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Flashcards in Chapter 2 Deck (19)
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1
Q

…: the distance of closest approach between two nonbonded atoms

A

van der Waals distance

2
Q

In ice, each water molecule interacts … with … other water molecules

A

tetrahedrally; four

3
Q

ice is less dense than water bc H2O … upon freezing, giving it an open structure

A

expands

4
Q

liquid water consists of rapidly fluctuating, …. (clusters) of hydrogen bonded H2O molecules

A

three dimensional networks

5
Q

the energy of association of two electric charges, q1 and q2 that are immersed in a medium of dielectric constant D and separated by the distance r, is given by Coulomb’s law:

A
U = (kq1q2)/Dr
k = 9.0 x 10^9 J*m*C^-2 (proportionality constant0
6
Q

in general, the energy of association of two charged groups (the energy required to completely separate them in the medium of interest) is less than the energy of a … but greater than the energy of a …

A

covalent bond; hydrogen bond

7
Q

the tendency of water to minimize its contacts with hydrophobic molecules is termed the

A

hydrophobic effect

8
Q

the extensive H bonding network of liquid H2O is disturbed when a nonpolar group intrudes. A nonpolar group can neither accept/donate H bonds so water molecules at the surface of the cavity cannot H bond to other molecules in their usual fashion. They then must orient themselves to form a … enclosing the cavity, decreasing … as they give up some of their rotational and translational freedom

A

hydrogen-bonded network; entropy

9
Q

the aggregation of the nonpolar groups minimizes the … of the cavity and maximizes the … of the entire system

A

surface area; entropy

10
Q

Despite the temptation to attribute some mutual attraction to a collection of nonpolar groups excluded from water, their exclusion is largely a function of the …. of the surrounding water molecules, not some “hydrophobic force”

A

entropy

11
Q

…. properties: physical properties that depend on the concentration of dissolved substance rather than on their chemical features

A

colligative

12
Q

the … of a solution is the pressure that must be applied to the solution to equalize the flow of water across the membrane in both directions

A

osmotic pressure

13
Q

during dialysis, solutes diffuse across a … from regions of higher concentration to regions of lower concentration

A

semipermeable membrane

14
Q

… is also responsible for the observation that acid base reactions are among the fastest reactions that take place in aqueous solution. this process is the spontaneous movement of H+ ions in solution

A

proton jumping

15
Q

K = …

A

([H+][A-])/[HA][H2O]

16
Q

since strong acids rapidly transfer all their protons to H2O, the strongest acid that can stably exist in aqueous solutions is … likewise, there can be no stronger base in aqueous solutions than …

A

H3O+; OH-

17
Q

the pH at the midpoint of each titration is numerically equivalent to the … of its corresponding acid; at this point [HA] = …

A

pK; [A-]

18
Q

When [HA] is approximately = [A-], the pH of the solution is relatively … to the addition of strong base/acid –> buffer

A

insensitive

19
Q

the buffering capacity of these weak acids is maximal when … it is helpful to remember that a weak acid is in its useful buffer range within … of its pK

A

pH = pK; one pH unit