Oxygen/carbon elemental ratios

Bertram AK, Martin ST, Hanna SJ, Smith ML, Bodsworth A, Chen Q, Kuwata M, Liu A, You Y, Zorn SR (2011) Predicting the relative humidities of liquid-liquid phase separation, efflorescence, and deliquescence of mixed particles of ammonium sulfate, organic material, and water using the organic-to-sulfate mass ratio of the particle and the oxygen-to-carbon elemental ratio of the organic component. Atmos Chem Phys 11 10995-11006... 

In recent years, tremendous progress has been achieved in the analysis of the isotope composition of important trace compounds in the atmosphere. The major elements - nitrogen, oxygen, carbon - continually break apart and recombine in a multitude of photochemical reactions, which have the potential to produce isotope fractionations (Kaye 1987). Isotope analysis is increasingly employed in studies of the cycles of atmospheric trace gases e.g., CH4 and N2O, which can give insights into sources and sinks and transport processes of these compounds. The rationale is that various sources have characteristic isotope ratios and that sink processes are accompanied by isotope fractionation. 

Third, carbon, nitrogen, and oxygen, the elements that catalyze hydrogen burning in the Sun, are relatively abundant in the solar system. Oxygen is somewhat more abundant than carbon the C/O ratio is 0.54. Because CO is a very stable molecule, most of the carbon and oxygen in the early solar system was tied up in CO. The excess oxygen that remained controlled the chemical environment of the early solar system. 

Carbon is the fourth most abundant element in the universe. Its abundance in the Sun is about one-half that of oxygen, butreveals differing ratios to oxygen in other stars and in nebulae. The most abundant isotope of carbon, 12C, is the fourth most abundant nucleus in the universe. The two most abundant, 2H and 4He, are remnants of the Big Bang, whereas l60, the third most abundant, and 12C are created during the evolution of stars. Carbon ranks therefore as one of the great successes of stellar nucleosynthesis. The evolution of stars makes evident why this is so. From the isotopic decomposition of normal carbon one finds that the mass-12 isotope, 12C, is 98.9% of all C isotopes. 

Fig. 9. Composition changes of catalyst D3001 with days of synthesis with IH2 + ICO gas at 7.8 atmosphere in test X218. Part A presents atom ratios of nitrogen, total carbon, elemental carbon, and oxygen to iron. Part B shows the distribution of iron as carbonitride and magnetite. Part C presents the temperatures of synthesis. Reprinted by permission of the American Chemical Society.

Major results Figure 14.35 shows the correlation between IR peak area and difference of XPS peak area. The IR peak area is at 1720 cm, and the XPS peak area difference is at 288.4 eV. Both peaks were assigned to C=O. The results obtained by the two methods show a good correlation. Figure 6.7 shows the effect of treatment time by oxygen plasma of carbon fiber on the 0/C elemental ratio vs. treatment time. A plateau is reached after a short period of treatment. 

Why do marathon runners eat large amounts of pasta the day before a big race Foods such as pasta, bread, and fruit are rich in carbohydrates. A carbohydrate is an organic molecule that contains the elements carbon, hydrogen, and oxygen in a ratio of about two hydrogen atoms and one oxygen atom for every carbon atom. Early chemists thought that carbohydrates were chains of carbon with water attached—hydrated carbon— which is how carbohydrates were named. Chemists now know that carbohydrates are not hydrated carbon chains, but the name persists. 

A generally positive covariation between 6 0 and S C is apparent across the data set as a whole (Fig. 10). However, covariations between 6 0 and 6 C and other parameters, e.g. carbonate content, trace element content or trace element ratios, are absent or very weak. Oxygen isotopic values for both early calcite and early dolomite, combined with temperature constraints inferred from IGVs, are consistent with precipitation from mostly 0-depleted fluids (Fig. 11). Ferroan dolomite and late... 

Diagenetic carbonates were analysed for strontium, oxygen and carbon isotope ratios and for rare earth elements (REEs). Pure siderite was obtained by a combination of heavy liquid segregation and magnetic separation, whereas pure ankerite was handpicked under a binocular microscope. Calcite was dissolved from whole-rock powders using dilute acid solutions (see below). 

The experimentally determined carbon-hydrogen ratios varied from 1.02 to 1.05 for the many polymer samples studied. Thus, the elemental composition is the same as in the starting benzene (ignoring the chemisorbed oxygen in some samples). 

The elemental ratio of carbon to tin and of oxygen to tin were influenced less by these parameters. It has been reported in an earlier paper(8) that oxygen to tin and carbon to tin ratios on a series of samples gave reproducible results (variation of +8%). Hence it was decided in this study to use the elemental ratios of carbon to tin and oxygen to tin for characterisation of film. 

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