Deck 5: Water for Life

Question 1

Which is the best definition of specific heat?

A)the quantity of heat energy that must be absorbed to cause one gram of a liquid substance to boil
B)the quantity of heat energy that must be absorbed to increase the temperature of one gram of a substance one degree Celsius
C)the boiling point of a liquid substance in degrees Celsius
D)the difference between the freezing point and the boiling point of a substance

Answer 1

the quantity of heat energy that must be absorbed to increase the temperature of one gram of a substance one degree Celsius

Question 2

How many moles of sodium chloride are there in 250 mL of a 1.20 M sodium chloride solution?

A)0.30
B)0.60
C)1.2
D)2.4

Answer 2

0.30

Question 3

What percentage of Earth's water is in the oceans?

A)97.4%
B)50%
C)2.59%
D)0.014%

Answer 3

97.4%

Question 4

Numbers 1 through 4 are used to identify four different elements.Based on periodic table trends,which number identifies the element that is expected to have the greatest tendency to attract a shared pair of electrons?

A)1
B)2
C)3
D)4

Question 5

If the lead concentration in water is 1 ppm,then we should be able to recover 1 mg of lead from ____ L of water.

A)0.01
B)0.1
C)1
D)10

Question 6

The recommended daily requirement of calcium is 1,000 mg.Tap water in a Midwestern city contains approximately 150 mg Ca/L.A person living in the city who drinks two liters of water in one day would receive ________ percent of his/her RDA of calcium.

A)3
B)7.5
C)15
D)30

Question 7

"Hard" water in parts of the Midwest may have a calcium ion concentration as high as 400 ppm.What is this calcium ion concentration when expressed as a percentage?

A)40%
B)4%
C)0.4%
D)0.04%

Question 8

Electronegativity

A)is a relative measure of an atom's attraction for electrons it shares in a covalent bond.
B)is the total negative charge on a polyatomic anion.
C)is the same for all of the elements in a family or group.
D)decreases from left to right across a period on the periodic table.

Question 9

The fact that carbon (C)is less electronegative than nitrogen (N)means that in a C N bond,the

A)shared electrons are closer to the C atom than to the N atom.
B)shared electrons are closer to the N atom than to the C atom.
C)C atom takes the electrons from the N atom forming C¯ and N⁺.
D)N atom takes the electrons from the C atom forming C⁺ and N¯.

Question 10

A student wants to prepare exactly 250 mL of a 0.500 M aqueous potassium hydroxide solution.What mass of potassium hydroxide (molar mass = 56.10 g/mol)must the student dissolve in the 250 mL of solution?

A)56.1 g
B)28.1 g
C)14.0 g
D)7.01 g

Question 11

What is an aquifer?

A)a holding tank for disinfected water at the municipal water works
B)a water purification system developed by the Romans
C)a large pool of water trapped in sand and gravel below the surface of the earth
D)a solution in which the solvent is water

Question 12

A polar covalent bond is created when

A)a metallic element reacts with a nonmetallic element.
B)two atoms share their bonding electrons unequally.
C)two atoms share three or more electrons.
D)two atoms of the same element form double or triple bonds.

Question 13

The drawing shows two water molecules.Which statement is correct?

A)A: covalent bond;B: hydrogen bond;B is stronger
B)A: hydrogen bond;B: covalent bond;A is stronger
C)A: covalent bond;B: hydrogen bond;A is stronger
D)A: hydrogen bond;B: covalent bond;B is stronger

Question 14

Which molecule(s)contain(s)polar covalent bonds,but is(are)nonpolar?

A)I only
B)III only
C)II and IV only
D)I and III only

Question 15

What is the molarity of sodium chloride in a solution containing 0.50 mol of sodium chloride in 500 mL of water?

A)0.25 M
B)0.50 M
C)1.0 M
D)5.0 M

Question 16

Generally,the water that has the least harmful contaminants is

A)water from the oceans.
B)surface water from lakes.
C)groundwater from aquifers.
D)surface water from rivers.

Question 17

Which correctly describes groundwater?

A)any water found above ground in lakes and rivers;usually needs treatment to remove harmful contaminants
B)any water found above ground in lakes and rivers;usually free of harmful contaminants
C)any water taken from aquifers
D)none of the above.

Question 18

A 4-L sample of water contains 80 µg of lead.What is this lead concentration,in parts per billion (ppb)?

