posted by bob on .
Calculate the molarity and mole fraction of a 2.35 m solution of acetone (CH3COCH3) dissolved in ethanol (C2H5OH). (Density of acetone = 0.788 g/cm3; density of ethanol = 0.789 g/cm3.) Assume that the final volume equals the sum of the volumes of acetone and ethanol.
Take enough solution to have 2.35 moles. That mans you have 1 kg solvent (ethanol).
volume ethanol = m/d = 1000g/0.789 = ??.
2.35 mol acetone x molar mass acetone = grams acetone and mass/density = volume.
Add volume acetone to volume ethanol to find total volume.
Then 2.35 moles/L = M
For mole fraction.
moles acetone/total moles.
Check my work.
m doesn't stand for moles. it stands for molality. molality is moles of solute divided by kiligrams of solvent. that might be your problem.