Deck 2: The Chemical Basis of Life

Question 1

Which of the following statements about acid precipitation is false?

A)Acid precipitation has little or no effect on soil chemistry.
B)Acid precipitation is defined as having a pH below 5.6.
C)Acid precipitation is primarily the result of burning fossil fuels.
D)Acid precipitation damages natural wilderness areas.

Answer 1

A

Question 2

Which of the following is dependent on the ability of water molecules to form hydrogen bonds with other molecules besides water?

A)the universality of water as a solvent
B)the milder temperatures of coastal regions compared to inland areas
C)the evaporative cooling of skin surfaces
D)the ability of certain insects to walk on the surface of water

Answer 2

A

Question 3

You've made a hot drink by dissolving a teaspoon of instant coffee and a teaspoon of sugar in a cup of hot water.Which of the following statements is true?

A)The water is the solute portion of the drink.
B)The instant coffee and sugar dissolve because they have no charged regions to repel the partial positive and partial negative regions of the water molecules.
C)The instant coffee and sugar are solvents.
D)You've just prepared an aqueous solution.

Answer 3

D

Question 4

A water molecule (H-O-H)is held together by

A)two polar covalent bonds.
B)a single covalent bond.
C)hydrogen bonds.
D)a double covalent bond.

Question 5

In a water molecule,hydrogen and oxygen are held together by a(n)bond.

A)nonpolar covalent
B)polar covalent
C)double covalent
D)hydrogen

Question 6

When full,the innermost electron shell of argon contains electrons,and the outermost shell contains electrons.

A)2 ...2
B)4 ...8
C)2 ...8
D)8 ...8

Question 7

The body uses atoms in different ways to accomplish different tasks.For example,one portion of the body's calcium supply strengthens bones,whereas another portion combines with proteins to stimulate blood clotting after tissue injury.Which of the statements that follow provides the most logical chemical explanation of calcium's ability to perform such different functions?

A)There are many different isotopes of calcium,and the most reactive isotope is found in the bone.
B)The bone contains calcium salts,which are less reactive than the calcium ions found in the blood.
C)The calcium in blood is a more reactive form of the atom and therefore has fewer protons than the calcium in bone.
D)The calcium in blood has a lighter atomic mass than the calcium in bone and is in a more reactive form.

Question 8

The temperature of evaporation is much higher for water than for alcohol.Without knowing more about the chemistry of alcohol,which of the following is the most logical chemical explanation for this phenomenon?

A)Ionic bonds form between alcohol molecules.These are the weakest type of bond and are easier to break than the hydrogen bonds between water molecules.
B)Alcohol molecules are more cohesive than water molecules.This means that as alcohol molecules evaporate,they pull other alcohol molecules into the air along with them.
C)Fewer hydrogen bonds form between alcohol molecules.As a result,less heat is needed for alcohol molecules to break away from solution and enter the air.
D)Alcohol has a higher surface tension than water.This means that alcohol molecules can easily break away from other alcohol molecules and evaporate at a lower temperature.

Question 9

In the equation 2 H2 + O2 -2 H2O,

A)H2,O2,and H2O are all elements.
B)only H2 and O2 are compounds.
C)only H₂O is a compound.
D)H₂,O₂,and H₂O are all compounds.

Question 10

The sodium atom contains 11 electrons,11 protons,and 12 neutrons.What is the mass number of sodium?

A)11
B)34
C)22
D)23

Question 11

In some areas,fluoride is added during the municipal water treatment process in order to help

A)prevent the development of mental retardation
B)reduce tooth decay
C)prevent the growth of bacteria
D)prevent goiter

Question 12

Which of the following statements about water is false?

A)If ice sank,the oceans would eventually freeze solid.
B)Floating ice on a pond insulates the liquid water below,slowing its rate of freezing.
C)Ice is more dense than liquid water.
D)Water naturally exists in all three physical states on Earth.

Question 13

Which of the following statements regarding chemical reactions is false?

A)Chemical reactions involve the making and breaking of chemical bonds.
B)Although the atoms of a reaction's reactants and products are identical to each other,their molecular formulae differ.
C)Some chemical reactions create electrons; others destroy them.
D)The reactants contain the same number of atoms as the products.

Question 14

Electrons move about the nucleus of an atom in the same way that

A)birds migrate to a new winter home.
B)boats cross a lake.
C)insects fly around a bright lamp at night.
D)cars are parked along the sides of a street.

Question 15

Which of the following particles is found in the nucleus of an atom?

A)only protons
B)only electrons
C)protons and electrons
D)protons and neutrons

Question 16

The hydrogen atoms of a water molecule are bonded to the oxygen atom by _ bonds,whereas neighboring water molecules are held together by bonds.

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

Question 17

are weak bonds that are not strong enough to hold atoms together to form molecules but are strong enough to form bonds within and around large molecules.

