Question 1

Treating water with chlorine or ozone during water purification is an example of

Accepted Answer

A) a physical change. 
B) a chemical reaction. 
C) ion exchange. 
D) a solid dissolving in a liquid. 
E) only a and b 
A) a physical change. 
B) a chemical reaction. 
C) ion exchange. 
D) a solid dissolving in a liquid. 
E) only a and b

Question 2

Suggest why sodium chloride,NaCl,is insoluble in gasoline.Consider the electrical attractions.

Accepted Answer

A) Since this molecule is so small,there is not much opportunity for the gasoline to interact with it through any electrical attractions. 
B) Since gasoline is a very polar molecule,the salt can only form dipole-induced dipole bonds,which are very weak,giving it a low solubility in gasoline. 
C) Since gasoline is so strongly attracted to itself,the salt,NaCl is excluded. 
D) Salt is composed of ions that are too attracted to themselves.Gasoline is non-polar so salt and gasoline will not interact very well. 
A) Since this molecule is so small,there is not much opportunity for the gasoline to interact with it through any electrical attractions. 
B) Since gasoline is a very polar molecule,the salt can only form dipole-induced dipole bonds,which are very weak,giving it a low solubility in gasoline. 
C) Since gasoline is so strongly attracted to itself,the salt,NaCl is excluded. 
D) Salt is composed of ions that are too attracted to themselves.Gasoline is non-polar so salt and gasoline will not interact very well.

Question 3

What happens if you were to place a concentrated solution into a bag made of a semipermeable membrane and were to then suspend it in a very dilute solution?

Accepted Answer

A) The size of the suspended bag would decrease. 
B) The size of the suspended bag would increase. 
C) The size of the bag would not change. 
D) The solutions would eventually reach the same concentration. 
E) only c and d 
A) The size of the suspended bag would decrease. 
B) The size of the suspended bag would increase. 
C) The size of the bag would not change. 
D) The solutions would eventually reach the same concentration. 
E) only c and d

Question 4

What is the first step in treating raw sewage?

Accepted Answer

A) filtration of solids 
B) removal of fine particles by settling 
C) removal of grit by settling 
D) removal of sludge 
E) disinfection 
A) filtration of solids 
B) removal of fine particles by settling 
C) removal of grit by settling 
D) removal of sludge 
E) disinfection

Question 5

Which of the following would be considered a heterogeneous mixture?

Accepted Answer

A) salad dressing 
B) water 
C) milk 
D) vegetable oil 
E) vinegar 
A) salad dressing 
B) water 
C) milk 
D) vegetable oil 
E) vinegar

Question 6

Which of the following is not a typical use for potable water?

Accepted Answer

A) irrigation 
B) cooking in a pot 
C) flushing a toilet 
D) drinking 
E) boiling 
A) irrigation 
B) cooking in a pot 
C) flushing a toilet 
D) drinking 
E) boiling

Question 7

How can you tell whether a sugar solution is saturated or not?

Accepted Answer

A) Add more sugar,if it dissolves,it is saturated. 
B) There will be a precipitate if the water is heated. 
C) Cool the solution to see if there is a precipitate. 
D) As long as there are more water molecules than sugar molecules,there is a saturated solution. 
A) Add more sugar,if it dissolves,it is saturated. 
B) There will be a precipitate if the water is heated. 
C) Cool the solution to see if there is a precipitate. 
D) As long as there are more water molecules than sugar molecules,there is a saturated solution.

Question 8

What is the easiest way to eliminate organic components?

Accepted Answer

A) Aerate the solution and let bacteria consume the organics. 
B) Treat the solution with UV radiation. 
C) Filter the solution through activated carbon filters. 
D) Use reverse osmosis. 
E) all of the above 
A) Aerate the solution and let bacteria consume the organics. 
B) Treat the solution with UV radiation. 
C) Filter the solution through activated carbon filters. 
D) Use reverse osmosis. 
E) all of the above

Question 9

What is an advantage of using chlorine gas to disinfect drinking water supplies?

