Deck 2: Life, Chemistry, and Water

Question 1

An oxygen atom has ____ surrounding a nucleus composed of ____.

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

Answer 1

B

Question 2

Ice floats in liquid water because there are, on average, fewer hydrogen bonds between molecules in ice than water, resulting in a lower density.

Answer 2

False

Question 3

The four elements that make up more than 96.5% of the weight of living organisms are oxygen, carbon, hydrogen, and calcium.

Answer 3

False

Question 4

Radioactive ____ is commonly used to treat patients with dangerously overactive thyroid glands.

A) carbon
B) radium
C) iodine
D) thallium
E) cobalt

Question 5

A trace element is one found in specific organisms in ____ quantities and is ____ for normal biological functions.

A) moderate; unnecessary
B) moderate; vital
C) small; unnecessary
D) large; unnecessary
E) small; vital

Question 6

The smallest unit that retains the chemical and physical properties of an element is a(n) ____.

A) proton
B) compound
C) molecule
D) neutron
E) atom

Question 7

Atoms with atomic numbers between lithium and neon have two energy levels.

Question 8

Prolonged iodine deficiency causes ____, a condition in which the thyroid gland enlarges so much that the front of the neck swells significantly.

A) gout
B) cancer
C) a goiter
D) anemia
E) granuloma

Question 9

Figure 2.1
Answer the question using the accompanying figure. The mass number of the atom depicted in the figure is ____.

A) 4
B) 6
C) 8
D) 12
E) 18

Question 10

Carbon dioxide is an element.

Question 11

In the representation of hydrogen gas, H-H, the dash represents two electrons being shared equally.

Question 12

The substance H₂O is considered to be ____.

A) both a molecule and a compound
B) a compound but not a molecule
C) neither a molecule nor a compound
D) a molecule but not a compound
E) both a molecule and an ion

Question 13

Acid precipitation can have a pH as low as 3.

Question 14

Four elements, including ____, make up more than 96.5% of the mass of most living organisms.

A) sodium
B) potassium
C) phosphorus
D) nitrogen
E) calcium

Question 15

Proteins in thermophiles must be stabilized by van der Waals forces, because hydrogen bonds cannot be maintained at high temperatures.

Question 16

Buffers can increase the pH of a solution when acids are added.

Question 17

The substance O₂is considered to be ____.

A) both a molecule and a compound
B) a compound but not a molecule
C) neither a molecule nor a compound
D) a molecule but not a compound
E) both a molecule and an ion

Question 18

Diluted acetic acid, CH₃COOH, is commonly called vinegar. How many atoms of hydrogen are present in one molecule of acetic acid?

A) one
B) two
C) three
D) four
E) five

Question 19

The polarity of water allows it to create a hydration layer that prevents salt from coming back out of solution after it has been dissolved.

Question 20

Hydrogen, atomic number 1, has three isotopes,¹H,²H,³H.¹H is comprised of one proton, one neutron, and one electron.

Question 21

Which element is likely to be chemically unreactive?

A) chlorine (seven valence electrons)
B) calcium (two valence electrons)
C) argon (eight valence electrons)
D) carbon (four valence electrons)
E) potassium (one valence electron)

Question 22

Figure 2.2
Answer the question using the accompanying figure. All of the orbitals shown in the neon atom are completely filled with electrons. How many electrons does this neon atom have?

A) five
B) six
C) eight
D) 10
E) 16

Question 23

Metallic ions such as Ca²⁺, Na⁺, and Fe³⁺readily form ____.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 24

Isotopes of the same element differ from each other in the number of ____.

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

Question 25

A carbon atom with six protons, seven neutrons, and six electrons has a mass number of ____.

A) 6
B) 7
C) 12
D) 13
E) 19

Question 26

Which of the three atomic particles are charged?

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

Question 27

The chemical linkages that exert an attractive force over the greatest distance are ____.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 28

Sodium has one valence electron in its third energy level. To reach a stable energy configuration, sodium will tend to____.

