Determination of the molar mass of a liquids فيزياوية ثاني عملي مختبر ثرموديناميك

second Year

Physical Chemistry

Practical

Determination of the molar mass of a liquids
What you can learn about
 Ideal (perfect) and real gases
 Equations of state of ideal
gases
 Gas volumetry
 Vapour-density method
(Victor Meyer)

Principle and tasks
The molar mass of a liquid is determined
by evaporation of the liquid at
constant temperature and pressure
and measuring the volume of the
formed vapour by means of a calibrated
gas syringe. In this experiment
the molar masses of diethyl
ether and methanol are determined.

Related concepts
Ideal and ordinary gases, equations of state for ideal gases, gas
volumetry, determination of molar masses according to the
vapour density method (Victor Meyer).
Principle
The molar mass of a liquid is to be determined by evaporating a
liquid at constant temperature and pressure, and measuring the
volume of vapour formed using a calibrated gas syringe.
Tasks
Determine the molar masses of diethyl ether and methanol.
Discuss the results in terms of the real and ideal behaviour of

Theory and evaluation
The method for the determination of the molar mass of pure liquids
which can be completely evaporated without decomposition
which is described above is based on the theory of ideal
gases. The equation of state for ideal gases is given by

p = Vmol .
R · T

p · V
= n · R · T

p= Pressure
V =Volume
Vmol= Molar volume
R = Gas constant (8.31433 Pa · m3 · K-1 · mol-1)
T Absolute Temperature
n =Number of moles

See the attached file




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