Question 1

Why do ice cubes get smaller when left in the freezer for a long time?

Accepted Answer

A) The ice cubes melt during the brief warming cycles of auto-defrost and freezer access, thus leaving the ice cubes smaller and making them stick together in clumps. 
B) The water molecules of the ice sublime from the solid to gaseous phase without ever entering a liquid phase. 
C) Both A and B occur. 
D) Neither A nor B accurately explain why ice cubes get smaller in the freezer over time. 
A) The ice cubes melt during the brief warming cycles of auto-defrost and freezer access, thus leaving the ice cubes smaller and making them stick together in clumps. 
B) The water molecules of the ice sublime from the solid to gaseous phase without ever entering a liquid phase. 
C) Both A and B occur. 
D) Neither A nor B accurately explain why ice cubes get smaller in the freezer over time.

Question 2

Water will boil spontaneously in a vacuum. Could you cook an egg in this boiling water?

Accepted Answer

A) Yes, since the water is boiling it has enough energy to cook the egg even if it is at room temperature. 
B) No, because food is cooked by the transfer of thermal energy from the water to the food, and water at room temperature does not have enough thermal energy to cook an egg. 
C) Yes, since the food is not under pressure in the vacuum, it will also cook at a much lower temperature. 
D) No, the food would not cook because the thermal energy could not be transferred to the food in a vacuum. 
A) Yes, since the water is boiling it has enough energy to cook the egg even if it is at room temperature. 
B) No, because food is cooked by the transfer of thermal energy from the water to the food, and water at room temperature does not have enough thermal energy to cook an egg. 
C) Yes, since the food is not under pressure in the vacuum, it will also cook at a much lower temperature. 
D) No, the food would not cook because the thermal energy could not be transferred to the food in a vacuum.

Question 3

Suppose that water is used in a thermometer instead of mercury. If the temperature is at 4°C and then changes, why can't the thermometer indicate whether the temperature is rising or falling?

Accepted Answer

A) The water molecules will be a mixture of ice and water, and a change in temperature will only change the proportions of its phases. 
B) The water molecules are moving too slowly to be able to indicate a change. 
C) Water is most dense at 4°C. The water in a water-filled thermometer at 4°C would expand as the water was cooled or heated. 
D) Since water has such a high specific heat capacity, it will take a lot of energy to be able to see a change in the thermometer. 
A) The water molecules will be a mixture of ice and water, and a change in temperature will only change the proportions of its phases. 
B) The water molecules are moving too slowly to be able to indicate a change. 
C) Water is most dense at 4°C. The water in a water-filled thermometer at 4°C would expand as the water was cooled or heated. 
D) Since water has such a high specific heat capacity, it will take a lot of energy to be able to see a change in the thermometer.

Question 4

Like water, hydrogen fluoride, HF, and ammonia, N   , have relatively high boiling points. Explain.

Accepted Answer

A) Even though HF and N   have ionic bonds, like water they have a strong attraction for themselves. 
B) Since these are all relatively small molecules, they can compact more tightly together, and will require more energy to be separated from each other. 
C) The polar molecules of each of these materials have relatively strong attractions for themselves, which translates to relatively high boiling points. 
D) Since these molecules interact with each other in long chains, they have many regions of attraction and are held together relatively tightly, thus, they are harder to pull apart when boiling. 
A) Even though HF and N   have ionic bonds, like water they have a strong attraction for themselves. 
B) Since these are all relatively small molecules, they can compact more tightly together, and will require more energy to be separated from each other. 
C) The polar molecules of each of these materials have relatively strong attractions for themselves, which translates to relatively high boiling points. 
D) Since these molecules interact with each other in long chains, they have many regions of attraction and are held together relatively tightly, thus, they are harder to pull apart when boiling.

Question 5

How are pressure and the boiling point of a compound related?

Accepted Answer

A) As the pressure decreases the boiling point decreases. 
B) As the boiling point increases the pressure decreases. 
C) As the pressure decreases the boiling point increases. 
D) As the boiling point decreases the pressure increases. 
E) none of the above 
A) As the pressure decreases the boiling point decreases. 
B) As the boiling point increases the pressure decreases. 
C) As the pressure decreases the boiling point increases. 
D) As the boiling point decreases the pressure increases. 
E) none of the above

Question 6

What would happen to the oceans if the atmosphere suddenly disappeared?

