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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Neilb75 on August 13, 2007, 10:14:08 PM

Title: Ionic solutions and Total dissolved solids
Post by: Neilb75 on August 13, 2007, 10:14:08 PM
I have a question regarding a solution of CaCl2. I have formed the solution by adding anhydrous calcium chloride to pure water. I understand that the solubility will increase with an increase in temperature. I created the solution at a temperature of 80F. The solution created contains 2500ppm of total dissolved solids. This is a weak solution, far from being saturated.
My question is, if I increase the temperature of this solution of CaCl2 what happens to the existing concentration of ions?? Will heat effect the concentration of Ca and Cl ions?? If so how?
Heat increases the conductivity of the solution rendering the TDS meter reading inaccurate to determine if there is an increase in the concentration of ions.

Many thanks
Title: Re: Ionic solutions and Total dissolved solids
Post by: shelanachium on August 15, 2007, 04:56:47 PM
A solution this dilute should be completely ionised to Ca2+ and Cl- ions, and heating it should therefore have no influence on the concentration of ions.
Title: Re: Ionic solutions and Total dissolved solids
Post by: rkaminski on August 18, 2007, 04:43:16 PM
Well, actually heating will have influence on the concentration. Volume of solution is dependent on temperature. Of course this effect will be almost negligible:)
Title: Re: Ionic solutions and Total dissolved solids
Post by: Borek on August 18, 2007, 05:29:02 PM
Well, actually heating will have influence on the concentration. Volume of solution is dependent on temperature. Of course this effect will be almost negligible:)

It all depends on the concentration type. Molality is not temperature dependent. In fact it is often used just to avoid this type of problems.