Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biochemistry > Ch. 2 Water (Exam 1) > Flashcards

Ch. 2 Water (Exam 1) Flashcards

Covalent Bonds, Hydrogen Bonds (Non-Covalent), Hydrophobic Effect, Acids, Base, pH

1
Q

How would the electronegativity of a nonpolar covalent bond be described?

A

Not a big difference in EN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How would the electronegativity of a polar covalent bond be described?

A

A significant difference in EN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How polar is an ionic bond, and how would its electronegativity be described?

A

Extremely polar w/ enormous difference in EN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is electronegativity?

A

The measure of an atom’s attraction for electrons it shares w/ another atom

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the periodic table trend for electronegativity?

A

Up and to the right (EN gets stronger)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which type of bonds are most important for biomolecules?

A

Polar bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Why do some molecules have polar bonds but are considered nonpolar overall?

A

Their geometry makes it so that the net vector sum of their dipole moments equals zero

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What shape is water’s molecular geometry?

A

Bent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What shape is water’s electron-pair geometry?

A

Tetrahedral

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Why is liquid water denser than ice?

A

The molecules in liquid water move more closely together, so they are not optimally/maximally hydrogen-bonded (bonds not set in stone)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How do hydrogen bonds affect water’s boiling point?

A

The cohesiveness created by the H-bonds help water molecules resist the need to escape to the gas phase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How do the molecular weight, melting point, and boiling point of non-water hydrides relate to each other?

A

They are all directly proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why does a greater frequency of hydrogen bonds allow for ice to float on water?

A

More frequent, optimal, set-in-stone H-bonds equals less free-floating molecules and less volume by creating hollow regions between the H-bonds that make ice less dense than water

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why is hydrogen bonding important for biomolecules?

A

Hydrogen bonding stabilizes the 3D structures of biomolecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the 3 major types of hydrogen bonds found amongst biomolecules?

A

1) Water to water
2) Water to other polar molecules (w/ carbonyls)
3) Bonds in proteins and nucleic acids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are 2 reasons that oil and water do not mix?

A

1) Nonpolar molecules separate themselves from polar water

2) Water forms H-bonds w/ itself and other polar molecules

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What 2 regions do amphipathic compounds consist of?

A

Hydrophobic and hydrophilic regions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is a micelle?

A

A spherical cluster of amphipathic molecules in water with hydrophobic parts inside the sphere and hydrophilic parts outside with water

19
Q

How can solute molecules dissolve in water if H-bonds between water molecules are so extensive?

A

A stronger interaction than hydrogen bonding exists between solute and water

20
Q

What are 2 compounds that can dissolve fairly easy in water?

A

Ionic and polar covalent compounds

21
Q

How do ionic compounds dissolve in water?

A

Cations interact with oxygen, and anions interact with hydrogens in a process called hydration

22
Q

How do uncharged polar molecules interact w/ water molecules?

A

Hydrogen bonding

23
Q

What does pure water produce when it dissociates?

A

Equal amounts of protons and hydroxide ions

24
Q

What does an acid increase in a solution?

A

Proton concentration

25
Q

What does a base decrease in a solution?

A

Proton concentration

26
Q

What is the dissociative difference between weak and strong acids?

A

Weak acids partially dissociate in water while strong acids completely dissociate

27
Q

What is the dissociative difference between weak and strong bases?

A

The same thing as weak and strong acids (weak partially dissociates in water while strong fully dissociates)

28
Q

Neutral solutions contain equal concentrations of what?

A

Acids and bases

29
Q

What is the physiological pH range?

A

2-8

30
Q

What is the formula for calculating pH based on proton concentration?

A

pH = -log[H+]

31
Q

What does pKa express?

A

The strength of a weak acid

32
Q

What does a lower pKa mean for an acid?

A

Lower pKa = stronger acid

33
Q

What formula determines pKa?

A

pKa = -log Ka

34
Q

What is the acid dissociation constant?

A

Ka

35
Q

What does a titration curve measure?

A

pH and acid concentration

36
Q

What is the buffering region, and what does it correspond to?

A

Area on a titration curve where little pH change occurs, and it corresponds to pKa value

37
Q

What is a buffer?

A

A solution that resists change in pH when acids or bases are added

38
Q

How are buffers made?

A

Combination of a weak acid and conjugate base

39
Q

When does the best buffering occur?

A

1 pH unit above and below pKa

40
Q

What relationship does the Henderson-Hasselback equation establish when selecting a buffer?

A

The relationship between pH and pKa

41
Q

What is the formula for the Henderson-Hasselback equation?

A

pH = pKa + log([A-]/[HA])

42
Q

What is special about each of the ionizable groups of weak acids?

A

Each ionizable group has its own pKa

43
Q

How are the protons of a weak acid released on a titration curve?

A

Stepwise

Biochemistry (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions