A Temperature-Independent Concentration Unil I n working with weighed amounts of solntion the authors have found it convenient to employ a new system of concentration, the number of gram-formula-weights of solute per kilogram of solution. For want of a n existing name, the term malieity is suggested. This system combines the advantages of malarity and molality. The former offers a convenient method of delivering a known amount of d o t e , hut is temperature dependent. The latter, although temperature i n d e pendent, does not, without further calcnlation, provide the amannt of solute in a.measuredamount of solution. These symbols are defined: X, mole fraction; w, weight fraction; c, molarity; m, molalit,~, 3n, molicity, M, molecular weight; d and do, the densities of t,he solution and pure solvent,, respectively. The suhsrripts 1 and 2 denote solvent and soh~te. These relations ohtain:
c = m d m = 1000 m l ( l 0 0 0
w,
=
- M, m )
M.3n11000.
For very dilute sal~~lions, the first t,hree relations redlice to X2 = 3n M1/lOOO, c = m d o , and rn = 3n.
420
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Journal o f Chemical Educoiion
