?The NIST Chemistry WebBook reports critically evaluated Henry’s constants for selected

Chapter 13, Problem 13.25

(choose chapter or problem)

The NIST Chemistry WebBook reports critically evaluated Henry’s constants for selected chemicals in water at \(25^{\circ} \mathrm{C}\). Henry’s constants from this source, denoted here by \(k_{H i}\) appear in the VLE equation written for the solute in the form:

\(m_{i}=k_{H i} y_{i} P\)

where \(m_{i}\) is the liquid-phase molality of solute species i, expressed as mol i∕kg solvent.

(a) Determine an algebraic relation connecting \(k_{H i} \text { to } \mathcal{H}_{i}\), Henry’s constant in Eq. (13.26). Assume that \(x_{i}\) is “small.”

(b) The NIST Chemistry WebBook provides a value of 0.034 \(\mathrm{mol} \cdot \mathrm{kg}^{-1} \cdot \mathrm{bar}^{-1}\) for \(k_{\mathrm{Hi}} \text { of } \mathrm{CO}_{2} \text { in } \mathrm{H}_{2} \mathrm{O} \text { at } 25^{\circ} \mathrm{C}\). What is the implied value of \(\mathcal{H}_{i}\) in a bar? Compare this with the value given in Table 13.2, which came from a different source.

Text Transcription:

25^circ C

k_Hi

m_i=k_Hi y_iP

m_i

k_Hi to H_i

x_i

mol cdot kg^-1 cdot bar^-1

k_Hi of CO_2 in H_2O at 25^circ C

H_i