Exam 2 - Interfacial Phenomena

Question 1

The tension between which phases is interfacial?

A.Gas phase and gas phase

B.Gas phase and liquid phase

C.Gas phase and solid phase

D.Liquid phase and solid phase

E.None of the above

Answer 1

D.Liquid phase and solid phase

Question 2

Answer 2

C.

Question 3

—Which non-ionic surfactants are more hydrophilic, tweens or spans?

—A.Tweens

B.Spans

C.Tweens and spans are equally hydrophilic

Answer 3

—A.Tweens

Question 4

—An increase in polyoxyethylene chain length would

—A.Increase HLB

B.Decrease HLB

C.Not affect HLB

Answer 4

—A.Increase HLB

Question 5

Adsorption from solution on to solid surfaces may occur if:

A.Dissolved molecules and the solid surface have chemical groups capable of interacting

B.Solute is surface active

C.Surface area of the solid is high

D.A and B only

E.A, B and C are correct

Answer 5

E.A, B and C are correct

Question 6

—The greater the affinity of the solute for the liquid, the ________ the tendency to adsorb to a solid

—A.higher

B.lower

Answer 6

B.lower

Question 7

—The more polar the solute, the adsorption that occurs from water will be

—A.Increased

B.Decreased

C.Unaffected

Answer 7

B.Decreased

Question 8

—Adsorption will tend to be greatest when the solute is in its:

—A.Ionized form

B.Unionized form

C.Ionization does not affect adsorption

Answer 8

B.Unionized form

Question 9

—Adsorption will tend to be greatest at:

—A.High pH for weak acids; low pH for weak bases

B.Low pH for weak acids; high pH for weak bases

Answer 9

B.Low pH for weak acids; high pH for weak bases