Accepted Answer

A) There would be little or no change. Oceans are known to exist on other planets without atmospheres. 
B) The oceans would completely evaporate filling the void left by the atmosphere with water vapor and leaving behind billions of tons of salt deposit. 
C) The missing air would be replaced by water vapor as the upper layers of the ocean began to boil. 
D) The oceans would freeze to a solid ice mass since the temperature of the earth would drop below   . 
A) There would be little or no change. Oceans are known to exist on other planets without atmospheres. 
B) The oceans would completely evaporate filling the void left by the atmosphere with water vapor and leaving behind billions of tons of salt deposit. 
C) The missing air would be replaced by water vapor as the upper layers of the ocean began to boil. 
D) The oceans would freeze to a solid ice mass since the temperature of the earth would drop below   .

Question 7

Which of the following statements describes what happens when a given mass of a liquid starts to expand?

Accepted Answer

A) Its density decreases. 
B) Its density increases. 
C) Its density does not change. 
D) Its mass increases. 
E) Its volume decreases. 
A) Its density decreases. 
B) Its density increases. 
C) Its density does not change. 
D) Its mass increases. 
E) Its volume decreases.

Question 8

Why are drops of water shaped like spheres?

Accepted Answer

A) Water molecules at the surface are pulled into the liquid, making the drop as small as possible. 
B) The interatomic forces are strongest for spherical shapes and so the molecules arrange into spheres. 
C) Water molecules are composed of spheres and so the bulk material takes on the same shape. 
D) Water molecules are special and are the only molecules that form spheres. This is one of water's unique physical properties. 
A) Water molecules at the surface are pulled into the liquid, making the drop as small as possible. 
B) The interatomic forces are strongest for spherical shapes and so the molecules arrange into spheres. 
C) Water molecules are composed of spheres and so the bulk material takes on the same shape. 
D) Water molecules are special and are the only molecules that form spheres. This is one of water's unique physical properties.

Question 9

Why does evaporation cool a liquid?

Accepted Answer

A) The departing gas molecule takes some kinetic energy with it as it leaves the surface. 
B) The overall heat decreases because the air cools. 
C) The average energy of the system increases because of the increased disorder in the new gas molecules. 
D) The gas molecules need to transfer their kinetic energy to the new slower gas molecule. 
E) none of the above 
A) The departing gas molecule takes some kinetic energy with it as it leaves the surface. 
B) The overall heat decreases because the air cools. 
C) The average energy of the system increases because of the increased disorder in the new gas molecules. 
D) The gas molecules need to transfer their kinetic energy to the new slower gas molecule. 
E) none of the above

Question 10

Why is condensation a warming process? What does condensation warm?

Accepted Answer

A) Condensation transfers slower, lower kinetic energy vapor molecules to the liquid state, thus raising the overall temperature of both the gas and liquid molecules in the process. 
B) Condensation transfers the faster, higher kinetic energy vapor molecules to the liquid state, thus imparting the excess energy to the liquid and raising its temperature. 
C) From a kinetic energy standpoint, we refer to condensation as a warming process. However, only the vapor molecules are losing energy and imparting that energy to the liquid, so only the liquid is warmed. 
D) Condensation cools the vapor and warms the liquid phase. Since the process is always defined by the product, condensation is called a warming process. 
A) Condensation transfers slower, lower kinetic energy vapor molecules to the liquid state, thus raising the overall temperature of both the gas and liquid molecules in the process. 
B) Condensation transfers the faster, higher kinetic energy vapor molecules to the liquid state, thus imparting the excess energy to the liquid and raising its temperature. 
C) From a kinetic energy standpoint, we refer to condensation as a warming process. However, only the vapor molecules are losing energy and imparting that energy to the liquid, so only the liquid is warmed. 
D) Condensation cools the vapor and warms the liquid phase. Since the process is always defined by the product, condensation is called a warming process.

Question 11

Which of the following describes what happens when you increase the temperature of water?

Accepted Answer

A) The molecules start to vibrate and move farther apart. 
B) The molecules start to vibrate and move closer together. 
C) The molecular vibrations start to slow and the molecules move farther apart. 
D) The molecular vibrations start to slow and the molecules move closer together. 
E) none of the above. 
A) The molecules start to vibrate and move farther apart. 
B) The molecules start to vibrate and move closer together. 
C) The molecular vibrations start to slow and the molecules move farther apart. 
D) The molecular vibrations start to slow and the molecules move closer together. 
E) none of the above.

Question 12

Given the following specific heats, which would require the greatest amount of heat energy to increase its temperature by 50°C?

