99.5% acetic acid with calcium

[elias1]

i am not much of a chemist
a couple of days ago i bought acetic acid 99.5%, calcium carbonate 98.5% USP grade and kalkwasser and my oolitic sand from my reef tank.

in 3 different cups i added a 1tsp of each of the calcium product above
and 1tsp of the acidic acid into each cup

few hrs later :arrow:

calcium carbonate no changes
kalkwasser all desolved with enough acid to dessolve more
reef sand desolved with enough acid to dessolve more

why did the calcium carbonate not dessolve :?: :?:

 

[Anonymous]

Surface area maybe???

 

[liquid]

calcium carbonate 98.5% USP grade

You sure you got calcium carbonate? It should have dissolved.

Shane

 

[elias1]

yes it is CaCo3
bought it from a chemical and food grade lab

 

[liquid]

Did any of it dissolve? Have you re-run the test?

Shane

 

[elias1]

i have repeated the test few times over the same results

all this is to have more calcium into my reef
well how about acidic acid and reef sand would that not be almost the same end result as using calcium reactor

 

[Anonymous]

Does the carbonate even generates CO2 bubble? If not, you might got the wrong stuff :?

 

[RWillieK]

If you're adding the CaCo3 last, the acetic acid may have been nuetralized already.

 

[RobertoVespucci]

Is your CaCO3 in powder, granules, chunks? Did you try stirring? I would have expected the reaction to be somewhat vigorous.

 

[Anonymous]

Try measuring the increase in calcium when just using the calcium carbonate. And measure the ph as well.

 

[liquid]

Reef Box Etc: Does the carbonate even generates CO2 bubble? If not, you might got the wrong stuff

RBE hit the nail on the head. If it doesn't bubble or fizz when you add the two together, you don't have calcium carbonate.

Shane

 

[elias1]

late last night i gave up and was in the process of throwing the cups in the sink with water to wash away.

some water got into the cup that contains CaCo3 and acidic acid and gess what it was foaming and fising like crasy.
so i retested the method water CaCo3 powder acidic acid and it worked

my next step is to check the ratio of CaCo3 water to acidic acid and have a clear solution with a Ph of near reef water levels to go into my reef

 

[Anonymous]

I could be wrong but I seem to remember that a 50% solution of Acetic acid is actually stronger than 100%.

 

[Anonymous]

late last night i gave up and was in the process of throwing the cups in the sink with water to wash away.

some water got into the cup that contains CaCo3 and acidic acid and gess what it was foaming and fising like crasy.
so i retested the method water CaCo3 powder acidic acid and it worked

my next step is to check the ratio of CaCo3 water to acidic acid and have a clear solution with a Ph of near reef water levels to go into my reef

From what I hear calcium carbonate will dissolve at ph's less that 8.2 or so. And as it dissolves the ph comes up. the closer the ph is to 8.2 the slower the calcium carbonate dissolves until it stops dissolving.

So no surprise here. The would even be some dissolving if you just use water with a ph of 7.0. Just works faster with a lower ph.

 

[Anonymous]

From what I hear calcium carbonate will dissolve at ph's less that 8.2 or so. And as it dissolves the ph comes up. the closer the ph is to 8.2 the slower the calcium carbonate dissolves until it stops dissolving.

So no surprise here. The would even be some dissolving if you just use water with a ph of 7.0. Just works faster with a lower ph.

You totally lose me there, PLB. I think one important issue that you miss about dissolution/disolving is that it is not just pH dependent as you think (well, as far as I can tell from most of your posts). Rather calcium carbonate dissolves in seawater/solvent depends on pH AND the calcium concentration on the solvent. Your pH value above has to do with seawater, and it is different for RO/DI water, etc., due to the different ions already in the solvent.

As to why the calcium carbonate need the addition water to bubble, but the aragonite does not is not obvious to me. I can use some explaination like insufficient water ions (H+ and OH-) in the concentrated acetic acid to let you see the CO2 (foam) and immature ending of the reaction due to the fast approach to equilibrium (chemists call the water in this case the "limiting reagent"). But this does not hold water in your observation due to the bubbling of the other two items.

:?

 

[VanReef]

One thing about using vinegar is that it leaves behind a lot of dissolved organics (acetate) that will fuel bacterial growth.

Also vinegar is not usually very concentrated. (4-5%). You have to add quite a bit in order to neutralize something like limewater.

Have you considered muriatic (hydrochloric) acid instead?

 

[Anonymous]

He used 99.5% acetic acid (I think chemists call it "glacial acetic acid," but not too sure). HCl will work great, and it is what pool service people used to clean off scale (Ca and Mg carbonate, mainly).