We only did 2 trials. Only questions 2,4, & 6 are required.

Experiment 12 Report Sheet Molar Mass of a Volatile Liquid Doro 241/202200 sec Desk No Date Name A. Preparing the sample Trial Trial Trial Unknown number Methanol 89.5569 g 1. Maw of dry Rask, foil and rubber hande B. Vaporize the Sample 1. Instructor's approval of apparatus 2. Temperature of boiling water (CR) 95 368.15 95 3605 2. Mas of dry Pack fosil, rubber bund, and vapor (e$9.67869 89.6470 C. Determine the Volume and Pressure of the Vapor 1. Volume of 125 ml flask.) - 100.48+ = total volume 0.148 L 754 0.999 2. Atmospheric pressure (for, atm) D. Calculations 1. Moles of vapor, mor 2. Mass of vapor, (8) 3. Molar mass of compound (mol) 4. Average molar mass (g/mol Data Analysis, 5. Standard deviation of molar mass Data Analysis, 6. Relative standard deviation of molar mass (RSD) Data Analysis, Show the calculation for the standard deviation and the relative standard deviation (as RSD) of the molar mass of the unknown. Data Analysis, C and D. Experiment 12 179 (OptionalAs instructor for the same of your calq Udt We and for your compound repeat the calculate for the most vaperhelorTheme curate molar man of the compound E Calculations (van der Waals' equation) Unknown number Trial Trio 1. Moles of vapor. Trial 2. Mass of vapor.) 2 Molar mass of compound Como 4. Average molar massol Calculation of from van der Waals equation for Trial Show work here Laboratory Questions Circle the questions that have been assigned 1. Part A.1. The mass of the flask (before the sample in placed into the task) is measured when the outside of the flaskis wet. However, in Part B.3. the outside of the flask is dried before its mass is measured a. Will the mass of vapor in the flask be reported as too high or too low, or will it be unaffected? Explain. b. Will the molar mass of vapor in the flask be reported as too high or too low, or will it be affected? Explain. Part A.1. From the time the mass of the Mask is first measured in Pan A.1 until the time it is finally measured in Pa B.3. it is handled a number of times with caly fingers. Does this lack of proper technique result in the molar mass of the vapor in the flask being reported as too high or too low or as unaffected? Explain 3. Purt A2. The aluminum foil is pierced several times with large pencil-size holes instead of pin-site. a. How will this oversight in the procedure affect the mass of vapor measured in Pan B.3. too low to high unaffected? Explain b. Will the reported molar mass of the liquid be reported too low to high or unaffected? Explain. Part B.2. The flask is completely filled with vapor only when it is removed from the hot water hath in Part B.2. However, when the flask cools, some of the vapor condenses in the flask. As a result of this observation, will the reported molar mass of the liquid be too high, too low, or unaffected? Explain. 5. Part B.2. Suppose the thermometer is miscalibrated to read 0.3C higher than actual. Does this crror in calibration result in the molar mass of the vapor in the flask being reported as too high, too low, or as unaffected? Explain. Part C1. If the volume of the flask is assumed to be 125 mL instead of the measured volume, would the calculated molar mass of the unknown liquid be too high, too low, or unaffected by this experimental error? Explain 7. Pan C.2. The pressure reading from the barometer is recorded higher than it actually is How does this affect the reported molar mass of the liquid: too high, too low, or unaffected? Explain. 180 Molor Mass of a Volatile liquid