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Lead ions

Passage through the quadmpole assembly is described as stable motion, while those trajectories that lead ions to strike the poles is called unstable motion. From mathematical solutions to the equations of motion for the ions, based on Equation 25.1, two factors (a and q Equation 25.2) emerge as being important in defining regions of stable ion trajectory. [Pg.187]

Tetravalent lead is obtained when the metal is subjected to strong oxidizing action, such as in the electrolytic oxidation of lead anodes to lead dioxide, Pb02 when bivalent lead compounds are subjected to powerful oxidizing conditions, as in the calcination of lead monoxide to lead tetroxide, Pb O or by wet oxidation of bivalent lead ions to lead dioxide by chlorine water. The inorganic compounds of tetravalent lead are relatively unstable eg, in the presence of water they hydrolyze to give lead dioxide. [Pg.67]

Lead Telluride. Lead teUuride [1314-91 -6] PbTe, forms white cubic crystals, mol wt 334.79, sp gr 8.16, and has a hardness of 3 on the Mohs scale. It is very slightly soluble in water, melts at 917°C, and is prepared by melting lead and tellurium together. Lead teUuride has semiconductive and photoconductive properties. It is used in pyrometry, in heat-sensing instmments such as bolometers and infrared spectroscopes (see Infrared technology AND RAMAN SPECTROSCOPY), and in thermoelectric elements to convert heat directly to electricity (33,34,83). Lead teUuride is also used in catalysts for oxygen reduction in fuel ceUs (qv) (84), as cathodes in primary batteries with lithium anodes (85), in electrical contacts for vacuum switches (86), in lead-ion selective electrodes (87), in tunable lasers (qv) (88), and in thermistors (89). [Pg.69]

In lead zh conate, PbZrOs, the larger lead ions are displaced alternately from the cube corner sites to produce an antifeiToelectric. This can readily be converted to a feiToelectric by dre substitution of Ti" + ions for some of the Zr + ions, the maximum value of permittivity occumirg at about the 50 50 mixture of PbZrOs and PbTiOs. The resulting PZT ceramics are used in a number of capacitance and electro-optic applicahons. The major problem in dre preparation of these solid soluhons is the volatility of PbO. This is overcome by... [Pg.236]

The alkaline filtrate and washings are combined and partially neutralized by the addition of 150-175 ml. of concentrated hydrochloric acid. Sufficient sodium sulfide solution is added to precipitate all the lead ion present (Note 6). The suspension is brought to a gentle boil to coagulate the lead sulfide, allowed to cool somewhat, and filtered with suction. The filtrate is placed in a 2-1. beaker set in an ice bath and acidified Caution in the hood) with about 150 ml. of concentrated hydrochloric acid to precipitate crude 2-hydroxyisophthalic acid monohydrate (Note 7). The suspension is cooled to 0-5° and filtered to separate the crude acid, which weighs 35-49 g. after being dried in a vacuum oven at 110°/50-150 mm. for 5 hours (Note 8). [Pg.49]

These figures furnish a handy summary of solubility behavior. We see from Figure 10-5A that few chlorides have low solubilities. The few that do contain cations of metals clustered toward the right side of the periodic table (silver ion, Ag+, cuprous ion, Cu+, mercurous ion, HgJ2, and lead ion, Pb+2) but they do not fall in a single column. This irregularity is not un-... [Pg.171]

Lead. 25.0 mL lead ion solution + solid hexamine to pH about 4.6. [Pg.588]

Make the connections to the polarographic analyser and adjust the applied voltage to —0.8 V, i.e. a value well in excess of the deposition potential of lead ions. Set the stirrer in motion noting the setting of the speed controller, and after 15-20 seconds, switch on the electrolysis current and at the same time start a stopclock allow electrolysis to proceed for 5 minutes. On completion of the electrolysis time, turn off the stirrer, but leave the electrolysis potential applied to the cell. After 30 seconds to allow the liquid to become quiescent, replace the electrolysis current by the pulsed stripping potential and set the chart recorder in motion. When the lead peak at ca 0.5 V has been passed, turn... [Pg.625]

Both lead ion and dichromate ion yield a diffusion current at an applied potential to a dropping mercury electrode of —1.0 volt against the saturated calomel electrode (S.C.E.). Amperometric titration gives a V-shaped curve [Fig. 16.14 (C)]. The exercise described refers to the determination of lead in lead nitrate the application to the determination of lead in dilute aqueous solutions (10-3 — 10-4lVf) is self-evident. [Pg.630]

Discussion. For the determination of small amounts of lead (0.005-0.25 mg) advantage is taken of the fact that when a sulphide is added to a solution containing lead ions a brown colour, due to the formation of colloidal lead sulphide, is produced. However, for general use the dithizone method (see Section 6.13) is to be preferred and this will be described. [Pg.692]

