Hi! I have two questions. First, how do I calculate the pressure of a non-ideal gas if I know volume, temperature and the number of moles? The gas in question is water vapor. I suspect a constant for the specific gas will be involved. Which constant is this? And secondly, how do I calculate how much energy is stored in a pressurized gas if I know the mass (or the number of moles) and the pressure of the gas? Thanks in advance!