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Ionic relation between

Besides light and nutrition, plant water status is an additional important environmental factor influencing the rate of CO2 uptake. In general, the initial phase of this response is a response of stomata, which are more sensitive to water stress than the photosynthetic metabolism. If plant water status decreases further, also photosynthesis is reduced. In laboratory experiments it has been shown, that it is not the leaf water status but hormonal and ionic relations between root and shoot which regulate stomatal opening and photosynthesis under soil water stress (Gollan et al., 1988). [Pg.3594]

Meot-Ner M 1984 Ionic hydrogen bond and ion solvation 2. Solvation of onium ions by 1-7 water molecules. Relations between monomolecular, specific and bulk hydration J. Am. Chem. Soc. 106 1265-72... [Pg.1359]

A great number of monoaza or polyaza. either symmetrica] or unsym-metrical, mono trimethine thiazolocyainines have been synthesized in order to verify or to obtain semiempirical rules, more or less based on the resonance theory, concerning the relation between the color of a thiazolo dye and the number and place of nitrogen atoms in the chromophoric chain. For example. Forster s rule applies to ionic dyes and stipulates that the will increase with the decreasing tendency of chromophoric atoms lying between the two auxochromes to take up the characteristic charges (90). [Pg.78]

Complete and Incomplete Ionic Dissociation. In the foregoing chapter mention has been made of electrolytes that are completely dissociated in solution, and of weak electrolytes where free ions are accompanied by a certain proportion of neutral molecules. In the nineteenth century it was thought that aqueous solutions of even the strongest electrolytes contained a small proportion of neutral molecules. Opinion as to the relation between strong and weak electrolytes has passed through certain vicissitudes and we shall describe later how this problem has been resolved. [Pg.38]

When an ionic solution contains neutral molecules, their presence may be inferred from the osmotic and thermodynamic properties of the solution. In addition there are two important effects that disclose the presence of neutral molecules (1) in many cases the absorption spectrum for visible or ultraviolet light is different for a neutral molecule in solution and for the ions into which it dissociates (2) historically, it has been mainly the electrical conductivity of solutions that has been studied to elucidate the relation between weak and strong electrolytes. For each ionic solution the conductivity problem may be stated as follows in this solution is it true that at any moment every ion responds to the applied field as a free ion, or must we say that a certain fraction of the solute fails to respond to the field as free ions, either because it consists of neutral undissociated molecules, or for some other reason ... [Pg.38]

In this discussion we shall need to go right back to Chapter 1 and shall need to put together various aspects of ionic processes that have been considered separately in the preceding six chapters. In Sec. 15 we noticed that the relation between equations (26) and (25) was precisely the same as the relation between the equations (19) and (18) that had been obtained in Chapter 1. In Sec. 17 we discussed one type of proton transfer, which involved the formation of two ions at a great distance apart and in the footnote to Sec. 17 it was pointed out that the discussion of equation (27) given in Sec. 15 will apply to the electrostatic part of J. Proton transfers were also considered in Sec. 31 but hitherto we have examined only the type... [Pg.113]

When an ionic solid consists of anions and cations of different charges, the relation between Ksp and s takes a different form, but the principle is the same (Example 16.4). [Pg.435]

Relations between softness, covalent bonding, ionicity and electric polarizability. C. K. Jorgensen. Struct. Bonding (Berlin), 1967, 3, 106-115 (39). [Pg.36]

The effect of pH and complexation on the relative stabilities of the oxidation states of Pu is discussed. A set of ionic radii are presented for Pu in different oxidation states and different coordination numbers. A model for Pu hydration is presented and the relation between hydrolysis and oxidation state evaluated, including the problem of hydrous polymerization. [Pg.214]

An interesting point that emerges from Fig. 5.6 is the relation between Ag and (AAgsol)w. p. As seen from the figure, the lowering of the activation energy for the reaction is almost linearly proportional to the stabilization of the ionic resonance form (AAg )w. p. An enzyme which is designed to accelerate a proton transfer between A and B will simply stabilize the (B 1—H A-) state more than water. [Pg.145]

