http://chemistry.forumotion.com/other-science-f4/-t1.htm Physics, biology, etc. Fri, 18 Sep 2009 07:13:59 GMT 10 http://i75.servimg.com/u/f75/13/25/02/55/extend14.jpg http://chemistry.forumotion.com/other-science-f4/-t1.htm http://chemistry.forumotion.com/other-science-f4/petroleum-chemistry-neftekhimiya-t220.htm rishi777 Petroleum Chemistry (Neftekhimiya), founded in 1961, offers original papers on and reviews of theoretical and experimental studies concerned with current problems of petroleum chemistry and processing such as chemical composition of crude oils and natural gas liquids; petroleum refining (cracking, hydrocracking, and catalytic reforming); catalysts for petrochemical processes (hydrogenation, isomerization, oxidation, hydroformylation, etc.); activation and catalytic transformation of hydrocarbons ... Other Science Fri, 18 Sep 2009 07:13:59 GMT http://chemistry.forumotion.com/other-science-f4/petroleum-chemistry-neftekhimiya-t220.htm#521 http://chemistry.forumotion.com/other-science-f4/petroleum-chemistry-neftekhimiya-t220.htm http://chemistry.forumotion.com/other-science-f4/temperature-time-and-pressure-t219.htm rishi777 It is commonly assumed that petroleum formation is a function of the increasing burial of the source rock. However, other factors than the burial history; such as the type of originating kerogen, and the geothermal gradient are also important. "Kerogen" refers to the organic component of source rock. It began as living organisms, became sediments (comparable to top soil), and then, as they were overlaid, began the change from sediment to sedimentary rock (a process known as ... Other Science Fri, 18 Sep 2009 07:11:14 GMT http://chemistry.forumotion.com/other-science-f4/temperature-time-and-pressure-t219.htm#520 http://chemistry.forumotion.com/other-science-f4/temperature-time-and-pressure-t219.htm http://chemistry.forumotion.com/other-science-f4/petrochemicals-adventure-t218.htm rishi777 The smallest unit of a substance, which still retains the characteristics of that substance, is called a molecule. Molecules can only be divided into atoms - which are different elements. For example, all molecules of water are identical and have the characteristics of water. Two atoms of hydrogen and an atom of oxygen (which made up the molecule) on their own have none of the characteristics of water. Crude oils are mixtures of many different substances, often difficult to separate, ... Other Science Fri, 18 Sep 2009 07:08:07 GMT http://chemistry.forumotion.com/other-science-f4/petrochemicals-adventure-t218.htm#519 http://chemistry.forumotion.com/other-science-f4/petrochemicals-adventure-t218.htm http://chemistry.forumotion.com/other-science-f4/chemicology-t217.htm rishi777 Peroxides have been used in tooth whitening for more than 100 years. Current peroxide-containing whiteners can be classified into three categories: (1) those containing high concentrations of peroxides for professional use only; (2) materials dispensed by dentists and used by patients at home; and (3) over-the-counter products available directly to consumers for home use. Hydrogen peroxide (H2O2) and carbamide peroxide are the most commonly used active ingredients in these whiteners. Both peroxides ... Other Science Fri, 18 Sep 2009 07:03:41 GMT http://chemistry.forumotion.com/other-science-f4/chemicology-t217.htm#518 http://chemistry.forumotion.com/other-science-f4/chemicology-t217.htm