Calculation of partial molar quantities from experimental data

Calculation of partial molar quantities from experimental data 

The most useful partial molar quantities are those which occur in equations (2 111) and (2-113), namely, the volumes and enthalpies. These may be computed from the volume change on mixing the pure components and from the corresponding absorption of heat at constant pressure, equal to the enthalpy increase on mixing. One of the methods will ye discussed briefly for the case of two components. 

Let hi and the enthalpies per mole of the two pure components and let Hi and H2 be the partial molar enthalpies in a solution containing ni moles of component 1 and moles of component 2. Then the heat absorbed at constant pressure in making this mixture is 

The heat absorbed per mole will be denoted by M and is obtained by dividing through by (Wi+ng)  

At a particular mole fraction, the gradient CD of the curve is obtained from (2 119) asf 

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