Deck 12: Osmosis and Osmotic Pressure

Question 1

Va n't H of f's lim iting law for os m otic pre ss ur e is 6 P - o6w

A) JV = Lp ( )
B) w = RT ln C
C) w = $ RT ln C
D) w = RT C
E) Lp = w a4 / 8yð

Answer 1

D

Question 2

Doubling the thickness of a m icroporous m em brane sh ould have what effect on pressure-driven flow acr oss it?

A) Reduce flow to 1/2 of its previous value
B) Reduce flow to 1/4 of its previous value
C) Increase flow to 2X its previous value
D) Increase flow to 4X its previous value
E) Increase flow to 8X its previous value

Answer 2

A

Question 3

An approximate equation for the pressure-driven volume flow across a microporous m em bran e with n p or es pe r un it ar ea is w a2 / yð 6 P

A) Q V = n w
B) Q V = A n
A4 / 8
C) Q V = - AD ( 6 P - o6w /ð
D) Q V = n w a4 / 8yð 6 P
E) None of the above

Answer 3

B

Question 4

D ou blin g th e v isc os ity of a flu id th at is pre ss ur e- dr ive n a cr os s a m icr op or ou s m em br an e s ho uld

A) Double the flow
B) Increase the flow to 16X its previous value
C) Halve the flow
D) Have little effect on the flow
E) Decre ase the flow by a factor of 4

Question 5

Doubling the rad ius of t he po re s in a microporous mem brane should affect pressure-driven flow by

A) Increasing it to 2X its previous value
B) Increasing it to 4X its previous value
C) Increasing it to 8X its previous value
D) Increasing it to16X its previous value
E) Increasing it to 32X its previous value

Question 6

The be st p re dic tor of t he os m otic pre ss ur e is

A) So lute so lubility
B) Co nce ntration of so lute
C) Concentration of water in a solution
D) Vapor pressure depression
E) The reflection coefficient

Question 7

The reflection coefficient

A) De pen ds o n the sha pe a nd s ize of the solute
B) Depends on the number of pores in the mem brane
C) Depends on the shape and size of the pores in the mem brane
D) Determ ines the flow produced by a given hydrostatic pressu re
E) Both A and C are correct

Question 8

The coe fficien t that co rrec ts the obs erve d os m otic pr ess ure f or an im perf ectly sem i-p er m ea ble m em br an e is

A) $
B) o
C) Lp
D) p
E) Lp o

Question 9

Consider a microporous membrane that separates a solution on the left with concentration CL from a solutio n on the righ t at C R. The permeability for the solute, p > 0. If CL > C R, the presence of pressure-driven flow from right to left should

A) Increase the net flux of solute from left to right by solvent drag.
B) Increase the net flux of solute from right to left by solvent drag.
C) Decrease the net flux of solute from left to right by solvent drag.
D) Decrease the net flux of solute from right to left by solvent drag.
E) No t affe ct ne t flux of solute from left to righ t.

Question 10

Red blood cells were placed in a solution of 3% glucose. W e should expect

A) T he rbc s s we ll be ca us e th is s olu tion is h ype rto nic
B) The rb cs s w ell be cau se th is so lutio n is h ypo ton ic
C) T he rbc s s hr ink be ca us e th is s olu tion is h ype rto nic
D) T he rbc s s hr ink be ca us e th is s olu tion is h ypo ton ic
E) T he rbc s n eith er sh rin k n or sw ell b ec au se this so lutio n is iso ton ic

Question 11

Red blood cells were placed in a solution of 1.2 % NaCl. W e should expect

A) T he rbc s s we ll be ca us e th is s olu tion is h ype rto nic
B) T he rbc s s we ll be ca us e th is s olu tion is h ypo ton ic
C) The rb cs s hrin k be cau se th is so lutio n is h ype rton ic
D) T he rbc s s hr ink be ca us e th is s olu tion is h ypo ton ic
E) T he rbc s n eith er sh rin k n or sw ell b ec au se this so lutio n is iso ton ic