Potassium chloride freezing point

If we take Dieterici s numbers for the vapour pressures, and Roloff s for the freezing-points, of solutions of potassium chloride, we can calculate the osmotic pressure (P0) from the two equations ... 

Antifreezing agents for cement consist mainly of salts such as calcium chloride, magnesium chloride, sodium chloride, and soda. Calcium chloride is highly corrosive and very restricted in use. Some salts, especially potassium chloride, will affect the curing time of cement. The latter chemical is in fact used to increase the pot life of cement. Likewise, alcohol freezing-point depressants, such as ethylene glycol, can be also included in the composition [1022]. 

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. 

The isomer is extracted from the residue by treatment with a minimum amount (50 to 60 ml.) of hot benzene. The white residual potassium chloride is removed by filtration. After filtration the benzene solution is evaporated to half volume and cooled in an ice bath (freezing point of benzene is 5.5°), whereupon fine, yellow crystals of the ds isomer form. The crystals are separated by suction filtra-... 

The collected urine is centrifuged to remove solid debris and analyzed by standard methods for sodium, potassium and chloride (Durst and Siggard-Andersen, 1999, Scott et al. 1999). Osmolality is also measured with an osmometer (the freezing point depression type of instrument is recommended (Scott et al. 1999). 

Atomic Weight.—The chemical properties of caesium indicate its close relationship to the other alkali-metals. It is univalent, forming compounds of the type CsX, its atomic weight and hydrogen equivalent being the same. Its atomic weight is of the order Cs =133 a value conformed by the specific-heat method (Vol. I., p. 88) by the isomorphism of the caesium compounds with those of potassium, ammonium, and rubidium (Vol. I., p. 74) by the correspondence of the properties of the metal and its compounds with the periodic system by the formation of a univalent cation and by the depression of the freezing-point of bismuth chloride and mercuric chloride produced by caesium chloride. 

This theory of electrolytic dissociation, or the ionic theory, attracted little attention until 1887 when vanT IIoff s classical paper on the theory of solutions was published. The latter author had shown that the ideal gas law equation, with osmotic pressure in place of gas pressure, was applicable to dilute solutions of non-electrolytes, but that electrolytic solutions showed considerable deviations. For example, the osmotic effect, as measured by depression of the freezing point or in other ways, of hydrochloric acid, alkali chlorides and hydroxides was nearly twice as great as the value to be expected from the gas law equation in some cases, e.g., barium hydroxide, and potassium sulfate and oxalate, the discrepancy was even greater. No explanation of these facts was offered by vanT Iloff, but he introduced an empirical factor i into the gas law equation for electrolytic solutions, thus... 

The equilibrium curve for potassium chloride and water is of the simplest form, consisting only of the two branches AC, the freezing-point curve of water, and CO, the solubility curve of the salt. C is the cryohydric point. This point and the two curves lie in the YT-plane. 

The electroreduction of zirconium halides in alkali halide melts has led to the measurement of reversible potentials (Table XXV) in the temperature range 670°-750°C (550). Phase rule studies of the mixed systems preceded the cell studies and revealed that the phase diagrams of the KCl-ZrCl2 and NaCl-ZrCl2 systems were of the simple eutectic type. The liquidus curves of these binary systems were established by freezing point measurements. The melting point of pure zirconium dichloride was found to be 722° 1°C. In the potassium chloride-zirconium dichloride system, the eutectic is found at 698° 1°C at... 

Formic acid melts at 8.40°C and has a cryoscopic constant Ac = 1.932 K kg mol". These results of J. Lange were obtained by a Beckmann cooling-curve technique in which a differential apparatus gave values of freezing point depression for which a precision of 0.0001 K was reported. Formic acid has a dielectric constant of 58.5 at 16°C and results for potassium chloride, potassium picrate and tetramethylam-monium chloride were fitted to an extended Debye-Hiickel equation for completely dissociated electrolytes. Tetramethylammonium chloride showed the smallest deviation from the limiting law and this was ascribed to the affinity of the organic cation for the solvent. 

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