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A large flask fitted with a stop-cock is evacuatedand weighed, its massis found to be 134.567 g . It is the filled to a pressure of 735 mm at 31^(@)C with a gas of unknown molecular mass and then reweighed , its mass is 137.456g. The flask is then filled with water and weighed again , its mass is now 1067.9g. Assuming that the gas is ideal, calculate the molar mass of the gas.

Answer» <html><body><p><br/></p>Solution :Mass of <a href="https://interviewquestions.tuteehub.com/tag/water-1449333" style="font-weight:bold;" target="_blank" title="Click to know more about WATER">WATER</a> filling the flask `=(1067.9-134.567)g=933.333 g` <br/> `:.` Volume of flask =Volume of water filling the flask`=933.3 cm^(3)"" (`:'` "density of "H_(2)O=1 g cm^(-3))` <br/> Now,P=735 mm, T=31+273 K=304K, V`=933.3 cm^(3)` <br/> Applying PV=nRT, i.e., `((735)/(760)atm)((933.3)/(<a href="https://interviewquestions.tuteehub.com/tag/1000-265236" style="font-weight:bold;" target="_blank" title="Click to know more about 1000">1000</a>)<a href="https://interviewquestions.tuteehub.com/tag/l-535906" style="font-weight:bold;" target="_blank" title="Click to know more about L">L</a>)=nxx0.0821 L atm K^(-1)mol^(-1)xx304 K` <br/> This gives n=0.036 mol <br/> Mass of 0.036 mol of the gas =(137.456-134.567) g=2.889 g <br/> `:.`<a href="https://interviewquestions.tuteehub.com/tag/massof-2818166" style="font-weight:bold;" target="_blank" title="Click to know more about MASSOF">MASSOF</a> 1 mol of the gas `=(2.889)/(0.036)=80.25 g`</body></html>


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