Quantitative composition of compounds

These black pearls are made of layers of calcium carbonate. They can be measured by counting or weighing. 

6 Calculating the Molecular Formula from the Empirical Formula 

The composition of compounds is an important concept in chemistry. Determining numerical relationships among the elements in compounds and measuring exact quantities of particles are fundamental tasks that chemists routinely perform in their daily work. 

---

Quantitative Composition of Compounds 121 Introduction to Organic Chemistry 466... 

Optimization of the qualitative and quantitative composition of compound mixtures with the aim of achieving the maximum pharmacological effect ... 

Impulse for the valuation of the chamomile collection has become if the identification of four chemical types of this plant species different by the qualitative -quantitative composition of chemical compounds in the essential oil was carried out by Schilcher in 1987 (Table 7.6). This veiy important fact was referred to chamomile biodiversity. This biodiversity was created during long time process (evolution) inregardtoinfluenceofeco-physiological conditions (biotic-andabiotic-factors) on the concrete place of chamomile population growth. 

Sawicki, E., S. P. McPherson, T. W. Stanley, J. Meeker, and W. C. Elbert. Quantitative composition of the urban atmosphere in terms of polynuclear aza heterocyclic compounds and aliphatic and polynuclear aromatic hydrocarbons. Int. J. Air Water Pollut. 9 515-524, 1%5. 

In its narrow sense, chemical analysis is an activity of obtaining information on the identity or on the quantitative composition of a sample. By chemical analysis an analytical result is produced, which may be one or more numbers, or one or more compound names. Why do analysts, or in general analytical laboratories, produce these numbers and names This question has been addressed by several analytical chemists... 

Milk is secreted by all species of mammals to supply nutrition and immunological protection to the young. It performs these functions with a large array of distinctive compounds. Interspecies differences in the quantitative composition of milk (Jenness and Sloan 1970) probably reflect differences in the metabolic processes of the lactating mother and in the nutritive requirements of the suckling young. 

Use of GLC to determine qualitative and quantitative composition of volatile compounds in citrus oils has become common. However, there are many discrepancies in the literature concerning the quantitative composition of citrus oils. Analyses of volatile aldehydes are of major importance, because composition and quantity of these compounds influence the quality and value of citrus oils. Compositional differences between... 

Najda, A. and Dyduch, J. (2004) Determination of quantitative composition of polyphenolic compounds occurring in leaf stalks of three celery cultivars (Apium graveolens L. var. dulce Mill./Pers.). Folia Universitatis Agriculturae Stetinensis, Agricultura 95, 259-264. 

The discovery of the compound nature of water by Cavendish and Watt, and the results obtained by Lavoisier and his coadjutors in their investigations of the quantitative composition of this substance, rendered the phlogiston theory untenable. It had played a useful part as the first step to placing the science of chemistry on a rational basis, and it is interesting to note that both Priestley and Cavendish remained phlogistians to the end. 

According to current clinical practice, only a small part of the information obtained from examination of tissues and biological fluids is used. For disorders of metabolic pathways, reflected in the qualitative and quantitative composition of metabolites of endogenous compounds, analysis of the results of these examinations can be the basis for verification of hypotheses on the causes of such diseases. 

Adsorption processes at natural phase boundaries occur from the aqueous phase containing complex mixtures of different organic and inorganic compounds and they are not in equilibrium. Adsorption behavior of organic molecules can be described by competitive adsorption of the mixture, in which very often less adsorbable materials are present at higher concentrations and strongly adsorbable substances are present at lower concentrations. Since the adsorption process depends on both the adsorption constant and the adsorption kinetics, which include the mass transfer of adsorbable molecules from the bulk phase toward the surface as well as the intrinsic rate of attachment to the surface, the adsorption layer formed is influenced by qualitative and quantitative composition of the complex mixture of adsorbable solutes. 

---