A)20
B)80
C)320
D)500

Question 19

In general,hydrogen bonds are

A)about ten times stronger than typical covalent bonds.
B)about 1/10 as strong as typical covalent bonds.
C)found in every molecule containing more than one hydrogen atom.
D)found only between H atoms in molecules like H₂.

Question 20

In general,hydrogen bonds are ____ and _____ typical covalent bonds.

A)longer than;about one tenth as strong as
B)shorter than;about one tenth as strong as
C)longer than;about ten times as strong as
D)shorter than;about ten times as strong as

Question 21

A 0.25 M solution of the sugar sucrose,C₁₂H₂₂O₁₁,in water is tested for conductivity using the type of apparatus shown.What do you predict will happen?

A)The bulb will not light up.Sucrose is an electrolyte,but not very soluble in aqueous solution.
B)The bulb will not light up.Sucrose is in the molecular form in aqueous solution.
C)The light bulb will shine dimly.Sucrose is only partially ionized in aqueous solution.
D)The light bulb will shine brightly.Sucrose is highly ionized in aqueous solution.

Question 22

Which best symbolizes the hydrogen bonding between two water molecules?

A)
B)
C)
D)

Question 23

What is the correct name for (NH₄)₂CO₃?

A)biammonium carbonate
B)ammonium bicarbonate
C)ammonium carboxide
D)ammonium carbonate

Question 24

Which shows the Lewis structure of water with the correct partial charges and nonbonding electrons?

A)
B)
C)
D)

Question 25

Which statement is not true?

A)In forming a solution,the solute dissolves other substances that are called solvents.
B)Water is the solvent in an aqueous solution.
C)Pure water does not conduct electricity.
D)Electrolytes dissolved in water produce a solution that can conduct electricity.

Question 26

Which is the best representation of the solvation of a sodium cation in water?

A)
B)
C)
D)

Question 27

The formula for a sulfate ion is SO₄²¯.What is the formula of gallium (Ga)sulfate?

A)GaSO₄
B)Ga₂SO₄
C)Ga₂(SO₄)₃
D)Ga₃(SO₄)₂

Question 28

Most polyatomic ions

A)have a negative charge.
B)are composed of a total of two atoms.
C)are cations.
D)contain sulfur atoms.

Question 29

The correct name for CuO is

A)copper oxide.
B)monocopper oxide.
C)copper(I)oxide.
D)copper(II)oxide.

Question 30

Which is the correct Lewis structure of a chlorine atom and the ion that chlorine forms?

A)
B)
C)
D)

Question 31

Water has one of the highest specific heats of any known liquid.This means that the temperature of a water sample _____ with the input of a _____ amount of energy.

A)decreases greatly;small
B)decreases only slightly;large
C)increases only slightly;large
D)increases greatly;small

Question 32

The numbers 1 through 4 are used to identify four different elements on the periodic table.Which element is expected to have 2+ charge when it forms an ion?

A)1
B)2
C)3
D)4

Question 33

Which is not a consequence of hydrogen bonding between water molecules?

A)Water has a high boiling point.
B)Ice floats on water.
C)Water has a high specific heat.
D)Water is colorless and odorless.

Question 34

Which is the correct formula (including charge)of a nitrate ion?

A)NO₂⁺
B)NO₂¯
C)NO₃¯
D)NO₃⁺

Question 35

When the ________molecules of ethanol,C₂H₅OH,are added to water,the ethanol molecules

A)nonpolar;are attracted to the nonpolar water molecules.
B)polar;form hydrogen bonds with the polar water molecules.
C)polar;form covalent bonds with the polar water molecules.
D)nonpolar;are not attracted to the polar water molecules.

Question 36

Which corresponds to the composition of the ion typically formed by magnesium?

A)A
B)B
C)C
D)D

Question 37

A 0.25 M aqueous solution of potassium chloride,KCl,is tested for conductivity using the type of apparatus shown.What do you predict will happen?

A)The bulb will not light up.KCl is a nonelectrolyte.
B)The bulb will not light up.KCl is in the molecular form when dissolved in water.
C)The light bulb will shine dimly.KCl is only partially ionized in aqueous solution.
D)The light bulb will shine brightly.KCl is highly ionized in aqueous solution.

Question 38

What is the formula of the ionic compound formed from magnesium,Mg,and chlorine,Cl?

