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Chemistry Homework Help => CBSE XI and XII Chemistry => Topic started by: rajive on November 16, 2017, 01:13:20 PM

Title: ideal gas q13
Post by: rajive on November 16, 2017, 01:13:20 PM
Question 13
Title: Re: ideal gas q13
Post by: uma on November 17, 2017, 05:06:11 AM
Ok
Let us say total volume is V (mixture )
So V is also the volume of pure oxygen
Now rate of diffusion of mixture = V mL/ 245 sec
Rate of diffusion of pure oxygen = V mL/ 220sec
Total moles in the mixture are 5 if we take 4 mol of Oxygen gas and one mole of unknown gas.
Let us say molar mass of unknown gas as x
so molar mass of the mixture will be   (4 O2 + x)/5 = (128+x)/5

Ratio of rate of diffusion  of mixture and pure oxygen gas
you will get
((128+x))/(5(32))  =  ( 245/220)^2
solve it for x

Title: Re: ideal gas q13
Post by: rajive on November 17, 2017, 01:14:10 PM
Maam I did the same way and got same answer, 70 something but the ans is 133.Don't know what we are doing wrong.
Help