Ch 1 and 2 questions

Question 1

The \_\_\_\_\_\_\_\_ describes the tendency for hydrophobic molecules to aggregate because of the exclusion of water with the consequent increase of entropy of the solvent.
hypertonic effect 
 hydrophilic effect 
 hypotonic effect 
 hydrophobic effect

Answer 1

hydrophobic effect

Question 2

Micelles, formed by detergents in water, have ________.
Hydrophobic interiors and hydrophilic exteriors
Hydrophilic interiors and hydrophobic exteriors
Hydrophilic interiors and exteriors
Hydrophobic interiors and exteriors

Answer 2

Hydrophobic interiors and hydrophilic exteriors

Question 3

Water molecules that surround a less polar molecule in solution are \_\_\_\_\_\_\_\_.
relatively immobile and disordered 
  relatively immobile and ordered 
  relatively mobile and disordered 
  relatively mobile and ordered

Answer 3

relatively immobile and ordered

Question 4

Two weak acids, A and B, have pKa values of 4 and 6, respectively. Which statement is TRUE?
Acid A is more likely to be a polyprotic acid than acid B.
Acid B is the conjugate base of Acid A.
For solutions of equal concentration, acid B will have a lower pH.
Acid A dissociates to a greater extent in water than acid B.

Answer 4

Acid A dissociates to a greater extent in water than acid B.

Question 5

Calculate the value of pKa for an acid when Ka = 2.6 × 10-4
-3.59 
  \+3.59 
  -8.25 
  \+8.25

Answer 5

+3.59

Question 6

At the midpoint of a titration curve ________.
The concentration of a conjugate base is 1/2 that of the concentration of a conjugate acid
The pH equals the pKa
The ability of the solution to buffer is at its least effective
The concentration of a conjugate base is twice that of the concentration of a conjugate acid

Answer 6

The pH equals the pKa

Question 7

For a weak acid with a pKa = 6.5, the effective buffering range is usually considered to be \_\_\_\_\_\_\_\_.
 pH 6 to pH 7 
  pH 6.4 to pH 6.6 
  pH 5.5 to pH 7.5 
  Dependent on the molarity of the acid

Answer 7

pH 5.5 to pH 7.5

Question 8

Which substance do you expect to be most soluble in water?
Nitrogen, N2
  Carbon dioxide, CO2
  Methane, CH4
  Ammonia, NH3

Answer 8

Ammonia, NH3