Determining Molar Mass: Impact of Procedural Errors on Experiment Results
How would each of the following procedural errors affect the results to be expected in this experiment?
Give your reasoning in each case.
(A) Not all of the liquid was vaporized when the flask was removed from the water bath.
(B) The flask was not dried before the final weighing with the condensed vapor inside.
(C) The flask was left open to the atmosphere while it was being cooled, and the stopper was inserted just before the final weighing.
(D) The flask was stoppered and removed from the bath before the vapor had reached the temperature of the boiling water. All the liquid had vaporized.
Impact of Procedural Errors on Experiment Results:
The aforementioned procedural errors in the experiment can lead to inaccurate results, including underestimation or overestimation of the substance's molar mass and potential inaccuracies in temperature measurements.
Explanation: In this given context, these procedural errors would have various impacts on the experiment's results:
(A) Not all of the liquid was vaporized when the flask was removed from the water bath: This would likely result in an underestimation of the substance's molar mass because some of it remained in liquid form and would not contribute to the mass of the gas measured.
(B) The flask was not dried before the final weighing with the condensed vapor inside: This would cause an overestimation of the substance's mass because the extra mass from the water would also be included.
(C) The flask was left open to the atmosphere while it was being cooled, and the stopper was inserted just before the final weighing: This could introduce outside air into the flask, which might contain water vapor or other gases that could affect the results, leading to a potential overestimation of mass.
(D) The flask was stoppered and removed from the bath before the vapor had reached the temperature of the boiling water: This could lead to inaccurate temperature measurements, which could potentially lead to underestimation of the vapor's mass due to lower vapor pressure than expected at the boiling point.