[calvin coolidge]

402.1g of an unknown solute is dissolved in 2.0kg of water. The boiling point elevation of the solution is 2.3 degrees C. What is the molar mass of the solute? Okay, I thought I had this figured out, but most of the people in class had a different answer...I used the formula for BP elevation: deltaT=(molality)(Kbp), and set it up as 2.3=m(.52)<--BP constant for water..and got molality=4.42. Then, set up 4.42=x(moles of solute)/2kg H20...giving me 8.85 moles of solute. I then took mass of solution/moles of solute...2401.2/8.85=271.44 g/mol as my answer, the answer most people got was 45.35 g/mol..

Where did I go wrong?

Thanks for any help...
~CC

[rabolisk]

I then took mass of solution/moles of solute...2401.2/8.85=271.44 g/mol as my answer.

Right there.

[calvin coolidge]

...Got it.....since I'm only concerned w/the solute, I should've done mass solute/moles solute...401.2/8.85=45.33...

Thanks again, Rabolisk!

have a snack my friend!

~CC