Potassium chloride molecule

The gaseous potassium chloride molecule has a measured dipole moment of 10.3 D, which indicates that it is a very polar molecule. The separation between the nuclei in this molecule is 2.67 A. What would the dipole moment of a KCl molecule be if there were opposite charges of one fundamental unit (1.60 X 10 C) at the nuclei ... 

Potassium chloride molecule, 307f theory, 307ff... 

Mobility of Ions in D20. The viscosity of liquid D20 at room temperature has a value 1,232 times the viscosity of H20. Since the D2O and HaO molecules are so similar in other respects, we should expect the mobility of ions dissolved in D20 to be smaller than in H20. The conductivity of potassium chloride and potassium acetate was measured in mixtures of D20 and H20 up to a composition containing 97 per cent of D20.1 The values for ions in D2O, given in Table 7, were obtained by extrapolation from values obtained in the mixed solvent containing a few per cent of H20. As was expected, the conductivity in D20 was found to be smaller than in H20. But the change was not quite so great as the change in the viscosity, as is shown by the ratios in the last column of Table 7. We must conclude that, for some or all of the ions, the... 

As discussed in Section 3-, whenever an ionic solid dissolves in water, the salt breaks apart to give a solution of cations and anions. Thus, in any aqueous salt solution the major species are water molecules and the cations and anions generated by the salt. For example, a solution of potassium chloride contains K and Cl ions and H2 O molecules as major species. Likewise, the major species in a solution of ammonium nitrate are NH4 , NO3, and H2 O. 

Langmuir obtained a value of t = 4 A. for the thickness of a water molecule in the surface of a solution of potassium chloride. From a knowledge of the molecular volume we obtain a cross-... 

G. Tammann found that potassium and sodium chlorides form a continuous series of mixed crystals between 660° and 500°. Since neither salt has a transition point, the phenomena observed when the mixed crystals are cooled must be attributed to separation of the components. With diminishing temperature, therefore, either the attractive forces within the molecules of the respective chloride must increase, or those between the unlike molecules must be greatly weakened. The results obtained by etching the individual crystals at the ordinary temperature indicate that the intra-molecular forces of the potassium chloride crystals differ from those of the sodium chloride crystal, or, more precisely, that certain lattice regions are more closely united in the former, whilst such differences are not observed in the latter. In the light of these observations, it is surprising that the X-ray analysis indicates the same lattice for each crystal. 

Gropp measured the conductivity of liquid and frozen soln. of lithium, sodium, and potassium chlorides. F. Ratig studied the electro-chemical action—vide alkali chlorates. The electrical conductivity of soln. of lithium chloride in several non-aqueous solvents has been investigated. Formic acid as a solvent exerts an ionizing power of the same order of magnitude as water in acetic acid, the lithium chloride seems to be partially associated to double molecules, > and in some solvent,... 

Molecular weights.—The composition of the alkali chlorides has been established by analyses. These salts contain alkali, R, and chlorine, Cl, in the proportion 1 1. Consequently, the mol. formulse are represented by RnCln. The difficult volatility of sodium chloride—contrasted with say mercuric chloride—suggests a complex molecule. W. Nernst 78 found the vapour density of both sodium and potassium chlorides, at 2000°, corresponded with the respective formula NaCl and KC1 for the vapours of these salts. L. Riigheimer found that the effect of sodium chloride on the b.p. of bismuth trichloride corresponded with the simple formula NaCl and E. Beckmann obtained a similar result from the effect of sodium, potassium, rubidium, and csesium chlorides on the f.p. of mercuric chloride. 

This double salt is made easily by dissolving potassium chloride, KC1, and cupric chloride, CuCl2-2H20, in water in the proportion of two molecules of the former to one of the latter and evaporating the solution to crystallization. This salt, as well as the corresponding ammonium salt, is used in the determination of carbon in iron. Iron dissolves in a concentrated solution of the salt, leaving the carbon undissolved, and the latter can be filtered off and estimated by combustion. 

ACTIVITY COEFFICIENT. A fractional number which when multiplied by the molar concentration of a substance in solution yields the chemical activity. This term provides an approximation of how much interaction exists between molecules at higher concentrations. Activity coefficients and activities are most commonly obtained from measurements of vapor-pressure lowering, freezing-point depression, boiling-point elevation, solubility, and electromotive force. In certain cases, activity coefficients can be estimated theoretically. As commonly used, activity is a relative quantity having unit value in some chosen standard state. Thus, the standard state of unit activity for water, dty, in aqueous solutions of potassium chloride is pure liquid water at one atmosphere pressure and the given temperature. The standard slate for the activity of a solute like potassium chloride is often so defined as to make the ratio of the activity to the concentration of solute approach unity as Ihe concentration decreases to zero. 

