Question

An insulated rigid vessel is divided into two parts by a membrane. One part of the vessel contains air at 10 Mpa and other part is fully evacuated. The membrane ruptures and the air fills the entire vessel. Is there any heat and / or work transfer during this process? Justify your answer. 

Answer 1

For rigid vessel and unrestrained expansion

Change in volume dV = 0

Work transfer. W =  pdV = 0

For insulated vessel, heat transfer, Q = 0

According to the first law of thermodynamics the sum of work transfer is equal to the sum of heat transfer.

Therefore W = Q = 0