| 释义 |
molal, a. Physical Chem.|ˈməʊləl|
[f. mole n.7 + -al.]
a. = molar a.3 a, molecular a. 1 a.
1908Goodwin & Mailey in Physical Rev. XXVI. 49 In the fifth column we have computed the values of the fluidity F divided by the corresponding molecular volume ϕ of the liquid; this we have denoted by f and called the molal fluidity. 1923Lewis & Randall Thermodynamics iii. 22 If w is the molal mass of a substance (also known as molal weight or molecular weight), a mol of the substance in question is defined as w grams. 1972Science 2 June 1011/2 Carbon dioxide..has a molecular weight M of 44 and a partial molal volume of 34·8 ml/mole.
b. Of a solution: containing one mole, or a specified number of moles, of solute per kilogramme of solvent or (now rare) per litre of solution. Of a concentration: expressed in terms of these quantities. Cf. molar a.3 b.
1923Lewis & Randall Thermodynamics iv. 33 When we speak of a molal or tenth molal aqueous solution.., we shall refer, not to the concentration, but to the number of mols of solute in 1000 grams of water, which we may call the molality. 1924J. C. W. Frazer in H. S. Taylor Treat. Physical Chem. I. vii. 236 Concentrations expressed in terms of 1000 cc. of solution and using the above methods of expressing the amounts of substances are known as molal, formal or normal concentrations. 1930W. T. Hall Textbk. Quantitative Analysis iii. 26 A solution is said to be molal in hydrogen ions if it contains 1·008 g of H+ per liter. 1938Lundell & Hoffman Outl. Methods Chem. Analysis xxxv. 127 One author will regard a solution containing one mole of solute per liter of solution as molal, whereas another calls such a solution molar. 1965Phillips & Williams Inorg. Chem. I. vii. 250 The activity coefficient is then around 10-14 for molal solutions of these ions. 1970[see molality below].
Hence moˈlality, the molal concentration of a solution.
1923[see sense b above]. 1931[see molarity]. 1963W. J. Moore Physical Chem. (ed. 4) v. 117 One advantage of molality is that it is easy to prepare a solution of given molality by accurate weighing procedures. 1970Man. Symbols & Terminol. Physicochem. Quantities & Units (I.U.P.A.C.) 12 A solution having a molality equal to 0·1 mol kg-1 is sometimes called a 0·1 molal solution. 1973[see molarity]. |