Standard Heats and Free Energies of Formation and Absolute Entropies of Elements and Inorganic Compounds. Fe(s), 0, 0, 27.2. FeO(s), -266.5, -244.3, 54. Fe2O3(s), -822.2, -741, 90. Ni(s), 0, 0, 30.1. NiCl2.6H2O(s), -2103.3, -1713.3, 344.3. Standard Gibbs free energies of formation are normally found directly from tables. Once the values for all the reactants and products are known, the standard Gibbs free energy change for the reaction is found by Eq 4-7. Now we can plug in these values we’ve calculated into the free energy equation.
Gibbs Free Energy is a state function, just as enthalpy and entropy are. This means that the DG of the sum of a series of reactions is equal to the sum of the DG’s of the individual reactions: C(s) + 1/2 O2 CO(g) DG -137. The standard Gibbs Free Energy is calculated using the free energy of formation of each component of a reaction at standard pressure. This is a Gibbs free energy graph by Josiah Willard Gibbs. it shows a plane perpendicular to the axis of v (volume) and passing through point A – represents the initial state of the body.
Free energy is a state function, like enthalpy. We can tabulate standard free energies of formation for substances, just as we can tabulate standard enthalpies of formation. It is important to remember that standard values for these functions imply a particular set of conditions, or standard states. The standard Gibbs free energy of formation of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298. This table includes several Standard Gibbs function of formation evaluated at 298 K. Note that all values are in kJ/mol. The standard Gibbs free energy of formation of a compound is the change of Gibbs free energy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states.