Data Collection From the procedure 1. Fill your 400 mL beaker about 3/4 full with DI water. Place several boiling stones
Posted: Mon Jul 11, 2022 1:38 pm
- Data Collection From The Procedure 1 Fill Your 400 Ml Beaker About 3 4 Full With Di Water Place Several Boiling Stones 1 (67.68 KiB) Viewed 40 times
- Data Collection From The Procedure 1 Fill Your 400 Ml Beaker About 3 4 Full With Di Water Place Several Boiling Stones 2 (30.98 KiB) Viewed 40 times
Data Collection From the procedure 1. Fill your 400 mL beaker about 3/4 full with DI water. Place several boiling stones in the water and place the beaker with the water on a hot plate. 2. Start heating the water to boiling using a mid-scale setting on the hot plate. 3. While the water bath is heating, stand up a test tube in your 30 mL beaker and weigh both to the nearest 0.001 g. Record the mass on your data sheet. 4. Repeat for a total of 5 trials. Mass of empty test tube and beaker (g) From the procedure 4. Add about 9 grams of stearic acid to the test tube and weigh the test tube, stearic acid and beaker to the nearest 0.001 g. Record the mass on your data sheet. 5. Determine the mass of stearic acid using difference methods. Mass of test tube, beaker, and stearic acid (g) Time and Temperature Data: Cooling Curve of Stearic Acid From the procedure 6. Place the test tube with the stearic acid in your water bath and heat it until it is a liquid at 85 °C. 62.100 71.087
Report Table FP.1: Freezing Point of Solvent (Stearic Acid) Time and temperature data for the freezing point of stearic acid Time (Seconds) 0 30 60 90 120 150 180 210 240 270 1st Cooling Curve Temperature (°C) 86.6 85.4 84.2 83.0 81.8 80.7 79.6 78.5 77.5 76.5
300 330 360 390 420 450 480 510 540 570 600 630 660 690 75.5 74.5 73.6 72.8 72.0 71.3 70.6 70.0 69.6 69.4 69.3 69.3 69.3 69.3
720 750 780 810 840 870 900 Time and Temperature Data: Cooling Curves for Solution with Unknown From the procedure 11. Obtain an unknown compound and record its number on your data sheet. 12. Weigh out approximately 1 gram to the nearest 0.01 g and record the mass on your data sheet. Unknown number Mass of unknown used From the procedure 69.3 69.3 69.2 69.2 69.2 69.2 69.2 2 1.009
Mass of unknown used From the procedure 13. Add the unknown compound to the test tube containing the stearic acid. 14. Place the mixture in the hot water bath and heat it until its temperature reaches 85 °C. Report Table FP.2: Freezing Point of Solution Time and temperature data for the freezing point of unkown solute Time (Seconds) 0 30 15. Stir the molten mixture and repeat the above procedure used for pure stearic acid for the solution of the unknown and stearic acid. 60 90 120 1.009 2nd Cooling Curve Temperature (°C) 85.3 83.9 82.5 81.1 79.8
150 180 210 240 270 300 330 360 390 420 450 480 510 540 78.5 77.2 75.9 74.7 73.5 72.4 71.3 70.3 69.3 68.4 67.5 66.8 66.1 65.6
570 600 630 660 690 720 750 780 810 840 870 900 65.4 65.3 65.3 65.3 65.2 65.2 65.2 65.2 65.2 65.1 65.1 65.1
720 750 780 810 840 870 900 Time and Temperature Data: Cooling Curves for Solution with Unknown From the procedure 11. Obtain an unknown compound and record its number on your data sheet. 12. Weigh out approximately 1 gram to the nearest 0.01 g and record the mass on your data sheet. Unknown number Mass of unknown used From the procedure 69.3 69.3 69.2 69.2 69.2 69.2 69.2 2 1.009
(34pts) Determination of Freezing Points Use the data tables shown above to make two plots of cooling curves using a graphing program, like Excel. Each cooling curve is a plot of temperature (y-axis) versus time (x-axis), and contains a cooling porting (when the liquid is cooling) and a freezing portion (when the liquid is turning to solid). You will need to generate a trendline for each portion of the cooling curve. In order to do this, you will need to identify which points to include in the cooling portion of the curve and which points to include in the freezing portion of the curve. For each cooling curve, you will need to identify three points • the last temperature measurement to include in the cooling portion of the curve • the first time to include in the freezing portion of the curves • the last time to include in the freezing portion of the curves
Report Table FP.3: Freezing Point Determination Calculations for the cooling curve of stearic acid and the unknown solution Cooling Curve #1 Final time to include in cooling portion Slope of cooling portion y-Intercept of cooling portion First time to include in freezing portion Final time to include in freezing portion Slope of freezing portion Choose. Choose... Choose.. Choose... Choose. Choose... Table view List view Cooling Curve #2 Choose.. Choose... Choose.. Choose... Choose. Choose...
portion Final time to include in freezing portion Slope of freezing portion y-Intercept of freezing portion Time at which 2 lines intersect (seconds) Calculated freezing point (°C) (15pts) Determination of Molar Mass Choose... Choose.. Choose... Choose... Choose.. Choose... Complete the calculations in the following table to determine the molar mass of the unknown added to stearic acid. Report Table FP.4: Determination of molar mass
Report Table FP.4: Determination of molar mass Calculations for the molar mass of the unknown solute Mass of test tube, beaker, and stearic acid (g) Mass of test tube and beaker (g) Mass of stearic acid (g) Unknown number Mass of unknown (g) Freezing point of stearic acid (calculated above) (°C) Freezing point of solution (calculated above) (°C) Freezing point depression (°C) Table view List view Result 71.087 62.100 2 1.009
Mass of unknown (g) Freezing point of stearic acid (calculated above) (°C) Freezing point of solution (calculated above) (°C) Freezing point depression (°C) Molality of unknown in solution (m) Moles of unknown in solution (mol) Molar mass of unknown (g/mol) (5pts) What is most likely the identity of your unknown solute? Choose... 1.009