Curve B describes the corresponding relation for the oxidation of divalent lead ions Pb2+ -> Pb4+, which implies the formation of lead dioxide since Pb4+ does not exist alone ... [Pg.158]

FIGURE 3-7 Normal-pulse (curve A) and differential-pulse (curve B) polarograms for a mixture of 1 mg L-1 cadmium and lead ions. The electrolyte is 0.1 M HNOj. [Pg.71]

Solution The sample lead ion yielded a limiting current of 13 pA (A). The current increases by 8.5 pA upon spiking the sample with 1 mM lead standard (considering the 1 100 dilution B — A). [Pg.98]

These ions in solution exist in d Tiamic equilibrium with the precipitate. The system is dynamic because lead ions and iodide ions continually move in and out of solution it is at equilibrium because the net amount of dissolved ions remains constant. We treat solubility equilibria quantitatively in Chapter 18. [Pg.226]

The equilibrium concentration of Pb ions is stated to be 1.35 X 10 M, but the equilibrium concentration of iodide ions is not stated [Pb2- ],q = 1.35 X iO M[r]g(j — The equilibrium concentration of I is determined by stoichiometric analysis. Initially, the system contains only pure water and solid lead(II) iodide. Enough Pbl2 dissolves to make [Pb ]gq = 1.35 X 10 M. One formula unit of Pbl2 contains one Pb cation and two I" anions. Thus, twice as many iodide ions as lead ions enter the solution. The concentration of I at equilibrium is double that of Pb cations [r],q-2[Pb ],q-2.70 X lO M Substitute the values of the concentrations at equilibrium into the equilibrium expression and calculate the result ... [Pg.1312]

Inorganic lead ions are not known to be metabolized in the body but they are complexed by macromolecules. Lead that is not retained in the body is excreted principally by the kidney as salts or through biliary clearance into the gastrointestinal tract in the form of organometallic conjugates. [Pg.211]

In this study, 4.4 mg of lead equivalent was applied to the skin under a covered wax/plastic patch on the forearms of human subjects of the applied dose, 1.3 mg of lead was not recovered from skin washings. The amount that actually remained in (or on) the skin and the mass balance of the fate of this lead was not determined it may have been absorbed or eliminated from the skin by exfoliation of epidermal cells. Thus, while this study provides evidence for dermal absorption of lead, it did not quantity the fraction of applied dose that was absorbed. The quantitative significance of the dermal absorption pathway as a contributor to lead body burden remains an uncertainty. The wax/plastic patch provided a means by which the lead compounds could permeate or adhere to the skin. The effect of concentration in aqueous solution may cause skin abrasion through enhanced acidity since the lead ion is acidic. Abraded skin is known to promote subsequent higher lead penetration. [Pg.219]

Inorganic Lead. Inorganic lead ion in the body is not known to be metabolized or biotransformed (Phase I processes) it does form complexes with a variety of protein and non-protein ligands (see Section 2.4.1). Primarily, it is absorbed, distributed, and then excreted, often in complexed form (EPA 1986a). [Pg.227]

This dye fluoresces after binding Pb+2 and Ca+2 lead is considered an interferant to the determination of calcium by this approach. However, by complexing the divalent lead ion with the heavy metal chelator TPEN (N,N,N ,N -tetrakis(2-pyridylmethyl)ethylene-diamine) prior to the addition of the fluo-3, the fluorescent... [Pg.444]

Bodnar M, Kjoniksen AL, Molnar RM et al (2008) Nanoparticles formed by complexation of poly-y-glutamic acid with lead ions. J Hazard Mater 153 1185-1192... [Pg.59]

D 3116 25 0.25-25 mg Pb/L PbR4 is converted to ionic organolead by IC1 and then to inorganic lead ions spectrophotometric determination of dithizone (2) complex. [Pg.432]

Selectivity for lead ion is induced by incorporating N, N, 1V JV -tctrabutyl-S.b-dioxa-octanediamide (10) to the membrane of a graphite solid state sensor96. [Pg.438]


See other pages where Lead ions is mentioned: [Pg.36]    [Pg.160]    [Pg.75]    [Pg.84]    [Pg.176]    [Pg.313]    [Pg.627]    [Pg.628]    [Pg.631]    [Pg.164]    [Pg.601]    [Pg.227]    [Pg.261]    [Pg.392]    [Pg.403]    [Pg.39]    [Pg.203]    [Pg.686]    [Pg.29]    [Pg.406]    [Pg.305]    [Pg.407]    [Pg.101]    [Pg.187]    [Pg.71]    [Pg.441]    [Pg.439]    [Pg.440]    [Pg.555]   
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See also in sourсe #XX -- [ Pg.194 ]

See also in sourсe #XX -- [ Pg.2 , Pg.172 ]

See also in sourсe #XX -- [ Pg.755 , Pg.756 ]




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