Enthalpy of Formation for Ideal Gas at 298.15K

• Definition

  Enthalpy of Formation for Ideal Gas at 298.15K is the calorie either absorbed or released when making 1 mol of compound in the ideal gas state from single element substances of each element consisting the molecule at 298.15K.

• Estimation Method

  - MolInstincts: The Property value is estimated by the combination of fundamental thermodynamic theories, modern modeling approaches, QSPR (quantitative structure-property relationships) methods, and ANN (Artificial Neural Network) with over fitting prevention algorithm, utilizing the quantum chemical calculations results and molecular descriptors. The estimated value is finally determined after manual inspection.
  - Joback: Group Contribution Method (Estimation of pure-component properties from group-contributions, Chem.Eng.Commun., 1987. 57. 233)
  - Gani: Group Contribution Method (New Group Contribution Method for Estimating Properties of Pure Compounds, AIChE J., 1994. 5. 1697)

• Supplementary Explanation on Accuracy

  Comment	Meaning of Comment
  ≤ 1 kcal/mol	0 kcal/mol ≤ abs error ≤ 1 kcal/mol
  ≤ 3 kcal/mol	1 kcal/mol < abs error ≤ 3 kcal/mol
  ≤ 5 kcal/mol	3 kcal/mol < abs error ≤ 5 kcal/mol
  ≤ 7 kcal/mol	5 kcal/mol < abs error ≤ 7 kcal/mol
  > 7 kcal/mol	abs error > 7 kcal/mol
  Exp. Data Unavailable	Experimental Data are Unavailable

  Where absolute error means the absolute value of (experimental value)-(calculated value).