What is the molar volume of gas at S.T.P. (standard temperature and pressure) and S.A.T.P.(standard ambient temperature and pressure)? I googled the one for S.T.P. and found it to be 24.414L for 1 atm standard pressure, but whereas in Wikipedia it is mentioned that IUPAC recommended the standard pressure to be 100kPa at S.T.P., most websites refer to 1 atm as the standard pressure. The one for S.A.T.P. is more elusive and different websites give different conditions and molar gas volumes. Any help, or reference to threads, websites, etc, is welcome.