Accepted Answer

A) It provides residual protection against pathogens. 
B) It gives the water a fresh taste. 
C) Residual chlorine in water helps to whiten teeth. 
D) Excess chlorine is absorbed in our bodies as a mineral supplement. 
A) It provides residual protection against pathogens. 
B) It gives the water a fresh taste. 
C) Residual chlorine in water helps to whiten teeth. 
D) Excess chlorine is absorbed in our bodies as a mineral supplement.

Question 10

A combination of two or more substances in which they no longer retain their chemical properties is called a(n)

Accepted Answer

A) mixture. 
B) compound. 
C) heterogeneous mixture. 
D) periodic trend. 
E) suspension. 
A) mixture. 
B) compound. 
C) heterogeneous mixture. 
D) periodic trend. 
E) suspension.

Question 11

How would you classify the following material? swimming pool water

Accepted Answer

A) homogeneous mixture 
B) heterogeneous mixture 
C) a pure element 
D) a pure compound 
E) depends on how many children have been in it 
A) homogeneous mixture 
B) heterogeneous mixture 
C) a pure element 
D) a pure compound 
E) depends on how many children have been in it

Question 12

Cells at the top of a tree have a higher concentration of sugars than cells at the bottom.How might this fact assist a tree in moving water upward from its roots?

Accepted Answer

A) Cells with high concentrations of sugar are more dense.As these cells migrate downwards,cells containing fresh water are able to migrate upwards. 
B) Water is pushed upwards by osmostic pressure. 
C) It doesn't.In fact,water makes it to the top of a tree because that is where the water molecules are being evaporated. 
D) Fresh water is drawn upwards to the sugar containing cells by way of dipole-dipole molecular interactions. 
A) Cells with high concentrations of sugar are more dense.As these cells migrate downwards,cells containing fresh water are able to migrate upwards. 
B) Water is pushed upwards by osmostic pressure. 
C) It doesn't.In fact,water makes it to the top of a tree because that is where the water molecules are being evaporated. 
D) Fresh water is drawn upwards to the sugar containing cells by way of dipole-dipole molecular interactions.

Question 13

If you need 3.01 × 1023 molecules of sucrose,how many liters of a 4.00 molar solution would you need?

Accepted Answer

A) 0.125 L 
B) 0.250 L 
C) 4.00 L 
D) 1.00 L 
E) none of the above 
A) 0.125 L 
B) 0.250 L 
C) 4.00 L 
D) 1.00 L 
E) none of the above

Question 14

How would you classify the following material? milk

Accepted Answer

A) a suspension 
B) a heterogeneous mixture 
C) a solution 
D) an element 
E) a compound 
A) a suspension 
B) a heterogeneous mixture 
C) a solution 
D) an element 
E) a compound

Question 15

How necessary is soap for removing salt from your hands?

Accepted Answer

A) Soap is necessary because it has both a polar and nonpolar end to interact with the positive and negative ions in the salt. 
B) Soap is necessary because it creates a film on the surface of your skin,shielding it from interacting with the ionic charges of the salt. 
C) Soap is not at all necessary for removing salt from your hands.The strong ion-dipole interactions between fresh water and the salt are most sufficient to lift the salt away from your hands. 
D) Soap is not necessary because there are no electrical charges on the skin of your hands for the salt to interact with. 
A) Soap is necessary because it has both a polar and nonpolar end to interact with the positive and negative ions in the salt. 
B) Soap is necessary because it creates a film on the surface of your skin,shielding it from interacting with the ionic charges of the salt. 
C) Soap is not at all necessary for removing salt from your hands.The strong ion-dipole interactions between fresh water and the salt are most sufficient to lift the salt away from your hands. 
D) Soap is not necessary because there are no electrical charges on the skin of your hands for the salt to interact with.