A)MgCl
B)Mg₂Cl₂
C)Mg₂Cl
D)MgCl₂

Question 39

How many joules are required to heat 2.0 L of water from 20°C to its boiling point of 100°C? The specific heat of water is 4.18 J/g•°C and the density of water is 1 g/mL.

A)6.7 × 10⁵ J
B)1.7 × 10⁵ J
C)3.8 × 10⁴ J
D)6.7 × 10² J

Question 40

Which corresponds to the composition of the ion typically formed by fluorine?

A)A
B)B
C)C
D)D

Question 41

Which of the following is/are true about Maximum Contaminant Level Goals (MCLGs)?
I.The MCLG for any contaminant that is regulated as a carcinogen is set to zero.
II.An average person weighing 70 kg (154 lb)could drink two liters (about two quarts)of water containing a contaminant at the MCGL level every day for 70 years without suffering any ill effects.
III.The Maximum Contaminant Level (MCL)set by the EPA may be higher than the MCLG to account for the financial and technical barriers that may make achieving these goals difficult.
IV.The MCLG for a contaminant is always set to zero because this is the best way to protect human health.

A)II only
B)I and II only
C)I,II,and III only
D)I,II,III,and IV

Question 42

Which is not a form of chlorine used to disinfect water?

A)chlorine gas
B)chloroform
C)sodium hypochlorite
D)calcium hypochlorite

Question 43

When table sugar (sucrose,C₁₂H₂₂O₁₁)dissolves in water,which type(s)of attraction between water and sugar molecules occur(s)?
I.hydrogen bonding
II.polar-polar interactions
III.covalent bonding

A)I and II only
B)II and III only
C)I and III only
D)I,II,and III

Question 44

At water treatment plants aluminum sulfate and calcium hydroxide are added to

A)neutralize excess ozone.
B)neutralize excess chlorine.
C)remove suspended clay and dust particles.
D)neutralize excess acidity or basicity.

Question 45

Potable water is water that

A)contains residual chlorine.
B)is fit for human consumption.
C)is contaminated with lead.
D)contains too much residual ozone to be drinkable.

Question 46

Which of these is not a trihalomethane?

A)CHCl₃
B)CH₃Cl
C)CHF₃
D)CHBr₂Cl

Question 47

The EPA regulates the presence of nitrates and nitrites in food because

A)they produce nitrogen in the blood,causing a condition similar to the bends deep sea divers can suffer from.
B)as with ammonium nitrate fertilizers,they may cause small explosions in blood vessels causing them to rupture.
C)they interact with naturally occurring ozone in the body and remove it from the circulatory system.
D)they interact with the blood and limit its ability to transport oxygen.

Question 48

The attractions between anions and cations throughout a crystal are known collectively as

A)covalent bonds.
B)polar covalent bonds.
C)hydrogen bonds.
D)ionic bonds.

Question 49

Which ions,if present in drinking water,would pose a significant health risk?
i.Pb²⁺
II.Hg²⁺
III.Cd²⁺
IV.Ca²⁺

A)I,II,and III only
B)II,III,and IV only
C)I,III,and IV only
D)I,II,III,and IV

Question 50

The main reason that water supplies are "chlorinated" is

A)to produce gels that remove solids from the water.
B)to kill disease-causing organisms in the water.
C)to soften the water.
D)to precipitate lead salts from the water as insoluble lead chloride.

Question 51

Reverse osmosis is illustrated in this diagram.What is this process used for?

A)to purify water by ion exchange
B)to remove dissolved salts from sea water
C)for the ozonation of water supplies
D)to add fluorine to municipal water supplies

Question 52

Which compound is insoluble in water?

A)sodium carbonate
B)potassium nitrate
C)ammonium chloride
D)calcium carbonate

Question 53

Which form of water disinfection continues to provide antibacterial protection after the water leaves the purification plant?

A)chlorination
B)ozonation
C)UV radiation
D)filtration

Question 54

We cannot effectively clean nonpolar substances from our hands or clothing with water alone;we must add soap or detergent.The structure of a typical soap molecule is shown below.Which region of this molecule would dissolve in a nonpolar substance such as grease?

A)Region 1
B)Region 2
C)Region 3
D)Region 4

Question 55

Which compounds are not soluble in water at room temperature?

