How Much Sucrose Is Needed to Lower Water's Vapor Pressure by 2 mmHg?

[sw3etazngyrl]

How many grams of sucrose (C12H22O11) must be added to 552 g of water to give a solution with a vapor pressure 2.0 mmHg less than that of pure water at 20 degrees C? (The vapor pressure of water at 20 degrees C is 17.5 mmHg.)

I tried it out, and this is my work.
change in P=mole fraction*P in degrees
2.0mmHg=X(17.5mmHg)
X=0.11 moles

552 g H2O * 1 mole/18.02g = 30.3 mol

0.11(30.3 + x)=30.3
3.33+0.11x=30.3
x=245.18 mol

245.18 mol sucrose * 324.34g/1 mol=83000

 

[Gokul43201]

Hello sw3etazngyrl, we need to first see your effort. https://www.physicsforums.com/showthread.php?t=94384