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#Post#: 1011--------------------------------------------------
Properties of Ammonium carbonate
DIR By: Shiva
Date: October 28, 2012, 1:05 pm
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HTML https://www.youtube.com/watch?v=sDXVEYleZAc
#Post#: 1033--------------------------------------------------
Re: Properties of Ammonium carbonate
DIR By: Chris
Date: November 1, 2012, 9:05 am
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Nice video again!
If i may ask, how stable is ammonium carbonate?
#Post#: 1035--------------------------------------------------
Re: Properties of Ammonium carbonate
DIR By: Shiva
Date: November 2, 2012, 7:32 am
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Thank you Chris. Yes, it is not extremely unstable like
Aluminium carbonate or Magnesium sulfide. The stability of
Ammonium carbonate can be compared to Ferrous sulfate. It is
slowly decomposed into Ammonium bicarbonate, Ammonium carbamate
and Ammonia. Likewise, Ferrous sulfate undergoes auto-oxidation
and ends up with a mixture of Ferric oxide & Ferric sulfate. If
you see the attached picture (my lab sample), can you believe it
is Ferrous sulfate? actually it is hahaha. But, still it is not
completely oxidized. Nevertheless, I should buy a new box in a
month or so. These sort of compounds cannot be stored for a long
time. Better you use them in less than a year before they
decomposed completely. Still, it depends on how you stored these
compounds. They may last for few more months if you stored in a
well air tight container.
Shiva
#Post#: 1036--------------------------------------------------
Re: Properties of Ammonium carbonate
DIR By: Michel
Date: November 2, 2012, 9:12 am
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Ammonium carbonate would typically decompose at stp via two
pathways.
1. The familiar spontaneous decomposition of Ammonium carbonate
to NH3 and NH4HCO3
(NH 4 ) 2 CO 3 ¡ú NH 4 HCO 3 + NH 3.
It will also react with oxygen at RT to give ammonium carbamate
and water
(NH 4 ) 2 CO 3 + O 2 ¡ú NH 4 CO 2 NH 2 + H 2 O
Hence your 'pure' ammonium carbonate will soon become a mix of
these compounds :P
#Post#: 1045--------------------------------------------------
Re: Properties of Ammonium carbonate
DIR By: Michel
Date: November 2, 2012, 6:30 pm
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My experience with Ferrous compounds is limited, and only the
common ones I've handled, but my experience with them is similar
to yours Shiva. Infact, I've had an awful experience with them
cos I'm lazy when it comes to storage 8-)
Usually, they don't last more than a week for me (I don't like
large quantities). And then knowing how pure the sample is? How
much Fe2+ has been converted to Fe3+ isn't the easiest thing to
do ;)
--- Quote from: Shiva link ---
>
> They may last for few more months if you stored in a well air
tight container.
>
> Shiva
>
--- End Quote ---
Really? I'm thinking of an air tight jar, lined with a greasy
coat of a compound that can be selectively oxidized, and slowly
too :)
#Post#: 1047--------------------------------------------------
Re: Properties of Ammonium carbonate
DIR By: Shiva
Date: November 3, 2012, 1:20 pm
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haha. Well, we can't come to any conclusion by just noted its
appearance and also we are not sure how much Fe2+ is converted
to Fe3+. However, we can find which ion is dominating by adding
Sodium hydroxide or ammonium hydroxide. Of course, it is the
usual test for precipitating hydroxide. Ferrous sulfate
precipitates green Ferrous hydroxide on adding Sodium or
Ammonium hydroxide. If it turns red and precipitates Ferric
hydroxide, it means , it is almost or completely oxidized Fe3+
ion. Then we have to go for the new sample. That's why we have
been asked to use freshly prepared ferrous sulfate solution for
brown ring test.
Shiva
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