There is, of course, a close relation between atomic arrangement and bond type. Thus the four single bonds of a carbon atom are directed toward the comers of a tetrahedron But tetrahedral and octahedral configurations are also assumed in ionic compounds, so that it is by no means always possible to deduce the bond type from a knowledge of the atomic arrangement. [Pg.300]

Cations can be seen as acting as ionic crosslinks between polyanion chains. Although this may appear a naive concept, crosslinking can be seen as equivalent to attractions between polyions resulting from the fluctuation of the counterion distribution (Section 4.2.13). Moreover, it relates to the classical theory of gelation associated with Flory (1953). Divalent cations (Zn and Ca +) have the potential to link two polyanion chains. Of course, unlike covalent crosslinks, ionic links are easily broken and re-formed under stress there could therefore be chain slipping and this may explain the plastic nature of zinc polycarboxylate cement. [Pg.101]

The point defects are decisive for conduction in solid ionic crystals. Ionic migration occurs in the form of relay-type jumps of the ions into the nearest vacancies (along the held). The relation between conductivity o and the vacancy concentration is unambiguous, so that this concentration can also be determined from conductivity data. [Pg.136]

Previously, we have proposed that SFG intensity due to interfacial water at quartz/ water interfaces reflects the number of oriented water molecules within the electric double layer and, in turn, the double layer thickness based on the p H dependence of the SFG intensity [10] and a linear relation between the SFG intensity and (ionic strength) [12]. In the case of the Pt/electrolyte solution interface the drop in the potential profile in the vicinity ofelectrode become precipitous as the electrode becomes more highly charged. Thus, the ordered water layer in the vicinity of the electrode surface becomes thiimer as the electrode is more highly charged. Since the number of ordered water molecules becomes smaller, the SFG intensity should become weaker at potentials away from the pzc. This is contrary to the experimental result. [Pg.81]

Shimizu, T. and Kenndler, E., Capillary electrophoresis of small solutes in linear polymer solutions Relation between ionic mobility, diffusion coefficient and viscosity, Electrophoresis, 20, 3364, 1999. [Pg.437]

Relations between Softness, Covalent Bonding, Ionicity and Electric Polarizability. Vol. 3, pp. 106—115. [Pg.174]

The fact is, ionic interaction between dyes, fibres and electrolytes is only part of the story. As Yang [1] has pointed out, hydrophobic interactions also need to be taken into consideration. Whilst this has been accepted for many years in relation to dye-fibre interactions, the extension of the concept to interactions involving neutral electrolytes is novel. [Pg.35]

Figure 2.3. Elemental enrichment factors in baterial and fungi, plotted on a log scale against the ionic potential of the elements (after Banin and Navrot, 1975. Reprinted from Science, 189, Banin A. and Navrot J., Origin of Life Clues from relations between chemical compositions of living organisms and natural environments, pp 550-551, Copyright (1975), with permission from AAAS)... Figure 2.3. Elemental enrichment factors in baterial and fungi, plotted on a log scale against the ionic potential of the elements (after Banin and Navrot, 1975. Reprinted from Science, 189, Banin A. and Navrot J., Origin of Life Clues from relations between chemical compositions of living organisms and natural environments, pp 550-551, Copyright (1975), with permission from AAAS)...
The relation between electrophoretic mobility y and the surface properties of the particle (usually modeled as an ionic double layer for aqueous systems) is a classical problem in colloid science. [Pg.257]

