The human red-blood cell membrane is permeable to water but notsucrose. It was f

Question

The human red-blood cell membrane is permeable to water but notsucrose. It was found by trial and error that there was aparticular concentration of sucrose to which cells could be addedwithout either swelling or shrinking of the cells. In aseparate experiment, the freezing point of that particular sucrosesolution is found to be -0.65C. Assume that the interior ofthe cell can be modeled by a KCl solution. Estimate theconcentration of this KCl solution.
I know T=kfm2...so I can find the molality of thesucrose solution. Then I thought I could use theequation =(c2/M2)RT and setting the osmotic pressureequal to zero since there is no swelling or shrinking?
I know T=kfm2...so I can find the molality of thesucrose solution. Then I thought I could use theequation =(c2/M2)RT and setting the osmotic pressureequal to zero since there is no swelling or shrinking?

Explanation / Answer

Given data Tf = -0.65 0C We know that         Kf =-1.86 0C/m KCl is strong electrolyte so it can be dissociated intotwo ions ( K+ and Cl-)    van't Hoff factor for KCl, i =2        Depression infreezing point, Tf = Kf * i * m The concentration of KCl, m=  Tf /Kf * i                                                    = -0.65 0C / (-1.86 0C/m)(2)                                                    = 0.17473 M

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.