The REACTION data block is an independent definition that does not use information from RATES or KINETICS. REACTION simply specifies a number of moles of reactants to be added to a solution. In your example, REACTION would add .001 mole Ca, 0.001 + 2*.001*55.5 mole H, and .001*55.5 mole O to solution 9. However, you should use the formula Ca(OH)2 to have a charge balanced reactant. Normally, I would not add the water with REACTION. If it is a mixing of solutions, I would define two solutions and use the MIX data block. KINETICS requires a corresponding RATES definition. The reaction that is added is defined with the -formula identifier in KINETICS and the rate expression is defined in RATES. The rate expression is defined once in RATES, but could be used by multiple KINETIC data blocks. You are adding your reaction twice by including both KINETICS and REACTION.I do not include the water in the reaction. You are removing reactants with a negative number of moles, which would imply you are removing water from the system. I don't think this is what you want to do. The rate expression indicates you will remove all alkalinity by precipitating Ca(OH)2, which does not make much physical sense. You will run into a problem if there is not enough calcium to balance the alkalinity. I have not run this because I think there are too many conceptual problems, but the following at least shows the basic connection between RATES and KINETICS. RATES Ca(OH)2 -start 1 rem M = current number of moles of Ca(OH)2 2 rem M0 = number of moles of Ca(OH)2 initially present 10 if (pH >= 6.0) then goto 200 15 M = - ALK*0.5 20 rate = M 30 moles = rate * TIME 200 SAVE moles -end END KINETICS 1 Ca(OH)2 -formula Ca(OH)2 1.0 # -m0 0.0 # -m 0.0 #MOL("CaOH") END USE solution 9 USE kinetics 1 END David David Parkhurst (dlpark@xxxxxxxx) U.S. Geological Survey Box 25046, MS 413 Denver Federal Center Denver, CO 80225 "Bernd Ehret" <ehbernd@xxxxxx> To: "David L Parkhurst" <dlpark@xxxxxxxx> cc: In-Reply-To: <004301c16ce2$ea453f60$9546ddd5@xxxxx> 11/14/01 01:03 Subject: Re: bernd 14-11-01 AM In the file above I send you my problem with RATES in connection with KINETICS or REACTION: In RATES I want to use the value of alkalinity (negative ALK) to produce moles for the KINETICS or REACTION. Specially in the lines ... ... RATES CaOH -start 1 rem M = current number of moles of calcite 2 rem M0 = number of moles of calcite initially present 10 if (pH >= 6.0) then goto 200 15 M = - ALK 20 rate = M 30 moles = rate * TIME 200 SAVE moles -end END REACTION 1 CaOH(H2O)55.5 1.0 ??? mmol #??? How come the moles from RATES to KINETICS or REACTION? END KINETICS 1 CaOH 1.0 H2O 55.5 # -m0 0.0 # -m 0.0 #MOL("CaOH") END How come the moles from RATES to KINETICS or REACTION? And I don't understand the right connection between moles in RATES and moles in KINETICS or REACTION. Please, can you help me? Bernd(See attached file: CaOH_kinetics.in)
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