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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: kodos on November 30, 2010, 10:15:01 AM

Title: partial molar volumes - molality
Post by: kodos on November 30, 2010, 10:15:01 AM

The volume of a solution of NaCl at 25ºC is given as:

V/cm³mol^-1 = 1002.9 + 16.40 m + 2.5 m² - 1.2 m³

A: water  B: NaCl

If V_A^*= 18.069 cm³ find the expressions for the partial molar volumes of NaCl and water in this solutions.

ATTEMPT:

m should mean m/m⁰ (molality) and V should mean V_m

(https://www.chemicalforums.com/proxy.php?request=http%3A%2F%2Fwww.forkosh.dreamhost.com%2Fmimetex.cgi%3F%7B+V_B%3D%28%5Cfrac%7B%5Cpartial+V%7D%7B%5Cpartial+n_B%7D%29_%7BT%2Cp%2Cn_A%7D%3D%5Cfrac%7B%5Cpartial+V_mn%7D%7B%5Cpartial+n_B%7D%3Dn%5Cfrac%7B%5Cpartial+V_m%7D%7B%5Cpartial+n_B%7D%2BV_m%5Cfrac%7B%5Cpartial+n%7D%7B%5Cpartial+n_B%7D%3Dn%5Cfrac%7B%5Cpartial+V_m%7D%7B%5Cpartial+m%7D%5Cfrac%7B%5Cpartial+m%7D%7B%5Cpartial+n_B%7D%2BV_m+%7D%3D%5Cfrac%7Bn%7D%7Bn_AM_A%7D%5Cfrac%7B%5Cpartial+V_m%7D%7B%5Cpartial+m%7D%2BV_m&hash=c3444bf1fb9771db4740a58ec06dc439babe7e1b)

Now what? Am I going in the right way? I don't see how I could relate this to V_A^*.