Solubility small crystals

Colorless, transparent, small crystals. Solubility in water (18°C) 1.6 g./liter. Soluble in HF and NH Cl solutions. 

Bikerman [179] has argued that the Kelvin equation should not apply to crystals, that is, in terms of increased vapor pressure or solubility of small crystals. The reasoning is that perfect crystals of whatever size will consist of plane facets whose radius of curvature is therefore infinite. On a molecular scale, it is argued that local condensation-evaporation equilibrium on a crystal plane should not be affected by the extent of the plane, that is, the crystal size, since molecular forces are short range. This conclusion is contrary to that in Section VII-2C. Discuss the situation. The derivation of the Kelvin equation in Ref. 180 is helpful. 

In principle, then, small crystals should show a higher solubility in a given solvent than should large ones. A corollary is that a mass of small crystals should eventually recrystallize to a single crystal (see Ostwald ripening. Section IX-4). 

Add 1 drop (0 05 ml.) of concentrated nitric acid to 2 0 ml. of a 0 5 per cent, aqueous solution of paraperiodic acid (HjIO,) contained in a small test-tube and shake well. Then introduce 1 op or a small crystal of the compound. Shake the mixture for 15 seconds and add 1-2 drops of 5 per cent, aqueous silver nitrate. The immediate production of a white precipitate (silver iodate) constitutes a positive test and indicates that the organic compound has been oxidised by the periodic acid. The test is based upon the fact that silver iodate is sparingly soluble in dilute nitric acid whereas silver periodate is very soluble if too much nitric acid is present, the silver iodate will not precipitate. 

Acetylenedicarboxylic acid monopotassium salt [928-04-1] M 152.2. Very soluble in H2O, but can be crystd from small volume of H2O in small crystals. These are washed with EtOH and dried over H2SO4 at 125°. [Chem Ber 10 841 1877, Justus Liebigs Ann Chem 272 133 1893.]... 

Solubility is also affected by particle size, small crystals (<1 pm say) exhibiting a greater solubility than large ones. This relationship is quantified in the Gibbs-Thomson, Ostwald-Freundlich equation (see Mullin, 2001)... 

The product consists of very small crystals having a powdery aspect and a pink color which deepens on contact with air. This product is very soluble in water and alcohol, and insoluble in ether. 

Efflorescence usually takes place when groundwater penetrates within porous solids, where it leaches (dissolves) soluble salts from the solids. When the water with the leached solids eventually evaporates, the solution migrates toward the surface if the water continues to evaporate, the dissolved salts are redeposited, forming small crystals just below and on the surface of the objects. The forces generated by the crystallization of the efflorescent salts below the surface (in the bulk of the solid), as well as... 

The recent crystallization of the small water-soluble transcriptional regulator of Bacillus subtilis multidrug transporter Bmr, BmrR, which binds hydrophobic cations from the cytosol [64, 65] provides a good example for an interaction determined primarily by van der Waals interactions. Interestingly, the same drugs, which bind to the water-soluble BmrR are also substrates for the transmembrane multidrug transporter Bmr. As will be discussed below, the latter interactions could well be of different nature. 

For this method, either a weighed amount of the solute (or a definite amount of the solvent) is placed in a suitable vessel. While agitating the system at constant temperature, known amounts of the solvent (or the solute) are added gradually until the solubility limit is reached. Appropriate checks must be carried out to ensure that the system is very close to equilibrium when the content or temperature of the system is recorded. In this method of temperature variation, attention is usually focused on the last small crystal. The equilibrium temperature is taken as the mean of the two temperatures at which the crystal either slowly grows or slowly dissolves. This procedure may also be carried out at the microscale by examining a small volume of the system under a hot-stage microscope. 

Ostwald ripening chem Solution-crystallizer phenomenon in which small crystals, more soluble than large ones, dissolve and reprecipitate onto larger particles. ost, valt rTp-a-nii) ... 

Colorless, transparent, large rhomhohedral crystals, or white small crystals hitter, caustic metallic taste odorless pure compound is not sensitive to light hut trace organics promote photo reduction, turning the salt to grayish hlack on exposure to light density 4.35 g/cm melts at 212°C decomposes at 440°C very soluble in water, soluble in ethanol and acetone. 

The monohydrate consists of colorless and odorless small crystals or cys-talline powder orthorhombic structure refractive index 1.420 hardness 1.3 Mohs density 2.25 g/cm loses water at 100°C becoming anhydrous very soluble in water insoluble in ethanol. 

For low selenosulphate concentrations, only the small crystals were formed, even in thicker films, and this was rationalized by the lower steady-state selenide concentration, which would favor cluster growth over ion-by-ion formation (the product of free lead and selenide ions needs to be larger than the solubility product of PbSe for ion-by-ion deposition to occur). An important difference between the citrate depositions and the NTA or hydroxide ones is that, even in the ion-by-ion citrate deposition, some low concentration of colloidal hydrated oxide was present, due to the relatively low complexing strength of citrate. The pH of the hydroxide baths (> 13) was much higher than that of the citrate or NT A baths (10.8). 

Lower a small crystal of Glauber salt into the solution. Explain what happens. Draw curves of the solubility of anhydrous sodium sulphate and its crystallohydrates. Acquaint yourself with the phase diagram of the sodium sulphate-water system. In what parts of the diagram is the system invariant, monovariant, or divariant ... 

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