Difference between revisions of "X-based and m-based activity coefficients in the solver"

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(Created page with "On the molality basis, the activity coefficient of water is undefined (it is defined for all components except water). Therefore, we report directly the activity of water in t...")
 
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On the molality basis, the activity coefficient of water is undefined (it is defined for all components except water). Therefore, we report directly the activity of water in the γ–m-based column. Water is the only exception (because of the definition of molality, which refers everything to 1 kg of water). For all other components, we report the activity coefficients. On the mole fraction scale, there are no such exceptions because water is then treated as any other component and the γ–x-based column shows activity coefficients for all species, including water. So, xwater(x-based)γwater(x-based) = awater(x-based)=awater(m-based).
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Conversion of Activity Coefficient from molal basis to mole fraction basis
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The conversion from the activity coefficient in molal basis (i.e. unsymetric) to mole fraction basis (i.e. symmetric) is the following:
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γ_(K^+)^(m,∞)=x_w^x∙γ_(K^+)^(x,∞)
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On the molality basis, the activity coefficient of water is not defined (it is defined for all components except water). This is because the definition of molality, which refers everything to 1 kg of water. For all other components, we report the activity coefficients. Therefore, we report directly the activity of water in the γ–m-based column.
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On the mole fraction scale, there are no such exceptions because water is then treated as any other component and the γ–x-based column shows activity coefficients for all species, including water.
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So,
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x_w^x∙γ_(K^+)^x=a_(K^+)^x=a_(K^+)^m

Revision as of 08:47, 26 June 2018

Conversion of Activity Coefficient from molal basis to mole fraction basis The conversion from the activity coefficient in molal basis (i.e. unsymetric) to mole fraction basis (i.e. symmetric) is the following: γ_(K^+)^(m,∞)=x_w^x∙γ_(K^+)^(x,∞)

On the molality basis, the activity coefficient of water is not defined (it is defined for all components except water). This is because the definition of molality, which refers everything to 1 kg of water. For all other components, we report the activity coefficients. Therefore, we report directly the activity of water in the γ–m-based column. On the mole fraction scale, there are no such exceptions because water is then treated as any other component and the γ–x-based column shows activity coefficients for all species, including water. So, x_w^x∙γ_(K^+)^x=a_(K^+)^x=a_(K^+)^m