Bibliography #519,905

Reference Label	Details
Gunther 1932	P. Günther, E. Wassmuth, and L. A. Schryver, Z. phys. Chem. A 158, 297-304 (1932) Die Bildungswärme des Ozons
note O3	Gunther 1932 give 34.22 +- 0.24 kcal/mol at constant volume and 33.93 kcal/mol at constant pressure. This originates by taking {CO } + 1/2 {O2 } -> {CO2 } DH = 67.70 kcal/mol at constant pressure, or 67.70 - 0.29 = 67.41 kcal/mol at constant volume (NB: 0.29 kcal/mol = 1/2kT). Gunther finds that at constant volume DH(O3) = DH(CO + 1/2 O2 -> CO2) *[Vol(CO)/Vol(O3)]. The ratio of volumes has been found to be 6.245/12.30 = 0.5077, producing DH(O3) = 34.22 kcal/mol at const volume or 34.22 - 0.29 = 33.93 at constant pressure. using DH(CO + 1/2 O2 -> CO2) = (-)67.62 kcal/mol, the same math produces 33.89 +- 0.24 kcal/mol. Gurvich TPIS must have obtained a similar interpretation of Gunther 1932, because they quote the value as 141.8 +- 2.0 kJ/mol (33.89 +- 0.48 kcal/mol) at 298.15 K. Similarly, JANAF 3 reports this as 33.89 +- 0.36 kcal/mol, but assumes that the temperature (unstated in Gunther 1932) was 18 deg C.

Reference Label

Details

Gunther 1932

P. Günther, E. Wassmuth, and L. A. Schryver, Z. phys. Chem. A 158, 297-304 (1932)
Die Bildungswärme des Ozons

note O3

Gunther 1932 give 34.22 +- 0.24 kcal/mol at constant volume and 33.93 kcal/mol at constant pressure. This originates by taking {CO } + 1/2 {O2 } -> {CO2 } DH = 67.70 kcal/mol at constant pressure, or 67.70 - 0.29 = 67.41 kcal/mol at constant volume (NB: 0.29 kcal/mol = 1/2kT). Gunther finds that at constant volume DH(O3) = DH(CO + 1/2 O2 -> CO2) *[Vol(CO)/Vol(O3)]. The ratio of volumes has been found to be 6.245/12.30 = 0.5077, producing DH(O3) = 34.22 kcal/mol at const volume or 34.22 - 0.29 = 33.93 at constant pressure. using DH(CO + 1/2 O2 -> CO2) = (-)67.62 kcal/mol, the same math produces 33.89 +- 0.24 kcal/mol. Gurvich TPIS must have obtained a similar interpretation of Gunther 1932, because they quote the value as 141.8 +- 2.0 kJ/mol (33.89 +- 0.48 kcal/mol) at 298.15 K. Similarly, JANAF 3 reports this as 33.89 +- 0.36 kcal/mol, but assumes that the temperature (unstated in Gunther 1932) was 18 deg C.