An open vessel at 300 kelvin is heated until 0.6 parts of the air in it has been expelled.Assuming that the volume of the vessel remain constant,find the temperature to which the vessel has been heated.
here in this question I am having problem that in the solution part it is given that volume of air initially is V and volume of air at 300 k=0.4V and on heating it would again become V.But I understood from the question that on heating 0.4 have been left in the vessel,then how he can say that on heating the volume would be V.please tell me where I am wrong.If I have understood the question incorrectly then please explain it to me, & also write the solution and explain it.
thank you

Read the question again. The volume expelled is AIR: volume here is a measure of the amount of air - - the n in PV = nRT.

Solve using those numbers and you will get the Temperature.