Potassium electrical resistivity

Reddish brown metal face-centered cubic crystal density 8.92 g/cm Mohs hardness 2.5 to 3.0 Brinnel hardness 43 (annealed) electrical resistivity 1.71 microhm-cm at 25°C Poisson s ratio 0.33 melts at 1,083°C vaporizes at 2,567°C insoluble in water dissolves in nitric acid and hot sulfuric acid slightly soluble in hydrochloric acid also soluble in ammonium hydroxide, ammonium carbonate and potassium cyanide solutions. 

Silvery metal body-centered cubic structure imparts crimson-red color to flame density 0.862g/cm3 at 20°C melts at 63.25°C density of hquid potassium at 100°C is 0.819 g/cm and 0.771g/cm3 at 300°C vaporizes at 760°C vapor pressure 123 torr at 587°C electrical resistivity 6.1 microhm-cm at 0°C and 15.31 microhm-cm at 100°C viscosity 0.25 centipoise at 250°C surface tension 86 dynes/cm at 100°C thermal neutron absorption cross section 2.07 barns reacts violently with water and acids reacts with alcohol dissolves in liquid ammonia and mercury... 

Grayish-white metal hody-centered cubic crystalline structure density 19.3 g/cm3 melts at 3,422°C vaporizes at 5,555°C vapor pressure 1 torr at 3,990°C electrical resistivity 5.5 microhm-cm at 20°C modulus of elasticity about 50 to 57 x lO psi (single crystal) Poisson s ratio 0.17 magnetic sus-ceptibilty +59 x 10-6 thermal neutron absorption cross section 19.2 + 1.0 barns (2,200m/sec) velocity of sound, about 13,000 ft/sec insoluble in water practically insoluble in most acids and alkabes dissolves slowly in hot concentrated nitric acid dissolves in saturated aqueous solution of sodium chlorate and basic solution of potassium ferricyanide also solubibzed by fusion with sodium hydroxide or sodium carbonate in the presence of potassium nitrate followed by treatment with water... 

Potassium and sodium are good conductors of heat.23 If the conductivity of silver be unity, that of sodium is 0 365. J. W. Hornbeck found the temp, coeff. of the thermal conductivity of potassium or sodium falls with rise of temp. The alkali metals are also good conductors of electricity 24 for example, the conductivity of sodium for heat and electricity is exceeded only by silver, copper, and gold. According to E. F. Northrup, the metals sodium, potassium, mercury, tin, lead, and bismuth have the same value for the ratio of the coeff. of electrical resistance to the coeff. of cubical expansion at the same temp. The electrical conductivity of lithium is nearly ll-4xl04 reciprocal ohms at 20°, that is, about 20 4 per cent, of the conductivity of hard silver of sodium at 2T 70, 22 4 XlO4 reciprocal ohms, that is, about 36 5 per cent, of the value of silver. 

In addition, the separator must have a low electrical resistance, good thermal and chemical stability and must be light in order to retain the high energy density characteristics of the cell. Practical separators have a composite multilayer configuration. A silver-stopping layer of cellophane or non-woven synthetic polyamide is located next to the positive electrode which reduces soluble silver species back to the metal. A potassium titanate paper layer may be placed next to the zinc electrode, and a number of cellophane layers which swell in aqueous KOH make up the middle section. In most cells the separators are fabricated as envelopes or sacks which completely enclose the zinc electrodes. 

C. A. Kraus and W. W. Lucasse measured the electrical resistance of soln. of potassium and sodium in liquid ammonia. 

The results have been reported of a comparative study of the measured electrical resistivities of liquid alkali metals and alloys, and the theoretical predictions for this quantity obtained within the diffraction model.48 The composition dependence of the Knight shifts in Na-Cs, Na-Rb, K-Rb-Cs, and Na-Rb-Cs liquid alloys has also been examined.49 Addition of small quantities of rubidium (0.3—4.51 atom %) to liquid sodium increases the electrical resistivity almost linearly with increasing solute concentration. With increasing temperature from 100 to 1100 °C, the effect of rubidium on the resistivity of sodium progressively diminishes.50 Addition of the solutes Hg, Tl, and Pb increases the resistivity of liquid potassium linearly with both increasing concentration and temperature. The unit increases in resistivity/pfl cm (atom%) , are 8.80, 9.85, and 15.8 for Hg, Tl, and Pb,... 

The membrane which had a thin layer of sulfonyl chloride groups was treated by triethylamine at room temperature for 16 hours, washed with water and then heated at 170°C. Thereafter, the membrane was also immersed in the same mixed solution composed of water, dimethyl sulfoxide and potassium hydroxide as mentioned before. Electric resistance of the membrane was 1.5ft- cm2 when measured in the environment of 3.5 N sodium chloride solution to... 

An apparatus has been developed392 for the analysis of a mixture containing tri-chlorosilane, methyldichlorosilane, silicon tetrachloride, trimethylchlorosilane, di-methyldichlorosilane and methyltrichlorosilane by gas-liquid chromatography on a column of nitrobenzene supported on Celite 545. The column is eluted with nitrogen and the emergent gas is absorbed in flowing 0.01 N potassium ohloride. Hydrolysis of the silanes yields hydrochloric acid which alters the electrical resistance of the potassium chloride solution and this permits quantitative analysis of the silane mixture. 

The studies of elementary films formed in inverse emulsions and stabilized by different synthetic and natural surfactants revealed that the membrane electric conductivity experiences a sharp increase upon the addition of some biologically active surfactants. For instance, membrane conductivity may increase by five orders of magnitude when trace amounts of valinomycin antibiotic are introduced into the outer aqueous medium of lipid membrane. At the same time the membrane becomes permeable to potassium and hydrogen ions but impermeable to sodium ions. A sharp decrease in electric resistance of synthetic membranes is observed when proteins and enzymes with suitable substrates are introduced into them. By studying the properties of such membranes one may model important biological processes, e.g. the transfer of neural impulses. 

The electrical resistance of an ion exchange membrane is an important property that is expressed as electrical resistance per unit area (Q cm2). Though electrical resistance is usually measured in sodium chloride or potassium chloride solution, that of membranes changes remarkably with the species of counter-ions.1 Table... 

Other Thallium Compounds.— The electrical resistivities of K-Tl alloys over a wide range of compositions have been measured. The results suggest that a high degree of localized electron bonding occurs in the liquid alloy at a potassium mole fraction of 0.5. It is possible that the t)q)e of bonding is similar to that occurring in the solid intermetallic compound KTl, which crystallizes at lower temperatures. ... 

The surface area of the electrodes and their arrangement in the conductometric cell influence the electric resistance via the quotient l/A, the so-called cell constant. However, these geometric quantities are often difficult to investigate, especially in the case of platinated electrodes. Therefore, the cell constant is determined by using a calibrating solution of known a value (usually a solution of potassium chloride). These days, commercial equipment for measuring conductivity (conductometer) is... 

The PVC matrix provides the mechanical stability. It is chemically inert and does not dissolve in water. The ionophores are lipophilic organic molecules that selectively interact with the analyte ions. The plasticizer and the lipophilic salt also play an important role in the ion-selective function. They decrease the electric resistance, increase selectivity, and influence the detection limit. As a plasticizer, bis-(2-ethylhexyl)-sebacate (DOS) or 2-nitrophenyl-octyl-ether (oNPOE) is used, while for lipophilic salt potassium-[tetrakis-4-chlorophenyl]-borate is employed most often. 

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