27 Jan
2015
27 Jan
'15
1:27 a.m.
A quick calculation of decrease in pressure caused by decrease in temperature... Assumptions: (1) volume unchanged [rigid container] (2) sealed container (3) initial pressure 12.5 psi at 24C, 100% humidity air (4) except for H2O component, assume ideal gas (5) final pressure calculated at 6C (6) pressures above are relative to atmospheric pressure, 14.7 psi Calculation: partial pressure of H2O at 24C is .433 psi; partial pressure of remaining gas is thus 26.77 psi partial pressure of H2O at 6C is .135 psi; partial pressure of remaining gas is 279/297*26.77psi = 25.15psi Total pressure at 6C is then 25.15+.135 psi = 25.29 psi (10.6 psi relative to atmospheric pressure)