Calculating Percentage of Dissociated N2O4 Molecules: Vapour Density Question

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SUMMARY

The discussion focuses on calculating the percentage of dissociated N2O4 molecules into NO2, given a vapour density of 35. The molar mass of N2O4 is determined using the formula: molar mass = 2 * Vapour Density, resulting in a molar mass of 70 g/mol. The reaction is represented as N2O4 dissociating into 2NO2, with the initial moles of N2O4 denoted as 'a' and the degree of dissociation as 'α'. The solution involves setting up equations based on the dissociation and using the observed molar mass as a weighted average of the components.

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navneet9431
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Homework Statement


The vapour density of a sample of N2O4 gas is 35. What per cent of N2O4 molecules are dissociated inNO2?

Homework Equations


molar mass = 2 * Vapour Density

The Attempt at a Solution


I tried to solve this question this way,
Let the initial number of moles of N2O4=a
and, assume that the degree of dissociation is α
So,the reaction would be

N2O4 ---------> 2NO2
a ---------------0 (Before Dissociation)
a(1-α)------------2aα (After-dissociation)

And also since VD of N2O4 gas is 35. So,the mass of N2O4 gas would be=35*2=70.
But i do not know what i shall do next?
I will be thankful for any help!
 
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navneet9431 said:
molar mass = 2 * Vapour Density

Hint: observed molar mass is a weighted average of the molar masses of components.
 

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