A 3000 - mL flask is initailly open while in a room containing air at 1.00 atm and `20^(@)C`. The flask is the closed and immersed in a bath of boiling water. When the air in the flask has reach thermodynamic equilibrium, the flask is opend and air is allowed to escap.The flask is then closed and cooled back `20^(@)C` (A) What is the maximum pressure reached in the flask? (b) How many moles escape when air is released from the flask? (c) What is the final pressure in the flask?

Answer

(a)1.27 atm (b)(0.0268) (0.786 atm)

Explanation

(a) P = 1 atm `T = 20^(@)C` V=3000ml
isothoric process
(b) `P =? T=100^(@)C` V=3000ml
(a) `(P_(2))/(P_(1)) = T_(2)/T_(1) rArr P_(2) =1 xx (373)/(293)` atm= 1.27 atm
(b) when flask opened (Temperature constant)
change in no. of moles `= |(P_(f)V_(f)-P_(i)V_(i))/(RT)|`
`=|(1xx10^(5)xx3000xx10^(-6))/(Rxx373)-(373)/(293)xx(3000xx10^(-6)xx105)/(Rxx373)|`
`|(300)/(Rxx373)-(300xx1.27)/(Rxx373)|`=0.026 moles
(c) final pressure (ischoric processs)
`P_(1)/T_(1) =P_(2)/T_(2) rArr (latm)/(373) = p_(2)/(293)`
`P_(2) = (293)/(373) tam =0.786 atm`