note COf | Smith 1946 examined at 800 and 1000 deg C the equilibria 2 H2 + C -> CH4 and C + CO2 -> 2 CO. For each temperature there are two determinations: by direct measurement and by extrapolation of the equilibrium with austenite. The fitted data produce for 1165 K DeltaG of 37.521 +- 0.068 kJ/mol and -33.545 +- 0.058 kJ/mol, where the uncertainty reflects 95% confidence limit derived from std. dev. for the fitted values. For the latter equilibrium, CODATA extracts a third-law value of 172.13 +- 0.40 kJ/mol. The present value DeltaG1165 = -33.545 +- 0.058 kJ/mol extrapolates to 172.408 +- 0.058 kJ/mol. |