A)Polar covalent bonds
B)Hydrogen bonds
C)Ionic bonds
D)Covalent bonds

Question 18

A buffer

A)donates H+ ions when conditions become too basic and accepts H+ ions when conditions become too acidic.
B)is a base that is used to offset overly acidic conditions in the body.
C)is an acid that is used to offset overly basic conditions in the body.
D)donates OH- ions when conditions become too basic and accepts OH- ions when conditions become too acidic.

Question 19

Compared to a solution of pH 3,a solution of pH 1 is

A)100 times more acidic.
B)10 times more basic.
C)10 times more acidic.
D)100 times more basic.

Question 20

What happens to an atom if the electrons in the outer shell are altered?

A)The atom will disintegrate.
B)The atom's characteristics change and it becomes a different element.
C)The properties of the atom will change.
D)The atom becomes radioactive.

Question 21

Which of the following trace elements needed by humans is commonly added to table salt?

A)magnesium
B)iodine
C)fluoride
D)iron

Question 22

Which of the following statements regarding matter is false?

A)All matter exists in the form of compounds.
B)All matter is composed of elements.
C)All matter has mass.
D)All life is composed of matter.

Question 23

What is the atomic mass of an atom that has 6 protons,6 neutrons,and 6 electrons?

A)18
B)6
C)8
D)12

Question 24

A diabetic,who does not utilize insulin properly,will metabolize fats instead of glucose.A condition called diabetic ketoacidosis is a common result of excessive fat metabolism,causing blood pH values of 7.1 or less (normal range = 7.35-7.45).What has happened to the blood pH and why?

A)The pH is below normal (acidic)because the buffering capacity was exceeded.
B)The pH is above normal (basic)because the ketones are too basic.
C)The pH is not affected because the blood buffers can absorb the excess H+.
D)The pH is below normal because buffers can donate OH+.

Question 25

Table salt is formed when

A)sodium and chlorine share electrons to form a bond.
B)sodium donates its single outer electron to chlorine.
C)chlorine gives an electron to sodium.
D)a hydrogen bond forms between sodium and chlorine.

Question 26

Medicines are often administered in pill form.In many cases,the active ingredient of the pill (the drug)is joined to another substance by .This forms a(n)_,which is stable in the dry environment of a pill bottle but dissociates under the wet conditions of the digestive system to release the drug to the body.

A)hydrogen bonds ...base
B)ionic bonds ...salt
C)ionic bonds ...acid
D)covalent bonds ...salt

Question 27

Which of the following best describes the atomic number of an atom?

A)the number of electrons in the atom
B)the number of neutrons in the atom
C)the number of protons,electrons,and neutrons in the atom
D)the number of protons in the atom

Question 28

Which of the following statements best describes a compound?

A)A compound is exemplified by sodium.
B)A compound is a solution.
C)A compound is a pure element.
D)A compound contains two or more different elements in a fixed ratio.

Question 29

Water's surface tension and heat storage capacity is accounted for by its

A)size.
B)orbitals.
C)mass.
D)hydrogen bonds.

Question 30

A solution with a pH of 7 is

A)strongly acidic.
B)neutral.
C)weakly basic.
D)weakly acidic.

Question 31

An uncharged atom of boron has an atomic number of 5 and an atomic mass of 11.How many electrons does boron have?

A)2
B)5
C)11
D)15

Question 32

The tendency of water molecules to stick together is referred to as

A)polarity.
B)adhesion.
C)cohesion.
D)transpiration.

Question 33

Which of the following is another term used for atomic mass?

A)mendel
B)calvin
C)dalton
D)darwin

Question 34

Which of the following statements about radioactive isotopes is true?

A)The nuclei of radioactive isotopes are unusually stable,but the atoms tend to lose electrons.
B)Radioactive elements are natural and therefore not harmful.
C)The energy emitted by radioactive isotopes can break chemical bonds and cause molecular damage in cells.
D)When given a choice between radioactive and nonradioactive isotopes of the same atom,living cells are more likely to incorporate the radioactive isotopes into their structures.

Question 35

Household ammonia has a pH of 12; household bleach has a pH of 13.Which of the following statements about them is true?

A)The ammonia has 10 times as many OH- ions as the bleach.
B)A solution that could buffer the bleach and ammonia would remove excess OH- ions.
C)Both of these substances are strong acids.
D)The ammonia has 10 times as many H+ ions as the bleach.

Question 36

Photosynthesis requires many steps to make glucose.As a result of the synthesis process,

A)more atoms are present at the beginning than at the end.
B)all the carbons from the six carbon dioxide atoms are found in glucose.
C)more carbon dioxide is released from the plant than is absorbed.
D)water is synthesized by the plant from H2 and O2.

Question 37

In the equation 2 H2 + O2 -2 H2O,the H2 molecules are and the H2O molecules are .

