What is the main source of error in the determination of the molar mass?

What is the main source of error in the determination of the molar mass?

The primary source of error is in the mass measurement, which had a standard deviation of 1.5%. The method could be improved by using a more precise balance to decrease the error in the mass measurements. It is also interesting to note that the molar mass was found to be slightly smaller than the literature value.

Why is it necessary to dry flask completely before vaporizing the liquid?

It was important that the flask be completely dry before the unknown liquid was added so that water present would not vaporize when the flask was heated.

Why is it not necessary to weigh the flask and the liquid unknown before the initial heating?

It is not necessary to weigh the amount of liquid initially put into the flask because a large amount of the liquid is excess. It was necessary to weigh the cooled vapor (liquid) to determine the weight of the vapor that filled the flask.

How is the pressure of the vaporized liquid determined in the molar mass of a volatile liquid experiment?

Liquid is vaporized into a fixed volume vessel at a measured temperature and barometric pressure. The volume of the flask is measured by filling the flask with water, when open to atm, measure pressure. This will determine the molar mass of the low boiling point liquid.

What is the molar mass of oxygen gas?

15.999 u
Oxygen/Atomic mass

What is the molar mass of water?

18.01528 g/mol
Water/Molar mass

What is the purpose of filling the flask with water up to its brim?

It is reached by diluting a known quantity of the investigated solution in a conical flask, adding distilled water to the mark to it. This allows you to determine the exact concentration of the test solution and determine the accuracy of the study by conducting a series of similar experiments.

How will the molar mass be affected higher or lower if you did not heat the flask long enough to vaporize all the gas explain?

(a) You did not completely vaporize the liquid when you heated it. When not completely vaporized then pressure value was less than actual. As a result, the value of n would be less. Molar mass value would be incorrectly high.

Will the mass of vapor in the flask be reported?

The molar mass of vapor in the flask will be reported as too low because the molar mass of the compound is directly proportional to the mass of the vapor. As the mass of the vapor decreases, its molar mass will also decrease.

Will the molar mass of vapor in the flask be reported as too high or too low or will it be unaffected explain?

What is the molar mass of the volatile liquid?

number of moles = n = pV/RT . But we go one step further, because we will also measure the mass of the evaporated liquid. Knowing the mass and the number of moles will allow us to compute the molar mass of the liquid: molar mass = (mass)/(number of moles).

Why do you add water to an acid flask?

The volume and concentration of base equals the number of moles of base. This is use to determine the number of moles of acid in the flask. Since you are interested in the number of moles of acid in the flask, why would adding water (which doesn’t have any acid) change the number of moles of acid?

What happens when you add water to Erlenmeyer flask?

If you were to calculate the concentration of acid from the titration, and you add distilled water to the erlenmeyer flask, then yes, you would affect the [H3O+(aq)] since increasing volume with same number of moles decreases the concentration of the solute (or analyte) and thus increases the pH of the solution…

How is the molar mass of a volatile liquid determined?

Introduction: The molar mass of an unknown volatile liquid can be determined by placing an excess amount of the liquid in a pre-weighed flask and heating it up in a water bath. As the liquid evaporates, its vapor replaces the air in the flask, expelling the air and excess vapor through a pinhole at the top.