Accepted Answer

A) one gram of ammonia, 4.70 J/(g°
C)  
B) Two grams of water, 4.184 J/(g°
C)  
C) Six grams of aluminum, 0.90 J/(g°
C)  
D) Twenty grams of silver, 0.24 J/(g°
C)  
E) All of the above require the same amount of heat energy. 
A) one gram of ammonia, 4.70 J/(g°
C)  
B) Two grams of water, 4.184 J/(g°
C)  
C) Six grams of aluminum, 0.90 J/(g°
C)  
D) Twenty grams of silver, 0.24 J/(g°
C)  
E) All of the above require the same amount of heat energy.

Question 13

What is the gas found within a bubble of boiling water?

Accepted Answer

A) air 
B) chlorine from the water 
C) water vapor 
D) hydrogen 
A) air 
B) chlorine from the water 
C) water vapor 
D) hydrogen

Question 14

The specific heat of a substance is the ________.

Accepted Answer

A) amount of heat required to change the temperature of a given mass 
B) amount of heat energy that is stored in chemical bonds 
C) amount of potential energy in a material that is released when a substance undergoes combustion and gives off heat 
D) temperature at which a compound starts to melt 
E) temperature at which a given mass's heat increases 
A) amount of heat required to change the temperature of a given mass 
B) amount of heat energy that is stored in chemical bonds 
C) amount of potential energy in a material that is released when a substance undergoes combustion and gives off heat 
D) temperature at which a compound starts to melt 
E) temperature at which a given mass's heat increases

Question 15

If it takes 200 J to raise the temperature of a 10-gram block of ice by 10°C, what is the specific heat of the ice?

Accepted Answer

A) 2 J/(g°
C)  
B) 200 J/(g°
C)  
C) 200 J 
D) 10 °C 
E) 20,000 J/(g°
C)  
A) 2 J/(g°
C)  
B) 200 J/(g°
C)  
C) 200 J 
D) 10 °C 
E) 20,000 J/(g°
C)

Question 16

What happens to the freezing temperature of a salt water solution as it becomes more concentrated?

Accepted Answer

A) As salt water becomes more concentrated, the temperature at which it freezes become lower because fewer water molecules of the liquid phase in contact with the ice. 
B) As salt water becomes more concentrated, the temperature at which it freezes become higher because salt ions help to hold together the ice. 
C) As salt water becomes more concentrated, the temperature at which it freezes does not change. 
D) As salt water becomes more concentrated, the temperature at which it freezes become higher because the molecules are moving faster as they interact with the salt ions. 
A) As salt water becomes more concentrated, the temperature at which it freezes become lower because fewer water molecules of the liquid phase in contact with the ice. 
B) As salt water becomes more concentrated, the temperature at which it freezes become higher because salt ions help to hold together the ice. 
C) As salt water becomes more concentrated, the temperature at which it freezes does not change. 
D) As salt water becomes more concentrated, the temperature at which it freezes become higher because the molecules are moving faster as they interact with the salt ions.

Question 17

Evaporation is ________.

Accepted Answer

A) always a cooling process 
B) sometimes a cooling process 
C) always a warming process 
D) sometimes a warming process 
E) Two of the above are correct. 
A) always a cooling process 
B) sometimes a cooling process 
C) always a warming process 
D) sometimes a warming process 
E) Two of the above are correct.

Question 18

Why does water have a high specific heat?

Accepted Answer

A) Much of the added energy is required to break hydrogen bonds. 
B) Water is not very dense like metals and therefore doesn't conduct heat as readily. 
C) Much of the heat that is added to water is converted to kinetic energy. 
D) None of the energy is stored as potential energy. 
E) none of the above 
A) Much of the added energy is required to break hydrogen bonds. 
B) Water is not very dense like metals and therefore doesn't conduct heat as readily. 
C) Much of the heat that is added to water is converted to kinetic energy. 
D) None of the energy is stored as potential energy. 
E) none of the above

Question 19

Why is calcium chloride,   , more effective at melting ice than sodium chloride, NaCl?

