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**Unformatted text preview: **of a solution of, say, two miscible liquids is given by
V = n1 V1 + n 2V2. (5.33) The units of partial molar volumes are the same as molar volumes. The
relationship between the two, i.e., partial molar volume and the molar volume is a
subtle but important one.
In the case of ideal solutions, the partial molar volume of each component will
be identical to the molar volume of the pure substance in the absence of the
other component. However, in the case of non-ideal solutions, the presence of the second
component has a measurable influence on the molar volume of the first
component and vice versa. Therefore, in general,
V 1 ! V and V 2 ! V .
2
1 The standard state for defining partial molar quantities is a 1 molal solution, i.e., a
solution that contains 1 mol of the substance in 1.0 kg of solvent. Physical Interpretation of partial molar quantities:
It may appear that there is something “not quite right” about the following two
equations:
V = n 1 V 1 + n 2 V 2 , where
, and V 2 = æ ¹V ö
.
V 1 = æ ¹V ö
ç ¹n ÷
ç ¹n ÷
è 1 ø P, T , n 2
è 2 ø P, T , n 1
Based on what we have seen so far, the first equation shoul...

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