Standard Energy Change of Formation
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 that substance from its component elements, at their standard states (the most stable form of the element at 25 degrees Celsius and 100 kilopascals). Its symbol is ΔfG˚.
All elements in their standard states (oxygen gas, graphite, etc.) have 0 standard Gibbs free energy change of formation, as there is no change involved.
- ΔrG = ΔrG˚ + RT ln Qr; Qr is the reaction quotient.
At equilibrium, ΔrG = 0 and Qr = K so the equation becomes ΔrG˚ = −RT ln K; K is the equilibrium constant.
Read more about this topic: Gibbs Free Energy
Famous quotes containing the words standard, energy, change and/or formation:
“As long as male behavior is taken to be the norm, there can be no serious questioning of male traits and behavior. A norm is by definition a standard for judging; it is not itself subject to judgment.”
—Myriam Miedzian, U.S. author. Boys Will Be Boys, ch. 1 (1991)
“I have witnessed the tremendous energy of the masses. On this foundation it is possible to accomplish any task whatsoever.”
—Mao Zedong (1893–1976)
“But let it pass, and think it is of kind
That often change doth please a woman’s mind.”
—Sir Thomas Wyatt (1503?–1542)
“Out of my discomforts, which were small enough, grew one thing for which I have all my life been grateful—the formation of fixed habits of work.”
—Elizabeth Stuart Phelps (1844–1911)