A)created ...destroyed
B)reactants ...products
C)products ...reactants
D)used ...stored

Question 38

Which of the following would be considered an effective way to decrease the production of acid precipitation?

A)Build more coal- generated electricity power plants.
B)Drive more full- size SUVs.
C)Whenever possible,walk or ride a bicycle instead of driving a car.
D)Discourage the use of alternative energy resources such as solar,wind,and geothermal energy.

Question 39

If you found a fossilized dinosaur bone,what method could be used to determine the age of the fossil?

A)electrophoresis
B)radial immunodiffusion
C)DNA fingerprinting
D)isotope analysis

Question 40

Which of the following statements about pH is true?

A)A single unit change on the pH scale is equivalent to a 1% change in hydrogen ion concentration.
B)Basic pH levels are less than 7.
C)The pH scale is a measure of oxygen ion concentration.
D)An increase in hydrogen ion concentration means a decrease in pH scale units.

Question 41

Radioactive isotopes

A)are never incorporated into organic compounds.
B)can be used in conjunction with PET scans to diagnose diseases.
C)do not occur naturally.
D)are frequently added to foods as nutritional supplements.

Question 42

What change is occurring in this figure?

A)Sodium is filling its third electron shell.
B)Chlorine is filling its third electron shell.
C)Sodium is becoming negatively charged.
D)Chlorine is losing an electron.

Question 43

The four most common elements in living organisms are

A)C,H,O,Na.
B)C,N,O,Na.
C)C,H,O,N.
D)C,H,O,Fe.

Question 44

A hydrogen atom has one electron.How many covalent bonds can hydrogen form?

A)one covalent bond
B)four covalent bonds
C)no covalent bonds
D)two covalent bonds

Question 45

A pharmaceutical company hires a chemist to analyze the purity of the water being used in its drug preparations.If the water is pure,the chemist would expect to find

A)only H+ ions and OH- ions.
B)H2O molecules,H+ ions,and OH- ions.
C)only molecules of H₂O.
D)H₂O molecules and H⁺ ions.

Question 46

A radioactive isotope is an isotope that

A)is stable.
B)has more protons than the common variant of the element.
C)decays.
D)has the same atomic mass,but a different atomic number than the common variant of the element.

Question 47

The emission of and _ _ are primarily responsible for acid precipitation.

A)carbon dioxide ...ozone
B)halones ...CFCs
C)nitrogen oxides ...sulfur oxides
D)carbon dioxide ...methane

Question 48

Which of the following hypotheses would be supported if liquid water were found on Mars and contained evidence of bacteria- like organisms?

A)Life on Earth must have originated on Mars.
B)The chemical evolution of life is possible.
C)Life is guided by intelligent design.
D)Life must evolve in the presence of oxygen.

Question 49

Which of the following statements regarding the oxygen atom of a water molecule is true?

A)Oxygen is more positively charged than the hydrogen atoms.
B)Oxygen is attracted to the negatively charged atoms of other molecules.
C)Oxygen is more electronegative than the hydrogen atoms.
D)Oxygen attracts electrons less strongly than the hydrogen atoms.

Question 50

A(n)forms when two atoms share electrons.

A)hydrogen bond
B)ion
C)ionic bond
D)covalent bond

Question 51

The hydrogen bonds shown in this figure are each

A)between an oxygen and a hydrogen atom of the same water molecule.
B)between an oxygen and a hydrogen atom of different water molecules.
C)between two atoms with the same charge.
D)between two hydrogen atoms.

Question 52

Typically,nitrogen atoms are composed of electrons,protons,and neutrons.An isotope of nitrogen could

A)have more protons than the usual nitrogen atom.
B)have more neutrons than the usual nitrogen atom.
C)be positively charged.
D)be negatively charged.

Question 53

What is the fundamental difference between covalent and ionic bonding?

A)In covalent bonding,both partners end up with filled outer electron shells; in ionic bonding,one partner does and the other does not.
B)Covalent bonding involves only the outermost electron shell; ionic bonding also involves the next electron shell inside the outermost shell.
C)In a covalent bond,the partners share a pair of electrons; in an ionic bond,one partner accepts electrons from the other.
D)Covalent bonds form between atoms of the same element; ionic bonds form between atoms of different elements.

Question 54

Clot formation in our blood can lead to a heart attack or stroke.What was altered in the proteins that made the clot?

A)The blood was saturated with proteins.
B)The proteins became more soluble in the blood.
C)The proteins became more polar.
D)The proteins were no longer soluble in the blood.

Question 55

Which of the following is a trace element in the human body?

A)hydrogen
B)nitrogen
C)oxygen
D)zinc

Question 56

Water molecules stick to other water molecules because

A)covalent bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules.
B)the oxygen atoms of adjacent water molecules are attracted to one another.
C)water molecules are neutral,and neutral molecules are attracted to each other.
D)hydrogen bonds form between the hydrogen atoms of one water molecule and the oxygen atoms of other water molecules.