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Index (G)

GA - GC

GD - GF

GG - GJ

GK - GN

GO - GR

GS - GV

GW - GZ

Moment of truth
More than 25 million people died in Europe from the bubonic plague (the black death) in five years, from 1347 to 1352.


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Gibb's free energy Chem.
Thermodynamic free energy (G) at constant pressure, defined as: G = H - TS where H is the enthalpy change the involves the change of energy at the surroundings and S is the entropy change relates to the chemical system. T is the temperature of the system. The G therefore determines the spontaneity of a chemical reaction involving both the chemical system and its surroundings. If G is a positive number, then the chemical reaction is not spontaneous. If G is negative, then the reaction is spontaneous. If G=0 then the chemical reaction is in equilibrium. It is named after the US chemist J. W. Gibbs (1839-1903).

gibbsite Min.
A mineral form of the hydrated aluminium hydroxide. It is an important component of bauxite rock where aluminium is obtained. It is easily cleaved in sheets (basal) and appear translucent white with shades of grey, blue and green. It is rather soft with hardness of 3.5 and belongs to monoclinic crystal system. The growth habit often in the form of glattened tabular crystal. Gibbsite is named after the US mineral collector George Gibbs (1776-1833).

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