Heat of dissolution given in DB: Infinite dilution?

[jungsdao]

Hello,
This might be a very basic question about the heat of dissolution..
I'd like to know whether the given heat of dissolution of minerals in database are the value at infinite dilution.
As far as I know, heat of dissolution varies with the molality of the solute species in the solution.
Is it safe to use fixed value of heat of solution for the calculation of total heat of dissolution as (heat of dissolution)x(dissolved amount) for certain amount of solute?

Many thanks...

 

[dlparkhurst]

PHREEQC databases have enthalpies of reaction at 25 C for most aqueous species and minerals. These enthalpies are used only to estimate log Ks for the reaction at temperatures other than 25 C (unless there is an analytical expression for log K, which is used instead). PHREEQC does not calculate the change in temperature of solutions due to reactions. You are on your own to determine heats of dissolution.