DATABASE C:\Program Files\USGS\Phreeqc Interactive 2.6\phreeqc.dat
# R.5. Exercise
SOLUTION_SPREAD
 Description	 Temp	  pH	       O(0)	    Ca	    Mg	    Na	     K	    Cl	 S(6)	        C(4)	  N(5)	 N(-3)
           	     	    	 O2(g) -0.7	      	      	      	      	      	     	 CO2(g) -3.5	      	      
   Rainwater	   25	 4.5	          1	 0.384	 0.043	 0.141	 0.036	 0.236	  1.3	           1	 0.237	 0.208
END
MIX 1
    1    20
REACTION
	H2O	55.5
	-19 moles
EQUILIBRIUM_PHASES
	CO2(g)	-3.5
SAVE solution 2
END
USE solution 2
EQUILIBRIUM_PHASES 2
    Calcite   0 10
    CO2(g)    -2 10
SAVE solution 3
END
USE solution 3
REACTION 1
    CO2        1
    1 millimoles
EQUILIBRIUM_PHASES 3
    Calcite   0 10
SAVE solution 4
END