WATER

Question 1

Water has a substantially higher what properties

Answer 1

boiling point, melting point, heat of vaporization, and surface tension

Question 2

The properties of water suggest that

Answer 2

intermolecular forces of attraction between H2O molecules are high.

Question 3

water’s maximum density is found in the liquid (not the solid) because?

Answer 3

water has an unusually high dielectric constant

Question 4

is the crucial fact to understanding its properties of water

Answer 4

the unrivaled ability to form
hydrogen bonds

Question 5

Covalent bond length of water molecules =

Answer 5

0.095 nm

Question 6

van der Waals radius of hydrogen =

Answer 6

0.12 nm

Question 7

van der Waals radius of oxygen =

Answer 7

0.14 nm

Question 8

bond degree of water

Answer 8

104.3

Question 9

this property renders the
water molecule distinctly polar.

Answer 9

Bent structure

Question 10

What allows this substance to have anomalously high boiling point, melting point, heat of vaporization, and surface tension.
Source of the strong intermolecular attractions

Answer 10

The potential to form four H bonds per water molecule

Question 11

power of H bonds between neighboring molecules

Answer 11

23 kJ/mol each

Question 12

power of H-O covalent bonds

Answer 12

420 kJ/mol

Question 13

water is an excellent solvent for ionic sub-stances because?

Answer 13

highly polar nature

Question 14

sodium chloride is dissolved because dipolar water molecules participate in strong electrostatic interactions with the Na+ and Cl- ions, leading to the formation of

Answer 14

hydration shells

Question 15

average lifetime of H bonds between water molecules is about

Answer 15

10 psec

Question 16

Water’s ability to surround ions in di-pole interactions and diminish their attraction for each other is a measure of its

Answer 16

dielectric constant

Question 17

formula for finding the force in relation to the dielectric constant

Answer 17

F = e1e2/Dr 2

Question 18

Dielectric constant of liquid water

Answer 18

around 78.4

Question 19

Water Forms H Bonds with

Answer 19

Polar Solutes

Question 20

The behavior of water toward nonpolar solutes

Answer 20

Hydrophobic Interactions

Question 21

H-bonded water network rearranges toward formation of a local cage-like structure surrounding each solute molecule in hydrophobic interactions

Answer 21

clathrate

Question 22

allows the water molecules to retain their H-bonding possibilities because no H-bond donor or acceptor of the H2O is directed toward the caged solute

Answer 22

Straddling

Question 23

clathrate formation is accompanied by s

Answer 23

significant ordering of structure or negative entropy.

Question 24

Compounds containing both strongly polar and strongly nonpolar groups are called

Answer 24

Amphiphilic Molecules

Question 25

Amphiphilic Molecules are also known as

Answer 25

amphipathic molecules

Question 26

Such clusters of amphipathic molecules are termed

Answer 26

micelles

Question 27

This influence of the solute on water is reflected in a set of characteristic changes in behavior termed

Answer 27

Colligative Properties

Question 28

The water molecules are moving from a region of _________ to a region of_________

Answer 28

higher effective concentration ; lower effective concentration

Question 29

to minimize the osmotic pressure created by the contents of their cytosol, cells tend to store substances such as amino acids and sugars in

Answer 29

polymeric form.

Question 30

Used by plant and bacterial cell in order to resist osmotic pressures

Answer 30

rigid cell walls

Question 31

Present in animal cell that is the reason why no net osmotic gradient is present

Answer 31

extracellular fluid with relative osmotic pressure

Question 32

Water ionizes because the _________ strips the electron from one of its hydrogen atoms, leaving the proton to dissociate

Answer 32

larger, strongly electronegative oxygen atom

Question 33

The amount of H3O+ or OH- in 1 L (liter) of pure water at 25°C is

Answer 33

1 x 10^-7 mol;

Question 34

the molar concentration of H2O in pure water is

Answer 34

55.5 M

Question 35

molecular weight of H2O

Answer 35

18

Question 36

a Danish biochemist, devised the pH scale by defining pH as the negative logarithm of the hydrogen ion concentration

Answer 36

Søren Sørensen

Question 37

pH FORMULA

Answer 37

pH = -log10 [H+]

Question 38

Substances that are almost completely dissociated to form ions in solution are called

Answer 38

strong electrolytes.

Question 39

describes substances capable of generating ions in solution and thereby causing an increase in the electrical conductivity of the solution.

Answer 39

electrolyte

Question 40

Substances with only a slight tendency to dissociate to form ions in solution are called

Answer 40

weak electrolytes

Question 41

Describes the Dissociation of a Weak Acid In the Presence of Its Conjugate Base

Answer 41

Henderson–Hasselbalch Equation

Question 42

is the analytical method used to determine the amount of acid in a solution.

Answer 42

Titration

Question 43

are solutions that tend to resist changes in their pH as acid or base is added.

Answer 43

Buffers

Question 44

Typically, a buffer system is composed of a

Answer 44

weak acid and its conjugate base

Question 45

The pH of the extracellular fluid that bathes the cells and tissues of animals is maintained by the

Answer 45

bicarbonate/carbonic acid (HCO3􀀂/H2CO3) system.

Question 46

Two buffer systems act to maintain intracellular pH

Answer 46

the phosphate (HPO42􀀂/H2PO4􀀂) system and the histidine system.