygen and 1 gram of hydrogen?

What is the mass of an oxygen atom,O,in atomic mass units?

If it takes 20 beryllium atoms to equal the mass of two krypton atoms,what is the relative mass of beryllium compared to krypton?

Which is greater: 1.01 amu of hydrogen or 1.01 grams of hydrogen?

Bond energies increase in going from C-N (lowest)to C-O to C-F (highest).Explain this trend based upon the atomic sizes of these atoms as deduced from their positions in the periodic table.

How many molecules of aspirin (formula mass aspirin = 180.0 amu)are there in a 0.250-gram sample?

The concept of entropy tells us how exothermic reactions are

-For the above energy profiles,which reaction has the lowest activation energy?

Which of the following reaction energies is the least exothermic (but still an exothermic reaction)?

For the following balanced equation,which has the highest coefficient? 4 H2 + 2 C → 2 CH4

A 1.00 carat pure diamond has a mass of 0.20 grams.How many carbon atoms are there within this diamond?

Why do the natural reactions involving ozone not lead to depletion of the ozone layer?

Which has the greatest number of atoms?

What is the formula mass of a molecule of CO2?

Which of the following statements accurately describes the action of ozone?

The yeast in bread dough feeds on sugar to produce carbon dioxide.Why does the dough rise faster in a warmer area?

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

For the following balanced equation,which has the highest coefficient? 4 H₂ + 2 C → 2 CH₄

What is the formula mass of a molecule of CO₂?