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.