Question 16

Which of the following might have the best solubility in water?

Accepted Answer

A) CH3OH 
B) Cl2 
C) O2 
D) CH3CH3 
E) none of the above 
A) CH3OH 
B) Cl2 
C) O2 
D) CH3CH3 
E) none of the above

Question 17

Why do red blood cells,which contain an aqueous solution of dissolved ions and minerals,burst when placed in fresh water?

Accepted Answer

A) The dissolved ions provide a pressure that eventually bursts open the cell. 
B) More water molecules enter the cell than leave the cell. 
C) The fresh water acts to dissolve the blood cell wall. 
D) all of the above 
A) The dissolved ions provide a pressure that eventually bursts open the cell. 
B) More water molecules enter the cell than leave the cell. 
C) The fresh water acts to dissolve the blood cell wall. 
D) all of the above

Question 18

How many moles of water are there in 100.grams of water?

Accepted Answer

A) 1800 moles 
B) 100 moles 
C) 0.018 moles 
D) 5.55 moles 
A) 1800 moles 
B) 100 moles 
C) 0.018 moles 
D) 5.55 moles

Question 19

What can be said about drinking water that is 99.9999 percent free of some poison,such as a pesticide?

Accepted Answer

A) In each 10,000 parts of the contaminated water there is one part pesticide and 9999 parts pure water. 
B) In each 100,000 parts of the contaminated water there is one part pesticide and 99,999 parts pure water. 
C) The ratio of water molecules to pesticide molecules in the glass is so great that drinking the water is not problematic. 
D) The water is highly contaminated and surely not fit to drink. 
A) In each 10,000 parts of the contaminated water there is one part pesticide and 9999 parts pure water. 
B) In each 100,000 parts of the contaminated water there is one part pesticide and 99,999 parts pure water. 
C) The ratio of water molecules to pesticide molecules in the glass is so great that drinking the water is not problematic. 
D) The water is highly contaminated and surely not fit to drink.

Question 20

Why is it important to conserve fresh water?

Accepted Answer

A) There is little fresh water available to us on our planet. 
B) As the human population grows,so does our need for fresh water. 
C) It is expensive to purify nonpotable water. 
D) all of the above 
A) There is little fresh water available to us on our planet. 
B) As the human population grows,so does our need for fresh water. 
C) It is expensive to purify nonpotable water. 
D) all of the above

Exam 16: Mixtures

Treating water with chlorine or ozone during water purification is an example of

Suggest why sodium chloride,NaCl,is insoluble in gasoline.Consider the electrical attractions.

What happens if you were to place a concentrated solution into a bag made of a semipermeable membrane and were to then suspend it in a very dilute solution?

What is the first step in treating raw sewage?

Which of the following would be considered a heterogeneous mixture?

Which of the following is not a typical use for potable water?

How can you tell whether a sugar solution is saturated or not?

What is the easiest way to eliminate organic components?

What is an advantage of using chlorine gas to disinfect drinking water supplies?

A combination of two or more substances in which they no longer retain their chemical properties is called a(n)

How would you classify the following material? swimming pool water

Cells at the top of a tree have a higher concentration of sugars than cells at the bottom.How might this fact assist a tree in moving water upward from its roots?

If you need 3.01 × 1023 molecules of sucrose,how many liters of a 4.00 molar solution would you need?

How would you classify the following material? milk

How necessary is soap for removing salt from your hands?

Which of the following might have the best solubility in water?

Why do red blood cells,which contain an aqueous solution of dissolved ions and minerals,burst when placed in fresh water?

How many moles of water are there in 100.grams of water?

What can be said about drinking water that is 99.9999 percent free of some poison,such as a pesticide?

Why is it important to conserve fresh water?

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

How Chemicals React

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

If you need 3.01 × 10²³ molecules of sucrose,how many liters of a 4.00 molar solution would you need?