A flask containing 12 g of a gas of relative molecular mass 120 at a pressure of 100 atm was evacuated by means of a pump unitl the pressure was 0.01 atm at the same temperature. What is the approximate number of molecules left in the flask ?

A flask containing 12 g of a gas of relative molecular mass 120 at a p

1.	A flask containing 12 g of a gas of relative molecular mass 120 at a pressure of 100 atm was evacuated by means of a pump unitl the pressure was 0.01 atm at the same temperature. What is the approximate number of molecules left in the flask ?
Answer» <html><body><p><<a href="https://interviewquestions.tuteehub.com/tag/p-588962" style="font-weight:bold;" target="_blank" title="Click to know more about P">P</a>></p>Solution :Initially,`n_(<a href="https://interviewquestions.tuteehub.com/tag/1-256655" style="font-weight:bold;" target="_blank" title="Click to know more about 1">1</a>)=(12)/(120)` mole=0.1 mole, `P_(1)`=100 atm, `T_(1)`=T, `V_(1)`=<a href="https://interviewquestions.tuteehub.com/tag/v-722631" style="font-weight:bold;" target="_blank" title="Click to know more about V">V</a> <br/> After evacuation,`n_(2)`=? `P_(2)=0.01`atm, `T_(2)=T, V_(2)=V` <br/> ApplyingPV=nRT <br/> As V and T an constant, `(P_(1))/(P_(2))=(n_(1))/(n_(2))` <br/> `(100)/(0.01)=(0.1)/(n_(2))"or"n_(2)=(0.1xx0.01)/(100)=(10^(-1)xx10^(-2))/(10^(2))=10^(-5)` mole <br/> No. of <a href="https://interviewquestions.tuteehub.com/tag/molecules-563030" style="font-weight:bold;" target="_blank" title="Click to know more about MOLECULES">MOLECULES</a> left `=(10^(-5))(6.02xx10^(23))=6.02xx10^(18)`</body></html>