Calcium original weight

Some of the metallic constituents were somewhat soluble in the propane-oil portion, but all tended to be concentrated in the asphaltic portion. Although vanadium (0.02% by weight in the original crude petroleum) was present in all fractions, the greater part was found in the cyclohexane and benzene fractions. From the similarity of the absorption spectra of the vanadium concentrates from petroleum and those of synthetic vanadium porphyrin complexes, Skinner arrived at the conclusion that vanadium compounds from the petroleum of the Santa Maria Valley Field in California exist as porphyrin complexes. Additional metallic constituents were detected by Skinner as these became concentrated in the various solvent fractions, including aluminum, titanium, calcium, and molybdenum. 

Calcium carbonate (calcite, CaC03) is calcined to lime (CaO) during high-temperature ashing, and carbon dioxide is evolved, resulting in a 44% reduction in weight from the original calcite ... 

Figure 4.15. A plot of weight % calcium carbonate versus percent original calcium carbonate dissolved. For sediments of high initial calcium carbonate content, little change in weight % takes place until approximately 50 percent of the carbonate has dissolved. Small variations in initial calcium carbonate concentration can lead to large variations in calcium carbonate concentration at high dissolution values. (After Morse, 1973.)...

What a powerful weapon could be forged by a clear scientific explanation of the apparent inconsistencies of Prout s theory. Pregnant doubts and questions had already been raised. Crookes, in 1886, addressing the British Association at Birmingham, had made a bold and original statement. I conceive that when we say the atomic weight of calcium is 40, we really explain the fact, while the majority of calcium atoms have an actual atomic weight of 40, there are not a few which are represented by 39 or 41, a less number by 38 or 42, and so on. ... 

The internal standard method has been widely used for the measurement of the quartz content of industrial dusts. In this analysis, fluorite (CaFj) has been found to be a suitable internal standard. Figure 14-5 shows a calibration curve prepared from mixtures of quartz and calcium carbonate, of known composition, each mixed with enough fluorite to make the weight fraction of fluorite in each composite sample equal to 0.20. The curve is linear and through the origin, as predicted by Eq. (14-16). Bumsted [14.25] describes the determination of quartz in dust by this method, with particular attention to the problems posed by very small samples. 

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