Carbonates, solubility products

Considering pressure, a threshold value is found above which the amount of dissolved C02 and (bi)carbonate, together with the dissolved calcium (determined also by L/S ratio) exceeds the calcium carbonate solubility product, such that precipitation can occur. 

Calculation of Apparent Calcium Carbonate Solubility Products The precise determination of the solubility of calcite... 

Another plausible control on lanthanide solubility in seawater includes the formation of lanthanide carbonates (Choppin 1986, 1989). Previous determinations of lanthanide carbonate solubility products include the works of Jordanov and Havezov (1966) and Firsching and Mohammadzadel (1986). In the former study lanthanide solubility products expressed as Ai p(M)= at 25 C and zero ionic strength, were found to... 

Although the hydroxides of the alkaline earth elements become more soluble in water as we go down the column, the opposite trend is observed in the solubilities of the sulfates and carbonates. For example, Table 21-VII shows the solubility products of the alkaline earth sulfates. 

NOTE The calcium carbonate limit that RO system designers typically require is +1.6 to 1.8 LSI in the concentrate or reject water, and the calcium sulfate design limit typically calls for a maximum reject water saturation ratio of 1.6 to 1.8 times solubility product. 

Almost all the Earth s carbon is found in the lithosphere as carbonate sediments that have precipitated from the oceans. Shells of aquatic animals also contribute CaC03 to the lithosphere. Carbon returns to the hydrosphere as carbonate minerals dissolve in water percolating through the Earth s crust. This process is limited by the solubility products for carbonate salts, so lithospheric carbonates represent a relatively inaccessible storehouse of carbon. 

C18-0074. For the following salts, write a balanced equation showing the solubility equilibrium and write the solubility product expression for each (a) lead(II) chloride (b) magnesium carbonate (c) nickel(II) hydroxide and (d) silver acetate. 

The feasibility of the above reaction ensues from the data on the solubility products of lead sulfate and lead carbonate salts. Evidence abounds that both sulfate and carbonate ions are present. 

Using on-line mass spectroscopy [65] carbon dioxide and formic acid were demonstrated as soluble products of methanol oxidation. The former gives the most intense MS signal according to the fact that it is the main product. There are two main problems to detect formic acid as such. In the presence of carbon dioxide most of the m/e signals of HCOOH overlap with signals of the major product. Besides this, in the presence of methanol, formic acid reacts to form the methyl ester ... 

The insolubility of calcium carbonate is clearly evident from the value of the solubility product, Ksp, in water at 25°C Ksp = 8.7 x 10-9. The carbonate ions are produced in seawater by the dissociation of carbonic acid that forms from the... 

If S moles of CaCC>3 dissolve in a liter of water, then S moles each of calcium ion and carbonate ion form. With these ion concentrations equal to S, the solubility of CaCC>3 is calculated as 9.3 x 10 5 M. The higher solubility of magnesium carbonate in water, 6.3 x 10 3 M, results from the larger solubility product constant. Nevertheless, both of these carbonate salts are rather insoluble, and the excess carbonate anions provided by the sodium carbonate effectively precipitate the calcium and magnesium ions from solution. 

Sugaya et al. demonstrated the activity of Comamonas sp. TKV3-2-1 for quinoline removal. This aerobic strain utilizes quinoline as carbon and nitrogen source and degrades it to water soluble products [319], No enzymes were identified in this study. 

This scheme does not take into account the rate of loss of reduced carbon as buried coal, oil and gas. We do not know either if life could take a form that can exist at higher oxygen levels perhaps at lower temperatures, implying again that the present state of our atmosphere is not the final one. We shall analyse the nature of such steady states in Chapter 3 and return to the problem in Chapter 11. Note that C02 levels in the sea are fixed by the solubility of certain carbonates, and hence by solubility products, the pH of the sea, the C02 in the atmosphere and the temperature. 

Equilibrium with precipitation. The previous example calculated carbonate speciation admitting unrestricted solubility of all species. Actually, it is easily verified that the calculated calcium and carbonate concentrations exceed calcium carbonate solubility as measured by the solubility product... 

Let us add the moles of precipitated calcium carbonate as a sixth variable x6, modify the calcium and carbonate conservation equations f2(x) and /3(x) in order to account for solid phase contribution, and use the expression of the solubility product as a sixth equation. The six equations to be solved read... 

In reviewing the basic solubility products for these systems, the sulfide system removes the most inorganics, with the exception of arsenic, because of the low solubility of sulfide compounds. This increased removal capability is offset by the difficulty in handling the chemicals and the fact that sulfide sludges are susceptible to oxidation to sulfate when exposed to air, resulting in resolubilization of the metals. The carbonate system is a method that relies on the use of soda ash (sodium carbonate) and pH adjustment between 8.2 and 8.5. The carbonate system, although... 

Extraction of the fish showed that 81% of the carbon-14 residues were organosoluble, 13% were polar water-soluble products and 6% unextractable. Chromatography of the organo-soluble radioactivity showed that a large proportion (87%) was still very polar in nature with DDT accounting for 8%, DDE 3% and DDD 2%. 

Write a balanced dissolution equation and solubility product expression for silver carbonate, Ag2C03. 

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