[micky]

Hello everyone!

Does anyone of you know how to determine the content of EACH compound in the mixture: CaCO3, Ca(OH)2 and a moisture?

If someone does, I'd love you to explain me how to do it

[Borek]

You have to show your attempts before receiving help, this is a forum policy.

Many ways to skin that cat, depending on what you know, so there is no one, general answer.

[micky]

I'm not sure whether it is a good way but I would use acid-base titration using two indicators. I'd take hydrochloric acid with phenolphthalein and I could titrate calcium hydroxide and calcium carbonate and next I can add methyl orange and continue the titration of the remaining part of CaCO3. Nevertheless, like I said it is just my wild guess.

[Arkcon]

You have guess upon the typical method.  There may be others depending on how many sample you have, and to what level you need the answer.  There is also a quite famous titration method for moisture.  Its a tricky procedure, using specialized equipment, and again, we need to know -- how good of an answer do you need and why, and what your technical level is.

[micky]

Okay. I've got both CaCO3 and Ca(OH)2 in the amount of macro (quite a lot). I think the best way to determine the contents is by using a classic analysis (titrations etc.) Is there any better classical way to determine it (than the one I have mentioned)? If not, how should I start the procedure of determining it in the way I've mentioned? Should I dissolve CaCO3 and Ca(OH)2 first in something? If yes, what should I dissolve it in?

[Borek]

CaCO₃ solubility is quite low (Ksp around 3×10^-9), so while the Warder method sounds plausible in principle, it will be probably impossible to do.

I would try total calcium (after dissolving sample in HCl) and separately Ca(OH)₂ in filtrate.

[micky]

But how can you separate Ca(OH)2 from CaCO3? Both of them after dissolving will be in a solution.

[Corribus]

I would use thermogravimetric analysis. Your components decompose at significantly different temperatures.

[Borek]

But how can you separate Ca(OH)2 from CaCO3? Both of them after dissolving will be in a solution.

Ca(OH)₂ is much more soluble, so - if the sample mass and volume are carefully selected - it can be possible to dissolve just the hydroxide, leaving CaCO₃ as a solid; I can be wrong though.