The EC (pS cm-1) and the TDS (mg L ) both reflect the water ionic content, i.e. the dissolved load also called water salinity. The EC, easily obtained compared to chemical data, is thus widely documented in the CHEBRO database (n = 2,860 versus 999 complete major element analyses). These two parameters (EC and TDS) are linked by a linear relation TDS (mg L ) = b EC (pS cm-1), with a mean b factor 0.54 < b < 0.96 according to water types and range of salinity [21, 22], The linear relations between TDS and EC were calculated for each monitoring station, b factor ranging from 0.713 (Arga) and 0.86 (Aragon), whereas the Ebro River stations present less variability (0.774—0.798) with R2 always better than 0.72, all the relations are summarised in Table 1. These relations are very similar to that defined for the whole Ebro basin with b = 0.81 [23]. [Pg.105]

Conductivity sensors are most commonly used for safety purposes in household appliances. Presence and absence of washing liquor, detergency, and water softener can be easily measured and proper operation ensured [71]. The various applications mainly differ by their design of electrode geometry and methods for electrical measurement. Due to the close relation between ionic conductivity and water hardness, the automatic water softener in an automatic dishwasher can be controlled by a conductivity sensor [72]. To isolate the transmission of the measured value from the process controller, the conductivity sensor could incorporate an opto-electronical coupling [73]. Thus, protective insulation of the electrodes in a washer-dryer could be ensured. [Pg.107]

In the discussions of micellar effects thus far there has been essentially no discussion of the possible effect of micellar charge upon reactivity in the micellar pseudophase. This is an interesting point because in most of the original discussions of micellar rate effects it was assumed that rate constants in micelles were affected by the presence of polar or ionic head groups. It is impracticable to seek an answer to this question for spontaneous reactions of anionic substrates because they bind weakly if at all to anionic micelles (p. 245). The problem can be examined for spontaneous unimolecular and water-catalysed reactions of non-ionic substrates in cationic and anionic micelles, and there appears to be a significant relation between reaction mechanism and the effect of micellar charge upon the rate of the spontaneous hydrolysis of micellar-bound substrates. [Pg.247]

See Pauling, note 14, pp. 97ff. Coulson, note 21, p. 141, states Now there must be some relation between the percentage ionic character and the electronegativity difference xB — xA. It is of the very essence of the idea of an electronegativity scale that this should be so. ... [Pg.355]

It has been noted that the conductivity and activation energy can be correlated with the ionic radius of the dopant ions, with a minimum in activation energy occurring for those dopants whose radius most closely matches that of Ce4+. Kilner et al. [83] suggested that it would be more appropriate to evaluate the relative ion mismatch of dopant and host by comparing the cubic lattice parameter of the relevant rare-earth oxide. Kim [84] extended this approach by a systematic analysis of the effect of dopant ionic radius upon the relevant host lattice and gave the following empirical relation between the lattice constant of doped-ceria solid solutions and the ionic radius of the dopants. [Pg.21]

The ionic conductivity at the end of a polymerisation is due to whatever cations Pn+ are formed or left when the monomer is exhausted and the anions A- of the initiating salt, plus a very minor contribution from the ions formed from impurities, which will be ignored. In order to analyse the relation between the observed iq, c0 and the ionic conductivity A of the electrolyte, it is necessary to clarify the electrochemistry of the solutions. We note first that the polymeric cations, whatever their structure, (i.e., as they were when propagating or subsequently isomerised), are much larger than the anions, SbF6, so that these carry virtually all the current so that A A, (SbF6), and therefore A, can be calculated-see below. Next, we note that all the iq- c0 plots, including that reported earlier [2], are rectilinear. This means ... [Pg.483]


See other pages where Ionic relation between is mentioned: [Pg.189]    [Pg.526]    [Pg.3]    [Pg.25]    [Pg.234]    [Pg.180]    [Pg.8]    [Pg.21]    [Pg.324]    [Pg.2]    [Pg.194]    [Pg.187]    [Pg.271]    [Pg.144]    [Pg.22]    [Pg.193]   
See also in sourсe #XX -- [ Pg.156 ]




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RELATION BETWEEN COVALENT AND IONIC BONDS

Relation between

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