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Beginners => PHREEQC basics => Topic started by: ehsan on June 01, 2021, 02:12:48 PM

Title: calculation the analytical
Post by: ehsan on June 01, 2021, 02:12:48 PM
hi dears
excuse me,
How does phreeqc calculate the analytical in PHASES when we commented that with #?


Code: [Select]
DATABASE C:\Program Files (x86)\USGS\Phreeqc Interactive 3.7.0-15749\database\phreeqc.dat
# DATABASE c:\phreeqc\database\llnl.dat # has S5- etc species
# Compare expt data of H2S solubility at high H2S pressure and
#   Peng-Robinson calc's with initial solution equilibria.

PHASES
H2S(g)
H2S  =  H+ + HS-
log_k    -7.97
-delta_h   9.1
# -analytic -9.7354e+001 -3.1576e-002 1.8285e+003 3.7440e+001 2.8560e+001
-T_c  373.2
-P_c  88.2
-Omega 0.1
SOLUTION 1
 pH 7 charge
 S(-2) 1# H2S(g) 0
SELECTED_OUTPUT; -reset false; -file H2S_71.prn
USER_PUNCH
  1 sc$ = chr$(59)
 10 for i = 1.1 to 220 step 5
 20   punch 'SOLUTION 1' + sc$ + ' -temp 90' + sc$ + ' pH 3 charge' + EOL$ + 'S(-2) 1 H2S(g) ' + str$(log10(i)) + EOL$ + '-pressure ' + str$(i) + EOL$ + 'END' + EOL$
 30 next i
END

SELECTED_OUTPUT 1; -active false
PRINT; -reset false; -echo_input true
USER_GRAPH
 -plot_csv_file h2s2.tsv
 -axis_titles "Pressure / atm" "H2S / (mol/kgw)" " phi_H2S"
 -axis_scale x_axis 0 210
 -initial_solutions true
 10 x = PR_P("H2S(g)")
 20 graph_x x # tot("Na")
 30 graph_y tot("S(-2)")
 40 graph_sy PR_phi("H2S(g)") #mol("H2S") / tot("S")
 -end
INCLUDE$ H2S_71.prn
END
Title: Re: calculation the analytical
Post by: dlparkhurst on June 01, 2021, 02:32:42 PM
The Van't Hoff expression with delta H is used if -analytical is not defined.