Ch. 5. ACTIVITY COEFFICENTS OF DISSOLVED SPECIES. 5-1. Introduction What is activity of a dissolved species? Effective concentration Equivalent to the concentration acting in effect Why do we need activity (or have activity)? Interactions among the dissolved matter
Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.
Debye-Hückel limiting law (DHLL)
When I <0.001: eqn (4.30) on p.129
Extended Debye-Hückel equation (EDHE)
When I<0.1: eqn (4.28) on p.128
A=1.824928*106ro1/2(eT)-3/2, 0.5092 (at 25C)
B=50.3(eT)-1/2, 0.3283 (at 25C)
Table 4.1 for effective ionic radii on p.130
Fig. 4.3 on p.132
Other equations for higher I
Davies et al.; eqn (4.31) on p.132
Trusdell & Jones (1974)
Bronsted-Guggenheim-Scatchard specific ion interaction theory (SIT) equaton: eqn (4.32) p.133
Fig. 4.4. p.135.
Pitzer model; eqn (4.49) p.138
All interactions are not purely ionic
Ions are not point charges
Ion size varies with I
Ions do interact w/ other ions and even with the same species
In most cases, approximately g=1
Generally follow Setchenoweqn (Lewis & Randall, 1961)
Log gi = KiI, where Ki = 0.02 ~ 0.23
Table 4.5 on p.144.