Question

Two closed bulbs of equal volume (V)

containing an ideal gas initially at pressure

pi

and temperature T1

are connected

through a narrow tube of negligible

volume as shown in the figure below. The

temperature of one of the bulbs is then

raised to T2

. The final pressure pf

is :

Answer 1

no of moles of gases in each container is = PiV/RT1

So total no of moles are = 2PiV/RT1

after tube is opened the final pressure in each container becomes equal ,i.e. Pf

so no. of moles in chamber (1) now is = PfV/RT1
and in chamber (2) is = PfV/RT2

So total no. of moles is =  PfV/RT1  + PfV/RT2
 
NOW total no of moles before and after tube opened is same cause no leaking
therefore
2PiV/RT1 =  PfV/RT1  + PfV/RT2

which gives  Pf =  2Pi (T2/T1+T2)
hope this helps