Two closed vessels of same volume are joined through a narrow tube and both vessels are filled with air of pressure 90 kPa and temperature 400 K. Keeping the temperature of one vessel constant at 400 K the second vessel temperature is raised to 500 K. The final pressure in the vessels is kPa.
- 100
- 120
- 90
- 105
Answer
(1) 100
Solution
Total moles are conserved; finally both vessels have the same pressure P:
n1+n2=n1'+n2'
P0VR(400)+ P0VR(400)= PVR(400)+ PVR(500)
⇒ 2 90400=P ( 1400+ 1500 )
⇒ 0.45=P 92000
∴ P= 0.45 20009=100 kPa
Answer: (1)