Finding the molecular weight of a solute isotonic with 5% urea

[shaiqbashir]

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 can't 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.

 

[iansmith]

The question has basically 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.