Solubility product for

The thermodynamic solubility product for Pbl2 is determined in this experiment by measuring its solubility at several ionic strengths. 

Solubility can often be decreased by using a nonaqueous solvent. A precipitate s solubility is generally greater in aqueous solutions because of the ability of water molecules to stabilize ions through solvation. The poorer solvating ability of nonaqueous solvents, even those that are polar, leads to a smaller solubility product. For example, PbS04 has a Ks of 1.6 X 10 in H2O, whereas in a 50 50 mixture of H20/ethanol the Ks at 2.6 X 10 is four orders of magnitude smaller. 

Potentiometric electrodes are divided into two classes metallic electrodes and membrane electrodes. The smaller of these classes are the metallic electrodes. Electrodes of the first kind respond to the concentration of their cation in solution thus the potential of an Ag wire is determined by the concentration of Ag+ in solution. When another species is present in solution and in equilibrium with the metal ion, then the electrode s potential will respond to the concentration of that ion. Eor example, an Ag wire in contact with a solution of Ck will respond to the concentration of Ck since the relative concentrations of Ag+ and Ck are fixed by the solubility product for AgCl. Such electrodes are called electrodes of the second kind. 

Solubility equilibrium constants, such as (20) and (22), are given a special name—the solubility product. It is symbolized K,p. A low value of K,p means the concentrations of ions are low at equilibrium. Hence the solubility must be low. Table 10-11 lists solubility products for some common compounds. 

For sparingly soluble salts (i.e. those of which the solubility is less than 0.01 mol per L) it is an experimental fact that the mass action product of the concentrations of the ions is a constant at constant temperature. This product Ks is termed the solubility product . For a binary electrolyte ... 

The free concentration of Plutonium, [Pu +], is controlled by either solubility products, for Pu02 or Kgp for Pu(0H)2C03,... 

The equilibrium constant for the solubility equilibrium between an ionic solid and its dissolved ions is called the solubility product, Ksp, of the solute. For example, the solubility product for bismuth sulfide, Bi2S3, is defined as... 

The compound Cr(OH), is very insoluble in water therefore, electrochemical methods must be used to determine its fCsp. Given that the reduction of Cr(OH)3(s) to Cr(s) and hydroxide ions has a standard potential of —1.34 V, calculate the solubility product for Cr(OH)3. 

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. 

C18-0097. The solubility product for pbCl2 is 2x10. If 0.50 g of solid pbCl2 is added to 300 mL of water, will all the solid dissolve ... 

The concentration products obtained in the experiment by Shikazono (1994) can be compared with the solubility product for large well-formed polyhedral barite crystals... 

Figure 1.55. The relationships between the concentration product, (Ba " )i(S04 )i, at the initiation of barite precipitation, and morphologies of barite crystals (Shikazono, 1994). The dashed line represents the boundary between dendritic barite crystals and well-formed rhombohedral, rectangular, and polyhedral barite crystals. The 150°C data are from Shikazono (1994) the others from other investigations. D dendritic (spindle-like, rodlike, star-like, cross-like) barite Dp feather-like dendritic barite W well-formed rectangular, rhombohedral, and polyhedral barite. The boundary between the diffusion-controlled mechanism (Di) and the surface reaction mechanism (S) for barite precipitation at 25°C estimated by Nielsen (1958) The solubility product for barite in 1 molal NaCl solution at 150°C based on data by Helgeson (1969) and Blount (1977). A-B The solubility product for barite in 1 molal NaCl solution from 25 to 150°C based on data by Helgeson (1969).

The limited solubility (5, moles per liter) of barium sulfate is reflected in the solubility product for the dissolution. The solubility can be calculated to show that a small amount of barium ion is found free in solution ... 

The solubility 5 of magnesium hydroxide (in units of moles per liter) can be computed from the equilibrium constant (the solubility product) for the dissolution of the salt. For 5 equal to the moles per liter of Mg(OH)2 dissolved ... 

Note The above potentials, E, are for pH 7 at equal concentrations of oxidised and reduced species. These equilibrium values are as important as stability constants and solubility products for an understanding of cellular chemical systems. These are free energy changes in volts, E, and where n3E is in kilocalories. The [Fe3+]/[Fe2+] is related to an equilibrium constant, K (see Section 4.17). 

When a reagent is added to an analyte solution forming a sparingly soluble compound, the solubility product for that compound is immediately exceeded and the solution is said to be supersaturated. The relative supersaturation Rs is given by... 

There have been many determinations of solubility products for lanthanide fluorides over the years. We shall try to show the range of values presented for a given element, as well as the chemically important variation of solubility with the nature of the metal. Values for aqueous solution will be reviewed first, then the effects of added acid or salts on solubility considered. 

Solubility Products for Lanthanum Trifluoride and Cerium Trifluoride in Aqueous Solution at 25°C ... 

Variation op the Solubility Product for Lanthanum Fluoride with Sodium Perchlorate Concentration0... 

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... 

The logarithm of the solubility product for hydroxyapatite is -58.6 and that of fluorapatite (CajtPO jF) is -60.6 (57), and thus, D = 0.01 in favour of fluoride incorporation into the solid apatite precipitate. Accordingly, it should be difficult to prepare solid solutions of these compounds by precipitation from aqueous solution and if prepared batchwise, they are expected to contain logarithmic gradients in their internal composition. Yet, Moreno et al.(M3) report linear changes in the lattice parameters of such solid solutions. They also determined their solubility behavior. 

In that study 5 ), the average of the logarithms of the solubility products for pure hydroxyapatite (log Kg / ) and pure fluorapatite (log Kp/ ) appeared to be - 59.16 and - 60.52 respectively, both with an uncertainty of about + 0.30. In the present study the solubility data found for equilibration of solid solutions are expressed as the negative logarithms for the ionic products of hydroxyapatite and fluorapatite, i.e. 

The System Calciumhydroxyapatite - Leadhydroxyapatite. In this system there is at least one and presumably two miscibility gaps around 1200°C (66). At room temperature there is one large miscibility gap. The solubility product for leadhydroxyapatite (67) is about 10 so that for this system D is about 30000 in favour of lead incorporation into the apatite. This means that upon precipitation, practically all the lead will precipitate before any calcium coprecipitates. 

Chromate ion concentration required to initiate the precipitation of Ag2Cr04 commences at the equivalence point and may be calculated with the solubility products for AgCl and Ag2Cr04 ... 

Khodakovskiy (16) used this assumption to extrapolate dissociation constants for acids, Henry s law constants for gases and solubility products for salts. In a variation of this technique Khodakovskiy (17) has extrapolated partial molal heat capacities of ions and neutral molecules by using C = bT. 

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