Thermodynamic free energy
The thermodynamic free energy is the amount of work that a thermodynamic system can perform. The concept is useful in the thermodynamics of chemical or thermal processes in engineering and science. The free energy is the internal energy of a system minus the amount of energy that cannot be used to perform work. This unusable energy is given by the entropy of a system multiplied by the temperature of the system.
Like the internal energy, the free energy is a thermodynamic state function. Energy is a generalization of free energy, since energy is the ability to do work which is actually free energy.
Overview
Free energy is that portion of any first-law energy that is available to perform thermodynamic work; i.e., work mediated by thermal energy. Free energy is subject to irreversible loss in the course of such work. Since first-law energy is always conserved, it is evident that free energy is an expendable, second-law kind of energy that can perform work within finite amounts of time. Several free energy functions may be formulated based on system criteria. Free energy functions are Legendre transformations of the internal energy. For processes involving a system at constant pressure p and temperature T, the Gibbs free energy is the most useful because, in addition to subsuming any entropy change due merely to heat, it does the same for the pdV work needed to "make space for additional molecules" produced by various processes. (Hence its utility to solution-phase chemists, including biochemists.) The Helmholtz free energy has a special theoretical importance since it is proportional to the logarithm of the partition function for the canonical ensemble in statistical mechanics. (Hence its utility to physicists; and to gas-phase chemists and engineers, who do not want to ignore pdV work.)
Free energy
Free energy may refer to:
In science:
- Helmholtz free energy (A=U–TS), the energy that can be converted into work at a constant temperature and volume
- Work content, a related concept used in chemistry
- Gibbs free energy (G=H–TS), the energy that can be converted into work at a constant temperature and pressure throughout a system
- Work content, a related concept used in chemistry
In economics:
Perpetual motion
A perpetual motion is a motion of enduring physical objects that are very large compared with atoms, that continues indefinitely. This is impossible because of friction and other modes of degradation or disruption of form. A perpetual motion machine is a hypothetical machine that can do work indefinitely without an energy source. This kind of machine is impossible, as it would violate the first or second law of thermodynamics.
These laws of thermodynamics apply even at very grand scales. For example, the motions and rotations of celestial bodies such as planets may appear perpetual, but are actually subject to many processes that degrade or disrupt their form, such as solar winds, interstellar medium resistance, gravitation, thermal radiation and electromagnetic radiation.
Thus, machines which extract energy from finite sources will not operate indefinitely, because they are driven by the energy stored in the source, which will eventually be exhausted. A common example is devices powered by ocean currents, whose energy is ultimately derived from the Sun, which itself will eventually burn out. Machines powered by more obscure sources have been proposed, but are subject to the same inescapable laws, and will eventually wind down.
Free Energy (band)
HIDDEN ERROR: Usage of "Associated_Acts" is not recognized
Free Energy is an American rock band based out of Philadelphia, Pennsylvania. The members include Scott Wells, Paul Sprangers, Evan Wells, and Nicholas Shuminsky.
History
The Wells brothers and Sprangers are originally from Red Wing, Minnesota, where they first started playing together in the now-defunct hard-core, emo rock band, Hockey Night. Shuminsky, of St. Paul's Superhopper and Malachi Constant, joined Sprangers and the Wells brothers to form the band in the Fall of 2008. Critics have compared Free Energy's sound to 1970s rock acts like Journey and The Cars. The band rose to national prominence in March 2010 with the critically acclaimed release of their debut album Stuck on Nothing, produced by James Murphy of LCD Soundsystem. On March 17, Rolling Stone named Free Energy one of the best new bands of 2010. The band has also received high marks from Spin Magazine, who called their work "excellent". On March 17th, 2010 the band performed on the Late Show with David Letterman. The single Bang Pop was used on the Pilot episode of sitcom Raising Hope. Free Energy toured heavily with Mates of State, Titus Andronicus, Hollerado, Foreign Born and The Postelles. They opened for Weezer during their Memories tour and performed on the Weezer Cruise in January 2012.
Podcasts:
