Biochem question

[dentheartthrob]

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A 0.2 mole/liter NaCl solution and a 0.2 mole/liter glucose solution are separated by a membrane that is impermeable to these solutes but is permeable to water. which of the following statements is correct?

a. there will be no movement of H20 to either of the solution
B. water will go from the glucose to the salione soln
c. water will go from the saline to the glucose soln
d. concentration of glucose will decrease
e. concentration of NaCL will increase

my guess is c, but im just saying this because the glucose moluecule is much bigger then the NaCl molecule. Does anyone else have a better explanation or a different answer?

 

[perennialdent]

its b

 

[collegeboy30000]

b.
b/c NaCl dissociates to Na+ and Cl- when solvated by water. Glucose however does not "breakup".

 

[dentheartthrob]

b.
b/c NaCl dissociates to Na+ and Cl- when solvated by water. Glucose however does not "breakup".

well this is the thing that gets me ,at 0.2 mole/liter NaCl converts to 11.7g/liter while glucose has 36g/liter, thus the solute concentration of glucose is more compaed to the solute concentration of NaCl. And by defintion osmosis is the net movement of water across a partially permeable membrane from a region of high solvent potential to an area of low solvent potential, up a solute concentration gradient, regardless if NaCl dissociates the membrane is only permeable to H2O. Does this sound about right?

 

[pol37]

don't over complicate it - simple rule always chose Na in this chase. b 😉

 

[s m i l e 2007]

Here only see dissociation but not the size so nacl dissociates in Na+ and cl- and glucose can not ,so water goes form glucose to Na+ cl-.

correct me if i am wrong

 

[dentheartthrob]

Here only see dissociation but not the size so nacl dissociates in Na+ and cl- and glucose can not ,so water goes form glucose to Na+ cl-.

correct me if i am wrong

yeah mah bad, the explanation to this is that the osmotic pressure of a so'ln depends basically on the number of solute particles present and not their nature. So since NaCl dissociates, there will be actually be two moles of solute enitites per 0.2 mole of NaCl dissolved, making it 0.4 moles greater then .2 moles. And since each ion interacts with water, it the would decrease the concentration of free diffusable water molecue, so the correct answer is b....This kinds of questions make me feel sad, its suppose to be easy, but I end up over thinking about the answer and still getting it wrong

 

[Ice2remember]

hi denthearthrobe,

You look like u really know u r basics and subject well.u have answers,opinions,explanations to most of the questions being discussed.So what's u r secret besides hardwork which is obvious?😀.So when r u taking the test?

 

[dentheartthrob]

hi denthearthrobe,

You look like u really know u r basics and subject well.u have answers,opinions,explanations to most of the questions being discussed.So what's u r secret besides hardwork which is obvious?😀.So when r u taking the test?

thanks, some of the basic i forgot already, so i just end up googling the internet to relearn something over again. 😕 I plan on taking my exam late august.