A) take up an electron from another atom
B) move its valence electron to the second energy shell
C) give up an electron to another atom
D) share its valence electron with another atom
E) move an electron from the second energy level to the valence shell

Question 29

Answer the question using the accompanying figure. The atomic number of the atom depicted in the figure is ____.

A) 4
B) 6
C) 8
D) 12
E) 18

Question 30

Which element is most likely to accept an electron from another atom?

A) chlorine (seven valence electrons)
B) calcium (two valence electrons)
C) neon (eight valence electrons)
D) carbon (four valence electrons)
E) potassium (one valence electron)

Question 31

When the isotope¹⁴C undergoes radioactive decay, a neutron splits into an electron and a proton, with ejection of the electron. This decay produces an atom of ____.

A) iron
B) carbon
C) hydrogen
D) oxygen
E) nitrogen

Question 32

Answer the question using the accompanying figure. The atom depicted in this figure can form ____ covalent bonds with another atom.

A) 0
B) 2
C) 4
D) 3
E) 6

Question 33

Figure 2.2
Answer the question using the accompanying figure. The electrons at the lowest energy level in the neon atom depicted are found in which orbital?

A) 1 s
B) 2 s
C) 2 p x
D) 2 p y
E) 2 p z

Question 34

The attraction between Na⁺cations and Cl^-anions form ____ that hold the ions together in the compound NaCl.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 35

An orbital describes the ____ of an electron.

A) exact location
B) exact path
C) most frequent locations
D) charge
E) chemical bonds

Question 36

14C is heavier than¹²C because it has ____.

A) two more electrons than¹²C
B) two more neutrons than¹²C
C) two more protons than¹²C
D) two more protons and two more electrons than¹²C
E) one more proton and one more neutron than¹²C

Question 37

Electronegativity is the tendency of an atom to attract ____ to itself in a chemical bond.

A) neutrons
B) protons
C) electrons
D) delta forces
E) polar associations

Question 38

Chemical bonds that are formed when one atom with a partial positive charge (created from unequal sharing of electrons) is electrically attracted to another atom with a partial negative charge (also created from unequal sharing of electrons) are called ____.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 39

Which element is most likely to share electrons with other atoms in joint orbitals?

A) chlorine (seven valence electrons)
B) calcium (two valence electrons)
C) argon (eight valence electrons)
D) carbon (four valence electrons)
E) potassium (one valence electron)

Question 40

The chemical bonds that are formed when atoms share electrons equally are called ____.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 41

Which substance would have the most difficulty entering a water lattice?

A) table salt (NaCl)
B) a nonpolar molecule
C) a sodium ion
D) a proton (H⁺)
E) an electron

Question 42

In the presence of water, nonpolar associations form between molecules or regions of molecules that are ____.

A) partially charged
B) hydrophobic and hydrophilic
C) hydrophobic
D) fully charged
E) hydrophilic

Question 43

In a molecule of methane, CH₄, each hydrogen atom shares an orbital with the carbon atom. The total number of shared electrons in CH₄is ____.

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

Question 44

A polar covalent bond would be most likely to form between ____.

A) atoms with different electronegativities
B) cations and anions
C) atoms with partial positive and partial negative charges
D) atoms with filled valence shells
E) atoms of the same element

Question 45

A mixture of vegetable oil and water will separate into layers because oil is ____ and forms ____.

A) hydrophobic; nonpolar associations
B) hydrophilic; nonpolar associations
C) hydrophilic; polar associations
D) hydrophobic; polar associations
E) hydrophobic; ionic associations

Question 46

Which type of chemical linkage is the weakest?

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 47

The hydrogen-bond lattice causes water to have an unusually ____ specific heat, an unusually ____ heat of vaporization, and an unusually ____ density in solid form.

A) high; high; high
B) low; low; low
C) high; low; high
D) high; high; low
E) low; low; high

Question 48

Water has an important stabilizing effect on temperature in living organisms and their environments because as water absorbs heat, much of the energy is used to ____ instead of raising the temperature.

