How to Determine Mole Fraction and Mass Percent from Osmotic Pressure Data?

[Mia Vel]

Homework Statement

When 0.32 weight/volume% of sucrose, MgSO4 and KNO3 mixture is dissolved in 997 g of H2O, the osmotic pressure at 25 deg Celsius is 1.25 atm. Calculate the mole fraction and mass percent composition of the original mixture if it contains 15% weight/weight KNO3.

2. Homework Equations
Osmotic pressure= Molarity x Gas constant x Temperature in Kelvin

The Attempt at a Solution

I was able to solve for the molarity of the solution. After it, I don't know what to do next. Can someone please teach me what the next step is and what is the role(meaning) of weight/volume % and weight/weight % in the problem? Thank you in advance. :)

 

[Borek]

When 0.32 weight/volume% of sucrose, MgSO4 and KNO3 mixture is dissolved

I have no idea what it means.

 

[Mia Vel]

My friend told me that when you multiply the given percentage by 100, you will get the total mass of the mixture. I am just not sure whether I should believe him or not.

 

[Borek]

My friend told me that when you multiply the given percentage by 100, you will get the total mass of the mixture.

Doesn't sound correct to me. 30% sulfuric acid doesn't always weight 3000 (and 3000 of what? stones? grams? ounces? pounds?).