L2 Water Part 1 of 2

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Question #1

The total number of hydrogen bonds of a water molecule is

A 2

B 4

C 3

D 2

Question #2

Water has a

A trigonal planar geometry

B tetrahedral geometry

C linear geometry

D it varies

Question #3

Intramolecular forces are weaker than intermolecular forces

A FALSE

B TRUE

Question #4

Of the non covalent interactions, the weakest is

A hydrogen bonding

B hydrophobic interactions

C ionic bonds

Question #5

Of the non covalent interactions, the strongest is

A hydrophobic interactions

B hydrogen bonding

C ionic bonding

Question #6

The ionization of water is irreversible

A TRUE

B FALSE

Question #7

The degree of ionization of water to hydrogen ions (H+) and hydroxide ions (OH-) is considered

A large

B small

Question #8

Sulfuric acid is a weak acid.

A FALSE

B TRUE

Question #9

If the pKa of acid A is 2 and the pKa of acid B is 4, that means that

A A is 100 stronger than B

B A is 200 stronger than B

C A is 100 weaker than B

Question #10

When you add an acid or a base to water, the product of [H+] and [OH-] changes.

A FALSE

B TRUE

Question #11

Many biochemical molecules are either weak acids or weak bases.

A FALSE

B TRUE

Question #12

Acetic acid has has two pKas.

A TRUE

B FALSE

Question #13

Sodium hydroxide is a strong base.

A FALSE

B TRUE

Question #14

Acetic acid is a strong acid.

A FALSE

B TRUE

Question #15

A molecule change its ionization state by gaining or losing a proton (H+).

A FALSE

B TRUE

Question #16

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 TRUE

B FALSE

Question #17

In a phospholipid bilayer, the hydrophilic heads are exposed to outside water molecules while the hydrophobic tails inside the bilayer.

A TRUE

B FALSE

Question #18

Hydrogen ions (H+) formed in the dissociation of water are immediately hydrated to hydronium ions (H3O+).

A TRUE

B FALSE

Question #19

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 FALSE

B TRUE

Question #20

If NaOH(s) is dissolved in water, increasing the [OH-], the [H+] must decrease.

A TRUE

B FALSE

Question #21

Adding an acid to pure water decreases the [H3O+]

A TRUE

B FALSE

Question #22

Adding an acid to pure water decreases the [OH-]

A FALSE

B TRUE

Question #23

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 #24

For a weak acid, low pKa means high dissociation.

A TRUE

B FALSE

Question #25

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 FALSE

B TRUE

Question #26

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 Blood proteins would diffuse into the cells to compensate

B The speed of blood flow through the vessels would increase

C The blood cells would shrivel due to osmotic movement of water out of the cell

D The blood cells would swell and eventually burst

E The volume of the blood would decrease

Question #27

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 #28

The aqueous solution with the lowest pH is:

A 1 M acetic acid (pKa = 4.86)

B 1 M HCl

C 10–12 M NaOH

D 1 M formic acid (pKa = 3.75)

E 2 M HCl

Question #29

A hydride ion:

A contains two protons and two electrons and is the anion of hydrogen

B has the structure H-, is the anion of hydrogen, and contains one protons and two electrons

C contains two protons and two electrons and has the structure H-

Question #30

A hydronium ion:

A has the structure H3O+

B is a hydrated hydrogen ion

C is a hydrated proton

D is the usual form of one of the dissociation products of water in solution

E All of the above are true

Question #31

Osmosis is movement of a:

A gas molecule across a membrane

B polar solute molecule across a membrane

C charged solute molecule (ion) across a membrane

D water molecule across a membrane

E nonpolar solute molecule across a membrane

Question #32

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 Ionic interactions

B Hydrogen bonds

C van der Waals interactions

D Carbon-carbon bonds

E Hydrophobic interactions

Question #33

Weak acids generally have pKa

A been seldom found in living systems

B that cannot be used to buffer

C values less than 1

D values greater than 2

Question #34

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 #35

The lone pair electrons on oxygen in a H2O molecule

A carry a partial negative charge

B are not important for the properties of water

C form covalent bonds in ice

D carry a partial positive charge

Question #36

A solution with pH = 5 is __________ than a solution with pH = 7.

A 10 times more acidic

B 10 times more basic

C 2 times more basic

D 100 times more acidic

Question #37

With respect to hydrogen bonds,

A they are stronger than covalent bonds

B they are stronger than disulfide bonds

C they are what make peptide bonds

D water does not have to be involved

Question #38

Which of the following alcohols would be most soluble in water?

A butanol

B methanol

C octanol

D ethanol

Question #39

Which one of the following functional groups does not participate in hydrogen bonding?

A Carboxyl

B Methyl

C Amino

D Hydroxyl

E Amido (amide)

Question #40

A compound contains hydroxyl groups as its predominant functional group. Which of the following statements is true concerning this compound?

A It is hydrophobic

B It should dissolve in a nonpolar solvent

C It lacks a hydrogen, so it acts as an acid

D It won’t form hydrogen bonds with water

E It should dissolve in water

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L2 Water Part 1 of 2

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