A)I and II only
B)II and III only
C)III and IV only
D)I and IV only

Question 56

The steps in the typical purification processes for municipal drinking water are,in order,

A)filtration,distillation,chlorination,and filtration.
B)filtration,chlorination,ozonation,and flocculation.
C)filtration,flocculation,filtration,and chlorination.
D)flocculation,filtration,UV irradiation,and filtration.

Question 57

Which compound should be the most soluble in water?

A)
B)
C)
D)

Question 58

Which statement is not correct?

A)Lead has been used in water pipes since ancient times because it is an abundant,soft,and easily worked metal that does not rust.
B)The symbol for lead,Pb,comes from the Latin name for lead "plumbum".
C)When ingested,lead causes severe and permanent neurological problems in humans.
D)The EPA estimates that one in two U.S.children under six years of age has a blood lead level above the acceptable level of 15 g/mL.

Question 59

What are the major disadvantages of using ozone instead of chlorine to disinfect water?

A)Ozonation is more expensive than chlorination and ozone leaves an odor in the water.
B)Ozonation causes trihalomethane formation and leaves an odor in the treated water.
C)Ozonation causes trihalomethane formation and is more expensive than chlorination.
D)Ozone does not provide long-term protection against waterborne viruses because it decomposes quickly and it is more expensive than chlorination.

Question 60

A disadvantage of ozonation over chlorination is

A)the higher cost of ozonation.
B)ozonation does not protect the water after the initial process is complete.
C)the higher cost of ozonation and ozonation does not protect the water after the initial process is complete.
D)None of these choices is correct.

Question 61

Which of the following are methods of making sea water appropriate for drinking?
__ Osmosis
__ Reverse osmosis
__ Distillation
__ Flocculation

Question 62

What is biological oxygen demand (BOD)?

A)A measure of the amount of dissolved oxygen microorganisms use up as they decompose organic wastes found in water.
B)A measure of the amount of dissolved oxygen necessary to purify wastewater.
C)A measure of the phosphate ion concentration of water
D)A measure of nitrate ion concentration of water.

Question 63

Which compound has an incorrect formula?

A)MgPO₄
B)(NH₄)₂S
C)Mg(HSO₃)₂
D)NaClO₄

Question 64

The world map shows the availability of safe drinking water around the world.Which statement is true?

A)In Australia,less than 75% of the population has access to safe drinking water.
B)In most of Africa,more than 90% of the population has access to clean water.
C)In Europe and Russia,more than 10% of the population does not have access to clean water.
D)In the United States and Canada,more than 90% of the population has access to clean water.

Question 65

Which compound has a correct formula?

A)CaSO₃
B)Ca₂SO₄
C)Mg(CO₃)₂
D)Na₂PO₄

Question 66

The drawing shows a simple way of purifying salt water.What is this process called?

A)filtration
B)distillation
C)ozonation
D)chlorination

Question 67

A 2- ion has 36 electrons and 45 neutrons.What is its correct symbol?

A)(⁸³Sr^2-)
B)(⁷¹Br^2-)
C)(⁷⁹Se ^2-)
D)(⁷⁸As ^2-)

Question 68

How many bromide ions will combine with one ion of aluminum?

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

Question 69

Why is water a liquid a room temperature instead of a gas?

A)It is a gas a room temperature.
B)Water has hydrogen bonds between the molecules.
C)Water is very acidic.
D)Water is a good solvent.

Question 70

Which of the following has the highest MCL in drinking water in the US?

A)Nitrates
B)Trihalomethanes
C)Lead
D)Mercury

Question 71

Which of the following is not a consequence of biomagnification?

A)Consumption of tuna should be limited.
B)DDT from fish was killing large birds before the pesticide was banned.
C)Lead in water can lead to brain damage in children.
D)Polar compounds are found in high concentrations in predator animals.

Question 72

Mixing which of the following will produce a precipitation reaction (give an insoluble product)?

A)HNO₃ (aq)and Sr(OH)₂(aq)
B)LiNO₃ and NaI
C)Na₂SO₄(aq)and Ba(OH)₂(aq)
D)NaOH and KBr

Question 73

The MCL for drinking water is the legal limit for the concentration of a contaminant expressed in ppm or ppb.This is always a lower concentration than the MCLG value for the same contaminant.

Question 74

Which type of water may be considered pure?

A)bottled water
B)filtered water
C)distilled water
D)chlorinated water