L01_04_Sept_2013_Intro

Acad sci usa vol 77 pp 6973 6977 note that there were

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Unformatted text preview: par00oning of salt into liquid phase A slightly more complex system for example, a chemical plas0cs plant • par0cipa0ng chemical species: a complex array of organic compounds • numerous possible reac0ons and end products • physics is important at this scale: fluid flow, mixing, density segrega0on • advanced materials necessary to ‘contain’ the system • constant supply of material and energy required to keep the system ac0ve Earth as a giant chemical system Star0ng materials: 5.9 x 1024 kg mixture of all 92 naturally- occurring elements** some elements important for biology: main players (by mole frac0on): C 446 ppm Fe 32.07% N 4.1 ppm O 30.12% H 33 ppm Si 15.12% P 1920 ppm Mg 13.90% K 135 ppm S 2.92% Ni 1.82% others of interest: Ca 1.54% Au 257 ppb Al 1.41% Pt 167 ppm U 14.3 ppb source: Morgan JW & Anders E (1980) Chemical composi0on of Earth, Venus, and Mercury Proc. Natl. Acad. Sci. USA vol. 77, pp. 6973- 6977 **note that there were actually more than 92 elements. There were several other ‘short lived’ radioac0ve nuclides formed during precursor supernovae. These have long- since decayed away (are ex0nct), but some have le` as evidence unique stable daughter atoms. Earth as a giant chemical system • The system is ‘contained’ by gravity • gravity provides an extremely effec0ve ‘seal’ • only H escapes in appreciable quan00es • The system is so large that physics becomes extremely important • early segrega0on of core and mantle • plate tectonics • fluid dynamics of ocean and atmosphere • The system has been ‘reac0ng’ for the past 4.56 billion years! Ear...
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This document was uploaded on 03/26/2014 for the course GEC AS.270.103 at Johns Hopkins.

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