There have been numerous theoretical and experimental investigations on the adsorption of argon, oxygen, and nitrogen on potassium chloride (126-128) and in this connection we may refer to a survey in Brunauer s book on physical adsorption (129). There seems to be a general agreement that the most favorable positions for the adsorbed atoms or molecules will be found just above the center of a lattice cell. The electrostatic polarization is minimum at such spots, but the nonpolar van der Waals forces are at their maximum and dominate (130). Drain... 

Potassium Hexachlor-rhodite, Iv3RhCl6. Aq., was stated by Claus 2 to be formed on dissolving the hydrated sesquioxide in hydrochloric acid and adding a concentrated solution of potassium chloride. The yellow, acid solution becomes gradually red in colour, and in the course of a few weeks dark red, efflorescent crystals separate out. These were found to contain six molecules of water, of which three were readily lost on exposure to air. 

Compounds—even ionic compounds— have no net charge. In the compound potassium chloride, there are potassium ions and chloride ions the oppositely charged ions attract one another and form a regular geometric arrangement, as shown in Fig. 5-1. This attraction is called an ionic bond. There are equal numbers of K+ ions and CC ions, and the compound is electrically neutral. It would be inaccurate to speak of a molecule of solid potassium chloride or of a bond between a specific potassium ion and a specific chloride ion. The substance KCl is extremely stable because of (1) the stable electronic configurations of the ions and (2) the attractions between the oppositely charged ions. 

Nonionic surfactants dissolve in aqueous solutions through hydrogen bonding between the water molecules and the oxyethylenic portion of the surfactant. These interactions are weak but enough in number to maintain the molecule in solution up to the cloud point temperature, at which the surfactant separates as a different phase (4). Figure 3 shows that electrolytes like calcium chloride, potassium chloride, or sodium chloride reduce the cloud point of Triton X-100. Hydrochloric acid instead promoted a salting-in effect similar to that observed for ethanol. 

Many properties of electrolytic solutions are additive functions of the properties of the respective ions this is at once evident from the fact that the chemical properties of a salt solution are those of its constituent ions. For example, potassium chloride in solution has no chemical reactions which are characteristic of the compound itself, but only those of potassium and chloride ions. These properties are possessed equally by almost all potassium salts and all chlorides, respectively. Similarly, the characteristic chemical properties of acids and alkalis, in aqueous solution, are those of hydrogen and hydroxyl ions, respectively. Certain physical properties of electrolytes are also additive in nature the most outstanding example is the electrical conductance at infinite dilution. It will be seen in Chap. II that conductance values can be ascribed to all ions, and the appropriate conductance of any electrolyte is equal to the sum of the values for the individual ions. The densities of electrolytic solutions have also been found to be additive functions of the properties of the constituent ions. The catalytic effects of various acids and bases, and of mixtures with their salts, can be accounted for by associating a definite catalytic coefl5.cient with each type of ion since undissociated molecules often have appreciable catalytic properties due allowance must be made for their contribution. 

This equation means that one atom of magnesium unites with one atom of oxygen, and forms one molecule of magnesium oxide In Exp. i6 it was shown that potassium chlorate when heated yields oxygen and a residue (called potassium chloride). This reaction is represented in the simplest way by the equation —... 

This equation means that one molecule of potassium chlorate yields by decomposition three atoms of oxygen and one molecule of potassium chloride. It has been shown as the result of several experiments that the interaction of zinc and sulphuric acid produces hydrogen and zinc sulphate. This fact is represented by the equation —... 

The molecular weight of potassium chloride, found by adding its atomic weights, is 74.5, it being assumed that the molecule contains one atom each of potassium and chlorine. 

Solution. We know that the solubility of lead chloride is less in a solution containing chloride ion than in pure water, because of the common-ion effect, discussed above. Let us solve this problem by introducing the symbol x, equal to the solubility, in gfw per liter, of lead chloride in 1 F pdtassiqm chloride solution. Each molecule of lead chloride introduces one lead ion and two chloride ions accordingly x gfw of PbCl in a liter of solution would produce x mole/1 of lead ion and 2x mole/1 of chloride ion. However, the solution already contains 1 mole per liter of chloride ion, resulting from the ionization of the 1 gfw/1 of potassium chloride present. Hence we see that the total concentration of lead ion in the saturated solution is x, and the total concentration of chloride ion is 2x 1 ... 

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