1. The problem statement, all variables and given/known data Hello, Everyone! So I recently did an experiment in which I pressurised a vessel and then allowed some of the air to move into a smaller vessel and wait for the pressures to stabilise. I then calculated the Cp/Cv ratio and it was slightly lower than the expected 1.40. I am wondering what would cause the value to be lower 2. Relevant equations 3. The attempt at a solution For a start I think that the equipment was a bit leaky, which would make me think that the pressure would drop so the value of Cp would be smaller, lowering the ratio. I'm a bit stuck for any others, can anyone lend a hand? Thanks!