Henrian activity

Find Henrian activity coefficient, Yq of liquid Fe-C solutions at 1,600°C. 

It is obvious from the equation that the activity coefficient of A at infinite dilution of A, i.e., the Henrian activity coefficient, yA° is given by... 

The numerical value of the activity of j at the Henrian standard state is 1 on the Henrian activity scale, but y° on the Raoultian activity scale. 

The activity of silicon in a binary Fe-Si liquid alloy containing Nsl = 0.02 is 0.000022 at 1,600°C relative to the Raoultian standard state. The Henrian activity coefficient y% is experimentally determined to be 0.0011. 

Fugacity, also see below f = Henrian activity coefficient F = Free Energy, Gibbs Free Energy F = Farady Constant g = Gas... 

Single ion activities should be used for components where the activities are expressed in terms of the ideal dilute solution as the standard state (Henrian activities). 

This standard state is so defined that the Henrian activity approaches the atom fraction at infinite dilution, i.e. 

Assuming that the solution obeys Henry s law up to 1 wt % of A, then h is unity at this concentration, and thus the standard state is the 1 wt% solution. Deviations from this equality of activity and weight percent are measured in terms of Henrian activity coefficient relative to the infinitely dilute, weight percent standard state, i.e. 

Though in both the equations (6.27) and (6.30) h and f have been used for denoting the Henrian activity and activity coefficient of A respectively, in Eq.(6.27) they signify relative to the infinitely dilute, atom fraction standard state, while in Eq.(6.30) they are relative to the infinitely dilute, weight percent standard state. 

Here, y ° is called the Henrian activity confident, and its value is 1. 

Using these K values calculated for cerium oxides, sulfides, and oxysulfides, Wilson et al. (1974, 1976) have constructed an inclusion precipitation diagram for the Fe-Ce-O-S system (fig. 4), where hct, ho and hs represent the Henrian activities of cerium, oxygen and sulfur, respectively. This composite precipitation diagram gives a clear, qualitative picture of the conditions of phase formations and transformations. 

In these expressions Y and v refer to the solute species and X and x to the solvent Nx and Yy are the mole fractions. With ntot as the total number of moles and y the number of moles Y, b an interaction parameter of the system, y the activity coefficient, and a Henrian activity coefficent, the equation for the partial molar heat of mixing is derived as... 

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