What happened to my ground eggshell? page

[breadsauce]

I have collected, washed and dried several eggshells. I ground them a fine powder and put a teaspoonful in a small mug and added the juice of a lemon. So far, so good - I like to stir it into soup. After about 6 hours it had pretty well dissolved.

Well, I forgot to add it to my soup. So it sat on the counter for over 24 hours. And this morning, to my amazement, a lot of "solids" had reappeared - FAR more than the original teaspoon of eggshell powder. Stirring didn't make it dissolve again, and in the end I tipped it onto my compost heap.

Anyone done this? Or have any ideas what happened? I am mystified....

[sakura_girl]

Calcium citrate salts?

In chemistry when you have an acid and a base added together, after they react with each other you get an insoluble salt and water. Sometimes.

[DubleYoo]

Yep, like sakura_girl said, it's calcium citrate.
3 CaCO3(s) + 2 C6H8O7(aq) ----> Ca3(C6H5O7)2(s) + 3 CO2(g) + 3 H2O(l)
Calcium carbonate in eggshells reacts with citric acid in lemon juice to create calcium citrate, carbon dioxide, and water. Calcium citrate is mostly insoluble in water.

[Danielle5690]

Cool science experiment!

[sakura_girl]

Man this makes me miss chem so bad ((((

It used to be my best subject, even ahead of physics (but behind math XD).

[healthy11]

You smart chemistry people! Interesting!

[DubleYoo]

The only thing better than chemistry is biochemistry. And astronomy. And physics. And astrophysics. And general biology.

Nevermind, no science is better than any other. They're all so good. And rather interrelated anyway.

[peril]

All science is either physics or stamp collecting - Ernest Rutherford

[breadsauce]

So - can I eat the resulting stuff, or is it a matter of using the lemon juice / eggshell when it is actually first dissolved? Or is there a BETTER way of using the ground eggshell?!

[DubleYoo]

So - can I eat the resulting stuff, or is it a matter of using the lemon juice / eggshell when it is actually first dissolved? Or is there a BETTER way of using the ground eggshell?!

Either way is fine. I don't know how else you'd use eggshell other than omitting the lemon juice. Calcium citrate is sold as a supplement, and the eggshell (and everything) reacts with the acid in your stomach anyway. Digestion depends on it!