A) create hydrogen bonds
B) create covalent bonds
C) break surface tension
D) break hydrogen bonds
E) create hydration layers

Question 49

Figure 2.4
The water strider shown in the figure above is able to stand on water because of the ____ of water.

A) covalent bonds
B) surface tension
C) van der Waals forces
D) density
E) hydration layer

Question 50

Water has an unusually high boiling point for its molecular weight because water molecules ____.

A) are very dense
B) get much heavier as they are heated
C) are held to each other by hydrogen bonds
D) are held together by covalent bonds
E) form hydration layers

Question 51

A molecule of water in the middle of a chunk of ice will usually have ____ hydrogen bonds with other water molecules.

A) two
B) three
C) 3.4
D) four
E) six

Question 52

When water molecules exposed to the air form hydrogen bonds between adjacent water molecules below and beside them, molecules in the upper layer become more resistant to separating from those underneath. This property of water is known as ____.

A) cohesion
B) adhesion
C) a hydration layer
D) a water lattice
E) surface tension

Question 53

Figure 2.5
The water lattice illustrated in the figure above forms as a result of ____ between water molecules.

A) covalent bonds
B) hydrogen bonds
C) nonpolar interactions
D) ionic bonds
E) van der Walls forces

Question 54

In contrast to ionic bonds, covalent bonds ____.

A) hold atoms together
B) have distinct, three-dimensional forms
C) transfer electrons from one atom to another
D) are rarely broken
E) are transient

Question 55

Multiple hydrogen bonds together stabilize proteins into a spiral structure called a ____.

A) water lattice
B) alpha helix
C) chemical groups
D) delta minus
E) delta plus

Question 56

The formation and breaking of bonds between atoms requires ____.

A) a chemical reaction
B) van der Walls forces
C) partial charges
D) an empty valence shell
E) an enzyme

Question 57

Molecules such as H-H and O=O are held together by ____.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 58

Figure 2.3
Answer the question using the accompanying figure. The molecule shown is held together by ____.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 59

How many calories, as defined in chemistry, are in one calorie, which is the unit used to quantify the amount of energy in the food we eat?

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

Question 60

Geckos are able to cling to vertical walls due to ____.

A) polar covalent bonds
B) van der Waals forces
C) ionic bonds
D) hydrogen bonds
E) nonpolar covalent bonds

Question 61

When added to water at neutral pH (7.0), an acid will ____.

A) act as a proton donor, raising the pH of the solution
B) act as a proton acceptor, raising the pH of the solution
C) act as a proton donor, lowering the pH of the solution
D) act as a proton acceptor, lowering the pH of the solution
E) do nothing since the aqueous solution is neutral

Question 62

Solution A has a pH of 6 and solution B has a pH of 8. Therefore, ____.

A) A has 10 times greater H⁺concentration than B.
B) B has 10 times greater H⁺concentration than A.
C) A has 100 times greater H⁺concentration than B.
D) B has 100 times greater H⁺concentration than A.
E) A has 1,000 times greater H⁺concentration than B.

Question 63

Biological membranes are held together mainly by ____.

A) hydrogen bonds between lipid molecules
B) hydration layers over lipid molecules
C) exclusion of the nonpolar regions of lipids by water
D) hydrogen bonds between water molecules
E) surface tension at the interface between layers of water molecules

Question 64

Pure water has a pH of 7.0, therefore, ____.

A) [H⁺]^-]
B) [H⁺] = [OH^-]
C) [H⁺] = 0
D) [OH^-] = 0
E) [H⁺]>[OH^-]

Question 65

The most common isotope of carbon has an atomic number of 6 and a mass number of 12, while the most common isotope of oxygen has an atomic number of 8 and a mass number of 16. A molecule of CO₂made up of these common isotopes has a molecular weight of ____.

