For each of the following experimental conditions determine whether molar mass would be:
1) too high, B) too low or C) unaffected. In each case, /explain/ how this result occurs
a) after removing the flask from the water bath, the experimenter cools the flask to room temperature but does not dry it. The calculated molar mass will be: A) B) C)
b) the flask is removed form the water bath containing vapor only, the experimenter cools the flask to room temperature and some vapour condenses inside the flask. The calculated molar mass will be: A) B) C)
c) the flask volume is not measured; instead the experimenter assumes the flask volume to be exactly 125.00mL. The calculated molar mass will be: A) B) C)
d) From the time the mass of the unused flask assembly (flask, foil, and elastic band) is recorded the flask is handled several times with oily fingers. The calculated molar mass will be: A) B) C)
a) The calculated molar mass in this case would be too low (B). When the flask is not dried after cooling, any moisture present in the flask will add to the mass measurement. This extra mass will be included in the calculation of molar mass, leading to a lower value than the actual molar mass of the substance.
b) The calculated molar mass in this case would be unaffected (C). The condensation of vapor inside the flask does not affect the mass measurement or the molar mass calculation. The molar mass is determined based on the mass of the substance, and the presence of condensed vapor does not change the mass of the substance.
c) The calculated molar mass in this case would be unaffected (C). Assuming the flask volume to be 125.00 mL does not directly affect the mass measurement or the molar mass calculation. The molar mass is determined based on the mass of the substance, not the volume of the flask. However, assuming an incorrect volume may lead to inaccurate density calculations, which could indirectly affect the determination of molar mass.
d) The calculated molar mass in this case would be too high (A). When the flask is handled with oily fingers, some of the oil residue may transfer to the flask and increase its mass. This additional mass will be included in the calculation of molar mass, resulting in a higher value than the actual molar mass of the substance.
a) After removing the flask from the water bath, cooling it to room temperature without drying it would lead to the calculated molar mass being too high. This is because any residual water droplets that remain on the flask's surface will contribute to the overall mass measured. The presence of additional water mass will lead to an inflated molar mass calculation.
b) Removing the flask from the vapor-only water bath, cooling it to room temperature, and having some vapor condense inside the flask would result in the calculated molar mass being too low. Condensation of vapor inside the flask would introduce additional mass, which would falsely lower the measured mass of the gaseous substance. Consequently, the calculated molar mass would be lower than the actual value.
c) Assuming the flask volume to be exactly 125.00 mL without measuring it would have no effect on the calculated molar mass. The molar mass is determined by dividing the mass of the substance by its volume, so as long as the mass measurement is accurate, the assumed volume will not impact the molar mass calculation.
d) Handling the flask multiple times with oily fingers after recording the mass of the unused flask assembly would lead to the calculated molar mass being too low. The oily residue left on the flask's surface will have additional mass, leading to a higher total mass being measured. As a result, the molar mass calculation will be underestimated since the measured mass will be lower than the actual mass.