RATES Calcite-start 1 REM PARM(1) = specific surface area of calcite, cm^2/mol calcite 2 REM PARM(2) = exponent for M/M0 10 si_cc = SI("Calcite") 20 IF (M <= 0 and si_cc < 0) THEN GOTO 200 30 k1 = 10^(0.198 - 444.0 / TK ) 40 k2 = 10^(2.84 - 2177.0 /TK ) 50 IF TC <= 25 THEN k3 = 10^(-5.86 - 317.0 / TK) 60 IF TC > 25 THEN k3 = 10^(-1.1 - 1737.0 / TK ) 80 IF M0 > 0 THEN area = PARM(1)*M0*(M/M0)^PARM(2) ELSE area = PARM(1)*M110 rate = area * (k1 * ACT("H+") + k2 * ACT("CO2") + k3 * ACT("H2O"))120 rate = rate * (1 - 10^(2/3*si_cc))130 moles = rate * 0.001 * TIME200 SAVE moles-endENDPHASESFix_H+ H+ = H+ log_k 0ENDSOLUTION 1 temp 25 pH 6 pe 4 redox pe units mmol/kgw density 1 C 1 Calcite -2.3 Ca 1 -water 1 # kgENDKINETICS 1Calcite -formula Calcite 1 -m 4.5 -m0 4.5 -parms 100 1 -tol 1e-08-steps 86400 in 10 steps # seconds-step_divide 1-runge_kutta 3-bad_step_max 500USE solution 1EQUILIBRIUM_PHASES 1 CO2(g) -1.54 10 Fix_H+ -6 HCl 10USER_GRAPH 1 -axis_titles "Time, days" "Calcite dissolved, mmol" "" -initial_solutions false -connect_simulations true -plot_concentration_vs x -start10 GRAPH_X TOTAL_TIME/(3600*24)20 GRAPH_y (4.5 - KIN("Calcite"))*1000 -end -active trueEND