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Please help me in finding this relative molecular weight

  1. Oct 15, 2005 #1
    Hi Guys!!

    my question goes like this

    a 5% solution of urea is isotonics with 0.877% of Solute A. Calculate the relative molecular weight of solute A.

    now my dear friend, i know its a very simple question but unfortunately, just cant getting any interpretation. I know isotonics sol means having same no. of moles. and i know that Grahams's law of diffusion as well. Please help me so that i can understand this question.
  2. jcsd
  3. Oct 15, 2005 #2


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    Staff Emeritus
    Science Advisor
    Gold Member

    The question has basicly two component. First you have to find the molarity of the urea solution solution. All the information that you require are in the first 5 words of the question.

    The second part requires you to estimate the molecular weight of the solute A using the molarity of the urea solution and that the solutions are isotonic. So you know the molarity of the solute solution and you know the amount of solute A in the solution. You have to calculate your way up to the molecular weight.
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