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)

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a) The calculated molar mass will be too low (B).

Explanation: When the flask is not dried after cooling to room temperature, the presence of moisture can contribute to the mass of the flask. This additional mass will incorrectly increase the total mass used in the molar mass calculation, leading to a lower calculated molar mass.

b) The calculated molar mass will be unaffected (C).
Explanation: When some vapor condenses inside the flask during cooling, it does not involve any change in the mass of the substance. The mass used in the molar mass calculation corresponds to the original substance, and the additional condensed vapor does not affect the molar mass calculation.

c) The calculated molar mass will be too low (B).
Explanation: By assuming the flask volume to be exactly 125.00 mL, there might be a deviation from the actual volume. If the actual volume is larger than assumed, the density of the substance will be underestimated, leading to a lower calculated molar mass.

d) The calculated molar mass will be too high (A).
Explanation: Handling the flask several times with oily fingers can lead to the transfer of oil to the flask. This oil adds an additional mass to the flask, which will increase the total mass used in the molar mass calculation. Consequently, the calculated molar mass will be higher than the actual value.