From the time the mass of the flask is first measured in Part A.1 until the time
ID: 522268 • Letter: F
Question
From the time the mass of the flask is first measured in Part A.1 until the time it is finally measured in Part B. 3, it is handled a number of times with oily fingers. Does this lack of proper technique result in the molar mass of the vapor in the flask being reported as too high or low or as unaffected? Explain. The aluminum foil is pierced several times with large pencil-size holes instead of pin-size. a. How will this oversight in the procedure affect the mass of vapor measured in Part B.3, too low, too high, or unaffected? Explain. b. Will the reported molar mass of the liquid be reported too low, too high, or unaffected? Explain. The flask is completely filled with vapor only when it is removed from the hot water both in Part B.3. 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. Suppose the thermometer is miscalibrated to read 0.3 degree C higher than actual. Does this tan actual. Does this error in calibration result in the molar mass of the vapor in the flask being reported as too high, too low, or as unaffected? Explain. 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.Explanation / Answer
The background information was required; however, I will base my answers on the assumption that you were doing the lab for calculation of molar mass of a gas/compound.
2) In general, the flask must not be contaminated with any moisture, oil or grease during the experiment. This is because we take the mass of the initial dry flask and then we weigh the final mass of the flask and the contents after the reaction is over. Any oil on the surface of the flask will increase the final mass of the flask and the contents and the weight recorded will be higher than the actual weight. This will lead to errors in calculation and the calculated molar mass of the vapor will be higher.
3) The calculated mass and hence the molar mass of the vapor will be too low. This is because the holes are too large for the vapor to escape and significant fraction of the vapor will escape from the flask. Therefore, the mass of vapor in the flask will be too low and hence the calculated molar mass will be lower than the actual value.
Pin holes are tiny holes and the mass of the vapor lost will be considerably low, leading to insignificant errors in the calculated molar mass.
6) Need the actual volume to answer the question.
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