A) 28
B) 44
C) 56
D) 14
E) 22

Question 66

High levels of carbon dioxide in the atmosphere are causing ____.

A) the pH of the ocean to increase
B) the pH of the ocean to decrease
C) the natural buffers in the ocean to die
D) increased calcification of the coral reefs
E) increased biodiversity in coral reefs

Question 67

Avogadro's number represents the ____.

A) number of grams in a mole of substance
B) number of moles in a gram of substance
C) number of atoms in one gram of substance
D) atomic weight of an atom divided by the weight of an atom of that element
E) weight of an atom of an element divided by the atomic weight of that element

Question 68

Seawater typically is ____.

A) highly basic
B) neutral
C) somewhat basic
D) somewhat acidic
E) highly basic

Question 69

A pH of 6 is ____ times more ____ than a pH of 2.

A) 3; acidic
B) 4; acidic
C) 3; basic
D) 10,000; basic
E) 40; basic

Question 70

A ____ is formed when a ____ is dissolved in a ____.

A) solution; solute; solvent
B) solute; solvent; solution
C) solution; solvent; solute
D) solvent; solution; solute
E) solvent; solute; solution

Question 71

When added to water, a base will act as a(n) ____ and cause the pH of the solution to ____.

A) proton acceptor; rise
B) proton donor; rise
C) proton acceptor; fall
D) proton donor; fall
E) acid; fall

Question 72

Ethanol, the alcohol found in wine and beer, has the molecular formula CH₃CH₂OH. What is the molecular weight of ethanol if the atomic weight of C=12, H=1, and O=16?

A) 29 g/mol
B) 30 g/mol
C) 34 g/mol
D) 45 g/mol
E) 46 g/mol

Question 73

When salt dissolves in water, the water molecules form ____ around the Na⁺and Cl^-ions.

A) covalent bonds
B) hydration layers
C) nonpolar interactions
D) membranes
E) ionic bonds

Question 74

Lemon juice has a pH of 2.0, therefore, ____.

A) [H⁺]^-]
B) [H⁺] = [OH^-]
C) [H⁺] = 0
D) [OH^-] = 0
E) [H⁺]>[OH^-]

Question 75

Most pH buffers are ____.

A) strong acids
B) weak acids or weak bases
C) weak acids
D) strong bases
E) strong acids or strong bases

Question 76

Consider the equilibrium established in the carbonic acid-bicarbonate buffer system, which maintains pH balance in mammalian blood:

During hypoventilation, breathing rate decreases, and therefore elimination of CO2 during exhalation decreases. How is optimal blood pH maintained when acid levels increase in our blood from hypoventilating?

A) Excess H+ from the acid reacts with H₂CO₃to decrease pH level.
B) Excess H+ from the acid reacts with H₂CO₃to increase pH level.
C) Excess H+ from the acid reacts with H₂CO₃to maintain pH level.
D) Excess H+ from the acid reacts with HCO3- to increase pH level.
E) Excess H+ from the acid reacts with HCO3- to maintain pH level.

Question 77

When sugar dissolves in water, water is acting as a ____ and the sugar molecules are acting as ____.

A) solution; solvents
B) solute; solutions
C) solvent; solutes
D) solute; solvents
E) solvent; solutions

Question 78

Without ____, living organisms would often experience major changes in pH in their cells.

A) buffers
B) acids
C) surface tension
D) nonpolar bonds
E) bases

Question 79

Water has a molecular weight of 18 g per mole, and glucose has a molecular weight of 180 g per mole. Which masses of water and glucose would have an approximately equal number of molecules?

A) 1 g of water and 180 g of glucose
B) 90 g of water and 9 g of glucose
C) 180 g of water and 1 g of glucose
D) 9 g of water and 90 g of glucose
E) 90 g of water and 90 g of glucose

Question 80

In water, NaOH almost completely separates into Na⁺and OH^-ions. Thus, NaOH is _____.

A) a strong acid
B) a strong base
C) a weak acid
D) a weak base
E) neutral