Gas Constant: (also known as the universal gas constant) is symbolized by R and has a value of 8.314 472 ± 0.000 015 J/mol·K (for all purposes in this material, R = 8.314 J/mol·K).
Geosynchronous: an orbit where a satellite remains above the same point on the planet, because the velocity of the satellite, and the rotational velocity of the planet are the same. For Earth, a satellite at 35,785 kilometers above the equator will be geosynchronous. This is the orbit used for communications satellites, so that the ground based transmitter/receiver always points to the same location in the sky. At their extremely high altitude, geosynchronous sattleites can "see" about one third of the Earth's surface
Gibbs free energy: the maximum possible work that can be obtained from a system. Symbolized by G, the absolute free energy of any system is impossible to measure. However changes in free energy, DG, can be calculated from tabulated free energies using the relationship:
DG = DH - TDS for a system at constant temperature. Reactions that occur spontaneously have negative DG. A reaction at equilibrium has DG = 0.