Aqueous solutions Physical properties

Ethylene oxide aqueous solutions, physical properties of, 20 635t Ethylene oxide catalysts, 20 648-649 Ethylene oxide hydrolysis, rate constants for, 20 638t... 

Physical Properties. Pure, anhydrous lactic acid is a white, crystalline soHd with a low melting poiat. However, it is difficult to prepare the pure anhydrous form of lactic acid generally, it is available as a dilute or concentrated aqueous solution. The properties of lactic acid and its derivatives have been reviewed (6). A few important physical and thermodynamic properties from this reference are summarized ia Table 1. 

Horvath, A. L., Handbook of Aqueous Electrolyte Solutions, Physical Properties, Estimation and Correlation Methods, Ellis Horwood, Chichester, 1985. 

The early chapters in this book deal with chemical reactions. Stoichiometry is covered in Chapters 3 and 4, with special emphasis on reactions in aqueous solutions. The properties of gases are treated in Chapter 5, followed by coverage of gas phase equilibria in Chapter 6. Acid-base equilibria are covered in Chapter 7, and Chapter 8 deals with additional aqueous equilibria. Thermodynamics is covered in two chapters Chapter 9 deals with thermochemistry and the first law of thermodynamics Chapter 10 treats the topics associated with the second law of thermodynamics. The discussion of electrochemistry follows in Chapter 11. Atomic theory and quantum mechanics are covered in Chapter 12, followed by two chapters on chemical bonding and modern spectroscopy (Chapters 13 and 14). Chemical kinetics is discussed in Chapter 15, followed by coverage of solids and liquids in Chapter 16, and the physical properties of solutions in Chapter 17. A systematic treatment of the descriptive chemistry of the representative elements is given in Chapters 18 and 19, and of the transition metals in Chapter 20. Chapter 21 covers topics in nuclear chemistry and Chapter 22 provides an introduction to organic chemistry and to the most important biomolecules. 

Note that molality includes the quantity of solvent, not solution. And, most important, molal solutions are prepared by measuring masses of solute and solvent, not solvent or solution volume. Mass does not change with temperature, so neither does molality. Moreover, unlike volumes, masses are additive adding 500. g of one solution to 500. g of another does give 1000. g of final solution. For these reasons, molality is a preferred unit when temperature, and hence density, may change, as in the examination of solutions physical properties. For the special case of water, 1 L has a mass of 1 kg, so molality and molarity are nearly the same for dilute aqueous solutions. 

Horvath, A.L. (1985) Handbook of Aqueous Electrolyte Solutions Physical Properties, Estimation Methods and Correlation Methods. EUis Horwood, West Sussex, England. 

Horvath, ALHandbook of Aqueous Electrolyte Solutions. Physical Properties.Esti-mation and Correlation Methodsfo mVh e.y and Sons New York, 985. 

Physical properties. All colourless. Formaldehyde, HCHO, is a gas, and only its aqueous solution, which has a characteristic pungent odour, is considered metaformaldehyde or trioxymethylene , (CH20)3, is a solid polymer, insoluble in water and ethanol. 

Physical properties. Majority are liquids except p toluidine and 1- and 2-naphthylamine. All are colourless when pure, but rapidly darken on exposure to air and light. All are very sparingly soluble in water, but dissolve readily in dilute mineral acids (except the naphthyl-amines, which are only moderately soluble in adds). They form colourless crystalline salts e.g., CjHjNH2,HCl) which are soluble in water these aqueous solutions usually have an add reaction owing to hydrolysis, and give the reactions of both the amine and the acid from which they are derived. Addition of alkali to the acid solution liberates the amine. 

Physical Properties. Glycine is a colourless crystalline solid soluble in water. Owing to the almost equal opposing effects of the amino and the carboxylic groups. its aqueous solution is almost neutral (actually, slightly acidic to phenolphthalein) and glycine is therefore known as a neutral ampholyte. f It exhibits both acidic and basic properties. 

Note the obvious physical properties appearance, colour, state, odour, solubility in (or reaction with) water, whether aqueous solution is neutral or otherwise. 

Butynediol. Butynediol, 2-butyne-l,4-diol, [110-65-6] was first synthesized in 1906 by reaction of acetylene bis(magnesium bromide) with paraformaldehyde (43). It is available commercially as a crystalline soHd or a 35% aqueous solution manufactured by ethynylation of formaldehyde. Physical properties are Hsted in Table 2. 

Table 3. Physical Properties of 50% Aqueous Acrylamide Solution ...

Physical Properties. Mahc acid crystallines from aqueous solutions as white, translucent, anhydrous crystal. The S(—) isomer melts at 100-103°C (1) and the R(+) isomer at 98-99°C (2). On heating, D,L-mahc acid decomposes at ca 180°C by forming fumaric acid and maleic anhydride. Under normal conditions, malic acid is stable under conditions of high humidity, it is hygroscopic. 

Mahc acid is a relatively strong acid. Its dissociation constants are given in Table 1. The pH of a 0.001% aqueous solution is 3.80, that of 0.1% solution is 2.80, and that of a 1.0% solution is 2.34. Many of its physical properties are similar to those of citric acid (qv). Solubihty characteristics are shown in Figure 1 and Table 1, densities of aqueous solutions are hsted in Table 2, and pH values vs concentration are shown in Figure 2. 

Physical Properties. When crystaUized from aqueous solutions above 5°C, natural (R-R, R )-tartaric acid is obtained in the anhydrous form. Below 5°C, tartaric acid forms a monohydrate which is unstable at room temperature. The optical rotation of an aqueous solution varies with concentration. It is stable in air and racemizes with great ease on heating. Some of the physical properties of (R-R, R )-tartaric acid are Hsted in Table 7. 

Ethyleneimine (El) and its two most important derivatives, 2-methyla2iridine [75-55-8] (propyleneimine) (PI) and l-(2-hydroxyethyl)a2iridine [1072-52-2] (HEA) are colodess Hquids. They are miscible ia all proportions with water and the majority of organic solvents. Ethyleneimine is not miscible with concentrated aqueous NaOH solutions (>17% by weight) (24). Ethyleneimine has an odor similar to ammonia and is detectable only at concentrations >2 ppm. The physical properties of ethyleneimine and the derivatives mentioned are given ia Table 1. Thermodynamic data can be found ia the Hterature (32). 

Extensive hydrogen bonding takes place in phosphoric acid solutions. In concentrated (86% H PO solutions, as well as in the crystal stmctures of the anhydrous acid and the hemihydrate, the tetrahedral H PO groups are linked by hydrogen bonding. At lower (75% H PO concentrations, the tetrahedra are hydrogen-bonded to the water lattice. Physical properties of phosphoric acid solutions of various concentrations are Hsted in Table 2 the vapor pressure of aqueous H PO solutions at various temperatures is given in Table 3. 

Table 2. Physical Properties of Aqueous Solutions of Phosphoric Acid...

Physical and chemical properties of the numerous PAG products can vary considerably. PAG products are usually aqueous solutions, although soHd products are also sold. Solutions range from colodess to amber and from clear to hazy in appearance specific gravities at 25 °G vary from about 1.2 to 1.35. Product viscosities, as measured by a Brookfield viscometer at 25 °G, are generally about 10 50 mPa-s(=cP), but can be much greater than 10, 000 mPa-s(=cP) for certain aged compositions. 

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