date were collected for trial 1 to determine the molar mass of a nonvolatile sol
ID: 879120 • Letter: D
Question
date were collected for trial 1 to determine the molar mass of a nonvolatile solid solute when dissolved in cyclo-hexane.
b. What information is to be extracted from each data plot? 5. a. Data were collected for Trial 1 to determine the molar mass of a nonvolatile solid solute when dissolved in cyclo- hexane. Complete the table for the analysis (See Report Sheet). Record calculated values with the correct number of significant figures. B Freezing Point of Cyclohexane plus Calculation Zone Unknown Solute 1014 0.255 2. Part C.4 Mass of cyclohexane (g) 3. Mass of added solute (g) Calculations 1. ky for cyclohexane C. kg/mol) 2. Freezing point change, 7CC) 3. Mass of cyclohexane in solution (kg) 4. Moles of solute, total (mol) 20.0 3.04Part C.6 Show calculation. 5. Mass of solute in solution, total (g) 6. Molar mass of solute (g/mol) Show calculation. 5 h h For Trials 2 and 3, the molar mass of the solute was 151 g/mol and 143 g/mol respectively.Explanation / Answer
C.
3. Mass of cyclohexane in solution (kg) = 10.14 g/1000 = 0.01014 kg
4. moles of solute
delta Tf = m x kf = (moles of solute / kg of solvent) x kf
m = molality
3.04 = moles of solute x 20 / 0.01014
moles of solute = 1.54 x 10^-3 mols
5. mass of solute in solution = 0.255 g
6. molar mass of solute
moles = mass of solute / molar mass
molar mass of solute = mass of solute / moles of solute
= 0.255 g / 1.54 x 10-3 moles
= 165.584 g/mol
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.