Deck 2: Lifes Chemical Basis

Question 1

A hydrogen bond is a(n) ____.

A)shared pair of electrons between a hydrogen and an oxygen nucleus
B)shared pair of electrons between a hydrogen nucleus and either an oxygen or a nitrogen nucleus
C)attraction between a covalently bonded hydrogen atom and another atom taking part in a separate polar covalent bond
D)attraction between an ionically bonded hydrogen atom and another atom taking part in a separate polar covalent bond
E)a strong chemical bond between two ions that are each bonded to other polar compounds

Answer 1

C

Question 2

​When nonionic solids dissolve in water, they ____.

A)​act as buffers
B)​accept hydrogen ions
C)​release hyddrogen ions
D)​do not dissociate into atoms
E)​dissociate into atoms

Answer 2

D

Question 3

Water molecules consist of one oxygen atom covalently bonded to two hydrogen atoms. In these covalent bonds, the electrons are pulled toward the oxygen side of the covalent bond, making one side of the molecule slightly negative and the other side of the molecule slightly positive. This characteristic of water is called ____.

A)polarity
B)ionic
C)electronegativity
D)hydrophobicity
E)cohesion

Answer 3

A

Question 4

When dissolved in water, a(n) _____ donates H⁺, while a(n) _____accepts H⁺.

A)acid; base
B)base; acid
C)buffer; solute
D)base; buffer
E)solvent; solute

Question 5

Which type of chemical bond joins the oxygen (atomic number 8) and carbon (atomic number 6) atoms in carbon dioxide (CO₂)?

A)single covalent
B)double covalent
C)triple covalent
D)ionic
E)hydrogen

Question 6

Substances that are ____ give up hydrogen ions when they dissolve in water.

A)basic
B)acidic
C)neutral
D)hydrophobic
E)buffered

Question 7

A salt will dissolve in water to form ____.

A)acids
B)gases
C)ions
D)bases
E)polar solvents

Question 8

Negatively charged subatomic particles are known as ____.

A)neutrons
B)protons
C)electrons
D)elements
E)atoms

Question 9

The process by which a nucleus of an atom breaks up and emits subatomic particles and/or energy is known as ____.

A)radioactive decay
B)radioactive isotoping
C)electronegativity
D)neutron release
E)free radical release

Question 10

Why does ice float on water?

A)Ice is hydrophobic and repels water.
B)Water molecules have less mass as they become colder.
C)Water molecules are spaced farther apart in ice than in liquid water.
D)Vibrating electrons in liquid water push ice to the surface.
E)Hydrogen bonds are weaker in ice.

Question 11

Atoms with unpaired electrons, known as ____, are dangerous because they ____.

A)free radicals; damage biological molecules
B)ions; are unstable
C)radioisotopes; damage electron orbitals
D)free radicals; are inert
E)radioisotopes; cannot fill their electron shells

Question 12

The pH of black coffee is about 5, while the pH of lemon juice is about 2. Lemon juice is therefore approximately ____ times more acidic than black coffee.

A)3
B)2
C)10
D)100
E)1,000

Question 13

Which feature of water allows sheets of ice to form on the surface of lakes, thereby insulating the water below and protecting aquatic organisms during winter?

A)Water has surface tension.
B)Water is an excellent solvent.
C)Water has cohesion.
D)Evaporation requires energy.
E)Water is less dense when solid.

Question 14

Why is pH stability important for homeostasis?

A)There is no mechanism for buffering pH changes in blood.
B)Excess H⁺ disrupts hydrogen bonds, thereby destroying the cohesion between water molecules.
C)Buffers can only work properly within a narrow pH range.
D)Most biological molecules function optimally only within a narrow pH range.
E)Excess H⁺ facilitates hydrogen bonds, which disrupt the structural integrity of biological molecules.

Question 15

What is the pH of a solution in which the number of H⁺ ions equals the number of OH^- ions?

A)0-2
B)3-6
C)7
D)8-10
E)11-14

Question 16

Which type of bond is formed whenever atoms share one pair of electrons?

A)single covalent
B)hydrogen
C)ionic
D)double covalent
E)nonpolar ionic

Question 17

The nucleus of an atom contains ____.

