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
The total number of moles is conserved, and finally both vessels have the same pressure P, so
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)