Re: molarity

On Tue, 26 Jul 2005 19:47:29 +0200, Craig <cagerken@xxxxxxx> wrote:

So if, in a solution, we have 3 M Na+ and 1 M CO3- is the molarity of this
solution:

2 M:  1 M Na2CO3 + 1 M Na+ that is left = 2M
or
1 M: because Na2CO3 is the only thing I should considered


Neither, really.  You seem to have an idea that "molarity" is a
property that can be applied to a solution as a whole.  If you had a
complicated mixture of many solutes, like, say, seawater or blood, you
would rarely say "this is a 2.0 M solution", as if that encompassed
everything.  There are times when it is useful to know the total
concentration of every blessed thing in solution.  Most often, we speak
of the concentration of a specific component.

To add to that: JD, take a look at the bottle of mineral water, they have sometimes concentrations of dissolved ions given (in mg/L, but it doesn't matter) - every ion concentration is given separately, asi it doesn't matter what was dissolved to obtain the final effect.

Best,
Borek
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