Change in pressure using PV=nRT

[rinarez7]

1b]1. Gas is confined in a tank at a pressure of
6.5 atm and a temperature of 9.4◦C.
If half of the gas is withdrawn and the
temperature is raised to 62.4◦C, what is the
new pressure in the tank? Answer in units of
atm.



2. PV=nRT
Ti= 9.4 C + 273= 282.4K
Tf= 62.4 C +273= 335.4K




3. PV= nRT, n and R are constants, therefore I used PV= T
So, initially, 6.5atmVi= 282.4K giving, Vi = 43.446

I then used (1/2) 43.446 as Vf and solved for Pf
Pf= Tf/ Vf=> 15.439 atm

But this isn't right, I know. What am I missing?? .

 

[nicksauce]

My thought would be that "half of the gas is withdrawn" means that the number of particles n is halved, and the volume is kept constant, not the other way around.

 

[Confundo]

It doesn't mention the volume has been reduced by a half, the amount of gas has been reduced by a half so you need to use 0.5n.

 

[rinarez7]

Thanks to the both of you!