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

Question 18

Cellular pH is kept near a value of seven due to the action of ____ that can ____.

A)salts; dissolve readily in water
B)buffers; alternately donate and accept H⁺
C)buffers; donate H⁺ when the pH decreases
D)bases; donate OH^- when pH rises
E)water; stabilize temperature

Question 19

The mass number of an atom is determined by the number of ____.

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

Question 20

Hydrogen bonds in water collectively exert a continuous pull on its individual molecules; therefore, water molecules resist separating from each other. This property is called ____.

A)ionic bonding
B)solvency
C)polarity
D)hydrophilic tension
E)cohesion

Question 21

Which subatomic particles are arranged in various energy levels or orbitals?

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

Question 22

An atom of which element is the least reactive?

A)hydrogen (atomic number 1)
B)lithium (atomic number 3)
C)chlorine (atomic number 17)
D)argon (atomic number 18)
E)scandium (atomic number 21)

Question 23

Why does the evaporation of sweat effectively cool the body?

A)As sweat cools, the distance between water molecules increases, which further reduces the temperature.
B)Since evaporation requires energy to overcome cohesion, heat energy is removed from the body surface.
C)Water in sweat insulates the skin and absorbs heat from the body before evaporation.
D)Water absorbs heat from skin oils, which is removed from the body during evaporation.
E)Breaking the bonds holding water molecules together releases energy, which is absorbed by the solutes present in sweat.

Question 24

What are the fundamental building blocks of all matter?

A)atoms
B)compounds
C)ions
D)molecules
E)electrons

Question 25

A molecule is ____.

A)a combination of two or more atoms
B)less stable than its constituent atoms separated
C)always electrically charged
D)a carrier of one or more extra neutrons
E)another term for an atom

Question 26

For an atom to be electrically neutral, it must have the same number of ____.

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

Question 27

Elements are arranged in the ____ according to their ____.

A)periodic table; size
B)pH scale; charge
C)pH scale; mass number
D)periodic table; atomic number
E)orbitals; electronegativity

Question 28

Carbon has several isotopes including ¹²C and ¹⁴C. These isotopes differ in the number of ____.

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

Question 29

A molecule of sodium chloride (NaCl) is ____ because each ion retains its respective charges as they participate in a(n) ____ bond.

A)polar; hydrogen
B)polar; ionic
C)nonpolar; single covalent
D)nonpolar; double covalent
E)polar; covalent

Question 30

An atom of sodium has an atomic number of 11 and a mass number of 23. How many neutrons does it have?

A)11
B)12
C)23
D)34
E)35

Question 31

The measure of an atom's ability to pull electrons away from another atom is called ____.

A)electronegativity
B)polarity
C)charge
D)concentration
E)atomic number

Question 32

Magnesium has 12 protons. How many electrons are in its third energy level?

A)two
B)four
C)six
D)eight
E)ten

Question 33

Which chemical interaction(s) is/are the weakest?

A)hydrogen bonds only
B)ionic bonds only
C)covalent bonds only
D)both hydrogen and covalent bonds
E)both ionic and covalent bonds

Question 34

Sodium (Na) atoms often lose the single electron that is in their outermost shell. How does losing the electron affect sodium's charge?

A)It becomes neutral.
B)It becomes positively charged.
C)It becomes negatively charged.
D)Its electronegativity increases.
E)Its charge is not affected by the loss of an electron.

Question 35

The atomic number is determined by the number of ____ in an atom's nucleus.

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

Question 36

According to the pH scale, which substance is the most acidic?

A)hydrochloric acid, pH=1
B)orange juice, pH=3
C)butter, pH=6
D)pure water, pH=7
E)seawater, pH=8

Question 37

All atoms of a given element contain the same number of ____.

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

Question 38

Calcium has an atomic number of 20. An atom of calcium has ____ electrons in its first energy level and ____ electrons in its second energy level.

A)two; eight
B)four; four
C)six; six
D)eight; two
E)two; ten

Question 39

What is formed when an atom loses or gains an electron?

A)a new element
B)an ion
C)a molecule
D)a bond
E)an isotope

Question 40

Molecular oxygen is composed of two oxygen atoms that share four electrons. How many covalent bonds exist between the two oxygen atoms?

