Data Experimental and Graphs Mass of cyclohexanol: 9.3 grams Time (s) Temperature (C) 10 38 20 36 30 34 40 33 50 32 60 31 70 30 80 29 90 28.5 100 28 110 27 120 27 130 26 140 26 150 25.5 160 25 170 24 180 24 190 24 200 24 210 23 220 22.5 230 22 240 22 250 21 260 21 270 21 280 21
Mass of solute added to cyclohexanol: .71 g Code Number of Solute Used: B Time (s) 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 Temperature (C) 60 51 45 40 36 34 32 30 29 27 26 26 25 25 24 23 23 23 22 22 22 21.5 21 20.5 20 20
Red=cyclohexanol+B Blue=cyclohexanol
Freezing Point of Cyclohexanol: 24 C Freezing Point of Cyclohexanol Solution: 10 C Tf = 14 C Calculations: 3. Kf of cyclohexanol = 39.4 C/m Molality = Tf / kf m = 14 C / (39.4 C/m) m = 0.355 mol/kg 4. moles of solute = (molality)(kg of solvent used) moles of solute = (0. 0.355 mol/kg)(0.0093 kg) 0.0033015 moles of solute
5. molar mass = (grams of solute added) / (moles of solute) molar mass = (0.71 grams) / (0. 0033 moles of solute) molar mass = 215.15 g/mol Conclusions/Discussions: Error: Octadecanol = 270 g/mol mass Molar =215.15 g/mol
According to our data, the molar mass of the compound we added to the cyclohexanol was less than the octadecanol. Since we know that the compound was octadecanol, we can only make one assumption about this experiment. This experiment has a significant amount of error. The error in the data is 20.3%; which is far outside the acceptable percentage. This could come from and small measurement, human, or equipment error. One significant problem was that we were working with a solvent that wasn't water. This means any water in the test tube would affect our data. On top of this, we feel that some cyclohexanol was lost in transfer, which would easily skew data. We were working with small amounts of solution, so any minute mistake is amplified in the data. I feel that if we were able to replicate this experiment with larger amounts of solution, we would get a more defined step in the graph, as well as minimizing any errors made during the experiment. This would happen because the fluid would take longer to freeze, and mistakes would have to be more significant to ruin the data.