Atomic weight of cadmium

To prepare a calibration solution of 1 pmol L 1 ofCd+2 from a CRM of pure Cd metal, a mass of Cd is weighed into a flask, dissolved, and made up to the mark. The atomic weight of cadmium is 112.411 g mol 1 with uc = 0.008 g mol 1. Thus, 1.12411 g of pure cadmium metal dissolved in hydrochloric acid and made up to 1.00 L will have an amount concentration of 1.00 x 10 2 mol L 1. An aliquot of 0.100 mL of this solution made up to 1.00 L should create the desired solution of amount concentration 1.00 pmol Lr1. Until a proper estimate of the measurement uncertainty is made the significant fig-... 

EXAMPLE 26-2 The following values were obtained for the atomic weight of cadmium 112.25, 112.36, 112.32, 112.21, 112.30, 112.36. Does the mean of these values (112.30) differ significantly from the accepted value 112.40 ... 

Cadmium is a transition metal in group IIB of the periodic table of elements. The metal is bluish-white to silver-white. At room temperature, it has a hexagonal close-packed crystal structure. Eight stable isotopes are known to be present in natui . The atomic weight of cadmium is 112.4 and the atomic number 48. The density at 25°C is 8.6 g/cm the melting point 321°C and the boiling point 765°C. The most common oxidation state is +2. " The most important compounds are cadmium acetate, cadmium sulfide, cadmium sulfoselenide, cadmium stearate, cadmium oxide, cadmium carbonate, cadmium sulfate, and cadmium chloride. The acetate, chloride, and sulfate are soluble in water, whereas the oxide and sulfide are almost insoluble. ... 

Cadmium is a silver-white, blue-tinged, lustrous metal that melts at 321°C and boils at 767°C. This divalent element has an atomic weight of 112.4, an atomic number of 48, and a density of 8.642 g/cm3. It is insoluble in water, although its chloride and sulfate salts are freely soluble (Windholz et al. 1976 USPHS 1993). The availability of cadmium to living organisms from their immediate physical and chemical environs depends on numerous factors, including adsorption and desorption rates of cadmium from terrigenous materials, pH, Eh, chemical speciation, and many... 

A 1.5276-g sample of CdC underwent an electrolytic process separating all of the cadmium from the sample. The weight of the metallic cadmium was 0.9367 g. If the atomic mass of chlorine is taken as 35.453, what must be the atomic mass of cadmium from this experiment ... 

Cadmium has an atomic number of 48, an atomic weight of 112.40 consisting of eight... 

Cadmium is a silver-white metal with an atomic weight of 112.4 and a low melting point of 321 °C. It is malleable and can be rolled out into sheets. The metal unites with the majority of the heavy metals to form alloys. It is readily oxidized to the +2 oxidation state, giving the colorless Cd2+ ion. Cadmium persists in the environment its biological half-life is 10 to 25 years. 

The atomic weight being, in mostof the above instances, equal to the vapor density, and to half the molecular weight, it may be inferred that the molecules of these elements consist of two atoms. Noticeable discrepancies exist in the case of four elements. The molecular weights of phosphorus and arsenic, as obtained from their vapor densities, are not double, but four times as great as their atomic weights. The molecules of phosphorus and arsenic are, therefore, supposed to contain four atoms. Those of cadmium and mercury contain but one atom. 

This is where Mendeleev is possibly trying to decide which elements to discuss after the alkali metals in his book. It could either be zinc and cadmium or the alkaline earth elements, or perhaps even both together as shown in the fragment periodic table above. In fact, this fragment may represent the first time that a horizontal comparison of the atomic weights of elements had been consciously carried out."... 

In some cases, Mendeleev would correct the atomic weights of a misplaced element, but there were also cases where he considered it sufficient to move an element in order to reflect more faithfully certain family resemblances, without changing the atomic weight in question. This is what he did with mercury, which he came to regard as an analogue of zinc and cadmium rather than of copper and silver, as he had done in his earliest tables. ... 

Cadmium vapor is a toxic substance whose diffusivity in air is not readily available in the literature. It is desired to calculate its diffusivity at its boiling point of 1038 K and a pressure of 1 atm. Because an empirical atomic volume is not available, we use the reported value for its liquid volume of 14 cm / mol for an atomic weight of 112.4. We obtain, using Equation 3.2 ... 

Each element is made up of very small entities called atoms all atoms of the same element behave identically chemically. The study of chemistry, therefore, can logically begin with elements and the atoms of which they are composed. Each element is designated by an atomic number, a name, and a chemical symbol, such as carbon, C potassium, K (for its Latin name kalium) or cadmium, Cd. Each element has a characteristic atomic mass (atomic weight), which is the average mass of all atoms of the element. 

The uptake of aluminum, cadmium, chromium, cobalt, cop-per, iron, lead, magnesium, manganese, molybdenum, nickel, silver, tin, and zinc by B. subtilis Strain 168 is reported. These data were obtained during the lag phase, exponential phase, stationary phase, and the sporulation phase of the maturation cycle of this bacterial strain. Nonflame atomic absorption spectrometry was the method of analysis for all the metals except calcium, which was determined by flame atomic absorption spectrometry. The complete microbiological and analytical procedures are described. Uptake curves as a function of moles per cell, of moles per dry weight of a cell, and of percent available are reported. The data show that these metals seem to be required for growth. No attempts were made to postulate the roles played by these metals. 

Subsequent studies90 focused on the population structure of fish presenting tumors as well as the role of heavy metals. Overall neoplasm prevalence appears to be stable at about 22% of the population. No juvenile fish, out of 2000 + examined, exhibited tumors. Likewise, tumor prevalence did not appear to be seasonal or site specific within the Lake of the Arbuckles. Water, sediment and fish tissues were collected from the Lake of the Arbuckles, a reference lake outside the drainage, and were analyzed for total recoverable metals (cadmium, chromium, copper, nickel and lead) by graphite furnace atomic absorption. Chromium, copper and nickel were found in the water samples at concentrations of > 1 — 8.6 /xg/1. Low concentrations (>1-13.6 /xg/g wet weight) of all the metals were found in the sediment and liver tissues from both sites. Based on these concentrations, heavy metal contamination does not appear linked to neoplasm occurrence. 

Atomic weight < >112. Molecular weight 112. Molecular and atomic ooUuaem. 1 litre ef cadmium vapour weight 56 crithe. Sp.gr. 81. Eusec below 260°. Eamtg volatile, Atomieitg ". Evidence of atomicity t—... 

Fig. 4.5.6. An example of the combination of gel permeation (ion exchange) chromatography of metalloproteins with atomic absorption spectrometry for evaluation of fractions I96], Rat liver supernatant (0.2 ml) obtained after injection of cadmium chloride was applied to a TSK Gel SW 3000 column 600x21.5 mm, and eluted with 50 mM Tris-HCl buffer solution (pH 8.6 at 25°C). Absorbance at 280 nm (lower curves) and concentration of cadmium (A) or zinc (B) (upper curves) were continuously monitored. I and II indicate metallothionein-l and -II, respectively. This chromatogram indicates the contribution of ion exchange to TSK Gel SW gel-permeation chromatography, because both separated proteins have the same molecular weight, and the sequence of peaks emerging corresponds to the ion exchange chromatography separation.

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