Accepted Answer

A) Calcium ions are both larger and more highly charged and thus more effective in breaking the ice crystal structure. 
B) Calcium ions are smaller than sodium ions and thus more able to get in the way of the water molecules attempting to form the solid state lattice. 
C) Calcium chloride produces three ion particles while sodium chloride produces only two. Greater numbers of ions are more effective at decreasing the number of water molecules entering the solid phase. 
D) Sodium ion is a natural water softener and therefore not as effective in inhibiting the formation of the solid state of water from the liquid. 
A) Calcium ions are both larger and more highly charged and thus more effective in breaking the ice crystal structure. 
B) Calcium ions are smaller than sodium ions and thus more able to get in the way of the water molecules attempting to form the solid state lattice. 
C) Calcium chloride produces three ion particles while sodium chloride produces only two. Greater numbers of ions are more effective at decreasing the number of water molecules entering the solid phase. 
D) Sodium ion is a natural water softener and therefore not as effective in inhibiting the formation of the solid state of water from the liquid.

Question 20

What happens to the temperature of something while it is boiling?

Accepted Answer

A) temperature stays the same 
B) temperature drops 
C) temperature increases 
D) Boiling is a cooling process, so temperature should decrease. 
E) Boiling requires energy, so the temperature should go up. 
A) temperature stays the same 
B) temperature drops 
C) temperature increases 
D) Boiling is a cooling process, so temperature should decrease. 
E) Boiling requires energy, so the temperature should go up.

Why do ice cubes get smaller when left in the freezer for a long time?

Water will boil spontaneously in a vacuum. Could you cook an egg in this boiling water?

Suppose that water is used in a thermometer instead of mercury. If the temperature is at 4°C and then changes, why can't the thermometer indicate whether the temperature is rising or falling?

Like water, hydrogen fluoride, HF, and ammonia, N , have relatively high boiling points. Explain.

How are pressure and the boiling point of a compound related?

What would happen to the oceans if the atmosphere suddenly disappeared?

Which of the following statements describes what happens when a given mass of a liquid starts to expand?

Why are drops of water shaped like spheres?

Why does evaporation cool a liquid?

Why is condensation a warming process? What does condensation warm?

Which of the following describes what happens when you increase the temperature of water?

Given the following specific heats, which would require the greatest amount of heat energy to increase its temperature by 50°C?

What is the gas found within a bubble of boiling water?

The specific heat of a substance is the ________.

If it takes 200 J to raise the temperature of a 10-gram block of ice by 10°C, what is the specific heat of the ice?

What happens to the freezing temperature of a salt water solution as it becomes more concentrated?

Evaporation is ________.

Why does water have a high specific heat?

Why is calcium chloride, , more effective at melting ice than sodium chloride, NaCl?

What happens to the temperature of something while it is boiling?

About Science

Particles of Matter

Elements of Chemistry

Subatomic Particles

The Atomic Nucleus

How Atoms Bond

How Molecules Mix

How Chemicals React

Acids and Bases in Our Environment

Oxidations and Reductions Charge the World

Organic Compounds

Nutrients of Life

Medicinal Chemistry

Optimizing Food Production

Protection Water and Air Resources

Capturing Energy

Filters

Exam 8: How Water Behaves

Why do ice cubes get smaller when left in the freezer for a long time?

Water will boil spontaneously in a vacuum. Could you cook an egg in this boiling water?

Suppose that water is used in a thermometer instead of mercury. If the temperature is at 4°C and then changes, why can't the thermometer indicate whether the temperature is rising or falling?

Like water, hydrogen fluoride, HF, and ammonia, N , have relatively high boiling points. Explain.

How are pressure and the boiling point of a compound related?

What would happen to the oceans if the atmosphere suddenly disappeared?

Which of the following statements describes what happens when a given mass of a liquid starts to expand?

Why are drops of water shaped like spheres?

Why does evaporation cool a liquid?

Why is condensation a warming process? What does condensation warm?

Which of the following describes what happens when you increase the temperature of water?

Given the following specific heats, which would require the greatest amount of heat energy to increase its temperature by 50°C?

What is the gas found within a bubble of boiling water?

The specific heat of a substance is the ________.

If it takes 200 J to raise the temperature of a 10-gram block of ice by 10°C, what is the specific heat of the ice?

What happens to the freezing temperature of a salt water solution as it becomes more concentrated?

Evaporation is ________.

Why does water have a high specific heat?

Why is calcium chloride, , more effective at melting ice than sodium chloride, NaCl?

What happens to the temperature of something while it is boiling?

About Science

Particles of Matter

Elements of Chemistry

Subatomic Particles

The Atomic Nucleus

How Atoms Bond

How Molecules Mix

How Chemicals React

Acids and Bases in Our Environment

Oxidations and Reductions Charge the World

Organic Compounds

Nutrients of Life

Medicinal Chemistry

Optimizing Food Production

Protection Water and Air Resources

Capturing Energy

Filters