Q22 of 31 Page 94

We have 0.5 g of hydrogen gas in a cubic chamber of size 3cm kept at NTP. The gas in the chamber is compressed keeping the temperature constant till a final pressure of 100 atm. Is one justified in assuming the ideal gas law, in the final state?

(Hydrogen molecules can be considered as spheres of radius 1 Å).


Given:


Mass of hydrogen gas=0.5g


Volume of cubic chamber


No. of moles of hydrogen =


No. of molecules of hydrogen is given by



Volume of a single molecule is approximately


Therefore, volume occupied by n molecules of hydrogen =



We know that


From ideal gas equation



When T is constant, then



..(i)


We have




Using eqn.(i) we have




Which is approximately equal to the molecular volume of gas. Hence the intermolecular forces between the molecules cannot be neglected and the ideal gas laws do not follow here.


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