Chem 221 - Biochemistry for Science Majors » Fall 2021 » L2 Water Part 1 of 2
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Question #1
A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?
A.
It should dissolve in a nonpolar solvent
B.
It won't form hydrogen bonds with water
C.
It should dissolve in water
D.
It is hydrophobic
E.
It lacks a hydrogen, so it acts as an acid
Question #2
Which one of the following functional groups does not participate in hydrogen bonding?
A.
Hydroxyl
B.
Amino
C.
Methyl
D.
Amido (amide)
E.
Carboxyl
Question #3
Which of the following alcohols would be most soluble in water?
A.
methanol
B.
ethanol
C.
butanol
D.
octanol
Question #4
With respect to hydrogen bonds,
A.
they are stronger than covalent bonds
B.
water does not have to be involved
C.
they are stronger than disulfide bonds
D.
they are what make peptide bonds
Question #5
A solution with pH = 5 is __________ than a solution with pH = 7.
A.
2 times more basic
B.
100 times more acidic
C.
10 times more acidic
D.
10 times more basic
Question #6
The lone pair electrons on oxygen in a H2O molecule
A.
form covalent bonds in ice
B.
carry a partial negative charge
C.
carry a partial positive charge
D.
are not important for the properties of water
Question #7
The dissociation constant of H2O at 25° C is
A.
10^-7 M
B.
10^14 M
C.
10^7 M
D.
10^-14 M
Question #8
Weak acids generally have pKa
A.
values greater than 2
B.
been seldom found in living systems
C.
values less than 1
D.
that cannot be used to buffer
Question #9
The three-dimensional structure of macromolecules is formed and maintained primarily through non-covalent interactions. Which one of the following is not considered a non-covalent interaction?
A.
Hydrophobic interactions
B.
Ionic interactions
C.
Hydrogen bonds
D.
van der Waals interactions
E.
Carbon-carbon bonds
Question #10
Osmosis is movement of a:
A.
charged solute molecule (ion) across a membrane
B.
polar solute molecule across a membrane
C.
gas molecule across a membrane
D.
water molecule across a membrane
E.
nonpolar solute molecule across a membrane
Question #11
A hydronium ion:
A.
has the structure H3O+
B.
is the usual form of one of the dissociation products of water in solution
C.
is a hydrated proton
D.
is a hydrated hydrogen ion
E.
All of the above are true
Question #12
A hydride ion:
A.
has the structure H-, is the anion of hydrogen, and contains one protons and two electrons
B.
contains two protons and two electrons and has the structure H-
C.
contains two protons and two electrons and is the anion of hydrogen
Question #13
The aqueous solution with the lowest pH is:
A.
10–12 M NaOH
B.
1 M acetic acid (pKa = 4.86)
C.
1 M HCl
D.
1 M formic acid (pKa = 3.75)
E.
2 M HCl
Question #14
Salt dissolves well in water as water molecules
A.
surround the ions because of their charge but do not form hydrogen bonds
B.
make nonpolar covalent bonds with the positively charged ions only
C.
share electrons with the ions to make polar covalent bonds
D.
form hydrogen bonds with the positively and negatively charged ions
Question #15
If an ion for which the cell membrane does not have a transport protein is injected into the blood in significant amounts, which of the following would occur?
A.
The blood cells would shrivel due to osmotic movement of water out of the cell
B.
The blood cells would swell and eventually burst
C.
Blood proteins would diffuse into the cells to compensate
D.
The speed of blood flow through the vessels would increase
E.
The volume of the blood would decrease
Question #16
The pKa of acid A is 4.5 and the pKa of acid B is 7.2. Acid B is a stronger acid than A.
A.
TRUE
B.
FALSE
Question #17
For a weak acid, low pKa means high dissociation.
A.
FALSE
B.
TRUE
Question #18
When crystalline substances (salts) dissolve in water, they acquire greater freedom of motion, which decreases the entropy of the system.
A.
TRUE
B.
FALSE
Question #19
Adding an acid to pure water decreases the [OH-]
A.
TRUE
B.
FALSE
Question #20
Adding an acid to pure water decreases the [H3O+]
A.
TRUE
B.
FALSE
Question #21
If NaOH(s) is dissolved in water, increasing the [OH-], the [H+] must decrease.
A.
FALSE
B.
TRUE
Question #22
In any aqueous solution at 25 °C, no matter what it contains, the product of [H+] and [OH-] must always equal 1.0 x 10-7.
A.
TRUE
B.
FALSE
Question #23
Hydrogen ions (H+) formed in the dissociation of water are immediately hydrated to hydronium ions (H3O+).
A.
TRUE
B.
FALSE
Question #24
In a phospholipid bilayer, the hydrophilic heads are exposed to outside water molecules while the hydrophobic tails inside the bilayer.
A.
FALSE
B.
TRUE
Question #25
Each acid has a characteristic tendency to lose its proton in an aqueous solution. The weaker the acid, the greater its tendency to lose its proton.
A.
FALSE
B.
TRUE
Question #26
A molecule change its ionization state by gaining or losing a proton (H+).
A.
TRUE
B.
FALSE
Question #27
Acetic acid is a strong acid.
A.
TRUE
B.
FALSE
Question #28
Sodium hydroxide is a strong base.
A.
FALSE
B.
TRUE
Question #29
Acetic acid has has two pKas.
A.
FALSE
B.
TRUE
Question #30
Many biochemical molecules are either weak acids or weak bases.
A.
FALSE
B.
TRUE
Question #31
When you add an acid or a base to water, the product of [H+] and [OH-] changes.
A.
TRUE
B.
FALSE
Question #32
If the pKa of acid A is 2 and the pKa of acid B is 4, that means that
A.
A is 200 stronger than B
B.
A is 100 weaker than B
C.
A is 100 stronger than B
Question #33
Sulfuric acid is a weak acid.
A.
TRUE
B.
FALSE
Question #34
The degree of ionization of water to hydrogen ions (H+) and hydroxide ions (OH-) is considered
A.
small
B.
large
Question #35
The ionization of water is irreversible
A.
TRUE
B.
FALSE
Question #36
Of the non covalent interactions, the strongest is
A.
hydrogen bonding
B.
hydrophobic interactions
C.
ionic bonding
Question #37
Of the non covalent interactions, the weakest is
A.
ionic bonds
B.
hydrophobic interactions
C.
hydrogen bonding
Question #38
A.
TRUE
B.
FALSE
Question #39
Water has a
A.
it varies
B.
trigonal planar geometry
C.
tetrahedral geometry
D.
linear geometry
Question #40
The total number of hydrogen bonds of a water molecule is
A.
3
B.
2
C.
2
D.
4
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