Answer:
52.56 g/mol
Explanation:
Given:
density of CFCL3=5.58 g/mol
density of unknown gas=4.38 g/mol
From ideal gas law PV=nRT
N=number of moles=mass/molar mass
P=pressure
R=gas constant
T=Temperature
Therefore PV= (mass/molar mass)RT……1
Making molar mass the subject of the equation
Molar mass=(mass/V)RT/P……….2
Since density ƥ=mass/volume. Substitute in equation 2 above
Molar mass= ƥ × RT/P……..3
Since the conditions applied does not change as stated in the question. let k=RT/P
Substituting in equation 3, molar mass= ƥ × k……..4
For FREON-11(CFCL3)
Atomic weights are
C=12
F=19
CL3=3*12=36
Molar mass of CFCL3=12+19+36=67
Substitute in equation 4
67=5.58 × k
K=12 L/mol
Applying equation 4 for the unknown gas with 4.38g/mol density
Molar mass=4.38 × 12=52.56 g/mol
