a solution of 1.15g of solute dissolved in 25.0 mL of H2O at 25 degree C has a boiling point of 100.85 degree C. What is the molar mass of the solute if it is a nonvolatile nonelectrolyte and the solution behaves ideally ( s of H2O at 25 degree C = 0.997 g/mL) ?

I need help with this problem!
what formulas should I use, and how can I start with this?

Thank you for any help.

Question

a solution of 1.15g of solute dissolved in 25.0 mL of H2O at 25 degree C has a boiling point of 100.85 degree C. What is the molar mass of the solute if it is a nonvolatile nonelectrolyte and the solution behaves ideally ( s of H2O at 25 degree C = 0.997 g/mL) ?

I need help with this problem! 
what formulas should I use, and how can I start with this?

Thank you for any help.

surry99 · Answer

Look up boiling point elevation

surry99 · Answer

you will find a formula that will get you started.

moonlight93 · Answer

can you check  my work, and my final answer please. 

(100.85 - 100.00) °C / (0.512 °C/m) = 1.660 m 

(1.660 mol/kg) x (25.0 mL x (0.997 g/mL) / (1000 g/kg)) = 0.04138 mol 

(1.15 g) / (0.04138 mol) = 25.27 g/mol

moonlight93 · Answer

@surry99

surry99 · Answer

Method looks fine, math looks good as well.

moonlight93 · Answer

thank you

moonlight93 · Answer

the final answer should be 28