Two closed vessels of equal volume are connected through a narrow tube.

Initially:

• Pressure = 90 kPa
• Temperature = 400 K

One vessel remains at 400 K while the second vessel is heated to 500 K.

Find the final pressure in the system.

Let the volume of each vessel be V.

Initially:

Total moles:

n = 2PV / RT

After heating:

Pressure becomes P_f.

Number of moles in first vessel:

n₁ = P_fV / (R × 400)

Number of moles in second vessel:

n₂ = P_fV / (R × 500)

Conservation of moles:

n₁ + n₂ = n

Substituting:

P_f [ 1/400 + 1/500 ] = 180/400

Solving:

P_f = 100 kPa

Final Answer

Option (3) 100 kPa