A)none
B)one
C)two
D)four
E)eight

Question 41

Match the terms with their most suitable description.
a.number of protons > number of electrons
b.number of protons in the atomic nucleus
c.polar; easily dissolves in water
d.number of protons < number of electrons
e.number of protons = number of electrons
f.measure of molecular motion
g.number of protons and neutrons in the atomic nucleus
positive charge

Question 42

Match the following terms with the best description.
a.compound
b.polarity
c.electronegativity
d.ion
a charged atom

Question 43

​Imagine that you are pouring some table salt (NaCl) into a glass of water and stirring it until the salt has dissolved. Given this scenario, match the following terms with the best description.​
a.solvent
b.solute
c.solution
the water containing dissolved salt

Question 44

Match the following terms with the best description.
a.compound
b.polarity
c.electronegativity
d.ion
separation of charge into positive and negative regions of a molecule

Question 45

Match the terms with their most suitable description.
a.number of protons > number of electrons
b.number of protons in the atomic nucleus
c.polar; easily dissolves in water
d.number of protons < number of electrons
e.number of protons = number of electrons
f.measure of molecular motion
g.number of protons and neutrons in the atomic nucleus
neutral

Question 46

Match the following terms with the best description.
a.compound
b.polarity
c.electronegativity
d.ion
a type of molecule that has atoms of two or more elements

Question 47

Which statement describes the arrangement or properties of electrons in an atom?

A)Electrons furthest from the nucleus are at the lowest energy level.
B)The first energy level can hold up to eight electrons.
C)Electrons cannot move out of their assigned orbital space.
D)The innermost orbital holds two electrons.
E)At the second energy level, there are two possible orbitals with a total of eight electrons.

Question 48

According to the atomic shell model, the second shell can hold up to ____ electrons.

A)one
B)two
C)four
D)six
E)eight

Question 49

Match the terms with their most suitable description.
a.number of protons > number of electrons
b.number of protons in the atomic nucleus
c.polar; easily dissolves in water
d.number of protons < number of electrons
e.number of protons = number of electrons
f.measure of molecular motion
g.number of protons and neutrons in the atomic nucleus
hydrophilic

Question 50

Hydrophobic molecules are ____ water.

A)attracted to
B)absorbed by
C)repelled by
D)suspended by
E)dissolvable in

Question 51

An atom of which element possesses electrons in only the first and second energy levels? (The number in parentheses indicates the number of electrons in an atom of that element.)

A)sodium (11)
B)magnesium (12)
C)chlorine (17)
D)neon (10)
E)argon (18)

Question 52

Match the terms with their most suitable description.
a.number of protons > number of electrons
b.number of protons in the atomic nucleus
c.polar; easily dissolves in water
d.number of protons < number of electrons
e.number of protons = number of electrons
f.measure of molecular motion
g.number of protons and neutrons in the atomic nucleus
mass number

Question 53

​Imagine that you are pouring some table salt (NaCl) into a glass of water and stirring it until the salt has dissolved. Given this scenario, match the following terms with the best description.​
a.solvent
b.solute
c.solution
the water

Question 54

Match the following terms with the best description.
a.compound
b.polarity
c.electronegativity
d.ion
an atom's ability to pull electrons away from another atom

Question 55

Water is an example of a(n) ____.

A)atom
B)ion
C)compound
D)solution
E)element

Question 56

Due to their instability, free radicals ____.

A)are excellent solvents in biological systems
B)are excellent buffers in biological systems
C)forcibly donate or remove electrons from other molecules
D)can be used as tracers for clinical diagnostic procedures
E)will readily form ionic bonds with polar ions

Question 57

Match the terms with their most suitable description.
a.number of protons > number of electrons
b.number of protons in the atomic nucleus
c.polar; easily dissolves in water
d.number of protons < number of electrons
e.number of protons = number of electrons
f.measure of molecular motion
g.number of protons and neutrons in the atomic nucleus
temperature

Question 58

Match the terms with their most suitable description.
a.number of protons > number of electrons
b.number of protons in the atomic nucleus
c.polar; easily dissolves in water
d.number of protons < number of electrons
e.number of protons = number of electrons
f.measure of molecular motion
g.number of protons and neutrons in the atomic nucleus
atomic number

Question 59

Which chemical interactions is/are classified as true chemical bonds?

A)hydrogen bonds only
B)ionic bonds only
C)covalent bonds only
D)ionic and covalent bonds
E)hydrogen, ionic, and covalent bonds

Question 60

Match the terms with their most suitable description.
a.number of protons > number of electrons
b.number of protons in the atomic nucleus
c.polar; easily dissolves in water
d.number of protons < number of electrons
e.number of protons = number of electrons
f.measure of molecular motion
g.number of protons and neutrons in the atomic nucleus
negative charge

Question 61

Alchemists were medieval scholars and philosophers who were the forerunners of modern-day chemists. Many tried repeatedly to transform lead (atomic number 82) into gold (atomic number 79). Explain why they never succeeded.

Question 62

Match the chemical bond descriptions with the type of bond listed below. Each answer may be used more than once.
a.ionic bond
b.covalent bond
c.hydrogen bond
links ions of opposite charge

Question 63

Explain why atoms such as helium (atomic number 2), neon (atomic number 10), and argon (atomic number 18) do not react with other atoms.

Question 64

Match the chemical bond descriptions with the type of bond listed below. Each answer may be used more than once.
a.ionic bond
b.covalent bond
c.hydrogen bond
forms between atoms with little to no difference in electronegativity

Question 65

What is the difference between strong and weak acids?

Question 66

How can radioisotopes be used as tracers to study biological processes?

Question 67

Match the chemical bond descriptions with the type of bond listed below. Each answer may be used more than once.
a.ionic bond
b.covalent bond
c.hydrogen bond
ions retain their respective charges

Question 68

What makes water an excellent solvent?

Question 69

​Imagine that you are pouring some table salt (NaCl) into a glass of water and stirring it until the salt has dissolved. Given this scenario, match the following terms with the best description.​
a.solvent
b.solute
c.solution
the salt

Question 70

Match the chemical bond descriptions with the type of bond listed below. Each answer may be used more than once.
a.ionic bond
b.covalent bond
c.hydrogen bond
stabilizes the characteristic structures of biological molecules such as DNA and proteins

Question 71

Refer to chemical equation shown here to explain why carbon dioxide dissolved in water acts as a buffer.
H2O + CO2 ←→ H2CO3 ←→ H+ + HCO3

Question 72

A water molecule is polar but has no charge. What makes water molecules polar and how does this polarity contribute to hydrogen bonding?

Question 73

​We all know the saying "It's not the heat, it's the humidity." Why is the cooling effect of sweat ineffective on humid days?

Question 74

Polonium is a rare element with 33 radioisotopes. The most common one, ²¹⁰Po, has 82 protons and 128 neutrons. When ²¹⁰Po decays, it emits an alpha particle, which is a helium nucleus (two protons and two neutrons). ²¹⁰Po decay is tricky to detect because alpha particles do not carry very much energy compared to other forms of radiation. They can be stopped by, for example, a sheet of paper or a few inches of air. That is one reason that authorities failed to discover toxic amounts of ²¹⁰Po in the body of former KGB agent Alexander Litvinenko until after he died suddenly and mysteriously in 2006. What element does an atom of ²¹⁰Po change into after it emits an alpha particle?

Question 75

Match the chemical bond descriptions with the type of bond listed below. Each answer may be used more than once.
a.ionic bond
b.covalent bond
c.hydrogen bond
attraction between a covalently bonded hydrogen atom and another atom taking part in a separate covalent bond

Question 76

What causes ocean acidification? What are some effects of ocean acidification?

Question 77

Draw a shell model of an uncharged nitrogen atom (atomic number 7).

Question 78

Match the chemical bond descriptions with the type of bond listed below. Each answer may be used more than once.
a.ionic bond
b.covalent bond
c.hydrogen bond
sharing of electrons between two atoms

Question 79

Match the chemical bond descriptions with the type of bond listed below. Each answer may be used more than once.
a.ionic bond
b.covalent bond
c.hydrogen bond
single, double, or triple bonds can exist between two atoms