maxenzo2
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sodium nitrate from sodium hydroxide and CAN?
what should happend with a mix of calcium ammonium nitrate and sodium hydroxide? i know it will give sodium nitrate and calcium and ammonium hydroxide
but how can i get the sodium nitrate out? the solution just turnet into a white milk color,i cant heat the solution because i dont have a hot plate.
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Amos
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Unless you used the precise amount of reagents needed to fully react, you might not be in such good shape. An excess of CAN would probably be better
than one of NaOH, but you'll most likely have hygroscopic impurities either way. If you've used the correct amounts, filter out the CaOH. Then, if
you've got glassware to heat the solution in, I would be tempted to say just use a kitchen stove burner to drive out as much ammonia as possible, but
then you've got ammonia all over your house. You can buy a really cheap kitchen-type hot plate online for $15-25, which I would strongly recommend.
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maxenzo2
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I was thinking of bubbling air through the solution to remove ammonia,but im not sure co2 from air will react with calcium hydroxide and make calcium
carbonate,do you think it could work?
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Dr.Arz
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It will form some carbonate, but it should be very easy to filter out apart from calcium hydroxide which are both nearly insoluble to water. How will
bubbling air through it remove ammonia? A good idea if you have, is to slowly heat to boil the reaction in a closed pot where you insert tube and lead
the fumes into cold water, this way ammonia goes into it and not in your room air.
5Ca(NO3)2•NH4NO3•10H2O dissolved in water with NaOH should form calcium hydroxide which quickly precipitates out, ammonium hydroxide or ammonia
water and sodium nitrate. You should determine that the CAN is pure and calculate molar ratios and then mix them in water and bring it to boil and
lead the ammonia away, and you should be left with milky solution that contains all the Ca(OH)2, which you either settle and decant or filter
out(basicity may eat some filters), and when you have crystal clear liquid, you can evaporate it to yield somewhat pure NaNO3, if you did everything
right.
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blogfast25
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Dr.Arz is more or less correct but I would suggest two improvements: get rid of the ammonia by dry distillation. Mix powdered CAN with NaOH in a
closed container acc.:
5Ca(NO3)2.NH4NO3.10H2O + 6 NaOH and add a small amount of water to help mixing it.
NH3 will now be generated acc.: NH4NO3 + NaOH === > NH3 + H2O + NaNO3
Heat gently if necessary to evolve the last bits of NH3.
Capture the NH3 in water as Dr.Arz suggested, until NH3 evolution more or less stops.
The solubility of NaNO3 at 100 C is 140 g/100 g (Wiki), so add a calculated amount of water, mix and boil. As luck would have it Ca(OH)2 is even less
soluble in hot water than cold.
Hot filter the slurry to eliminate the Ca(OH)2.
Because the solubility of NaNO3 at 0 C is only 73 g/100 g (Wiki), on chilling about half of the NaNO3 will crystallise out. With a second
crystallisation your NaNO3 should be reasonably pure.
[Edited on 19-10-2014 by blogfast25]
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Amos
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Definitely don't ignore the advice of those above; bubbling carbon dioxide into your solution will also give you ammonium carbonate in solution, which
is a whole new problem. If you combine your sodium hydroxide and calcium ammonium nitrate both in dry form and on an ice bath and slowly add a small
amount of water or ice(just enough to wet all of the powder); this should drive out nearly all of the ammonia without any dissolving, as it will get
quite hot.
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maxenzo2
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Ok guys im trying to figure it out how to calculate the moles of 5Ca(NO3)2•NH4NO3•10H2O,before i do anything,im trying to find the moles.
I came up with 1026,449 g/mol,is this right? because after that i searched to be sure using this site calculator,and it gives this 2121.4198 g/mol,i dont know who is right? or are both wrong?
i still wont do anything till i get my hot plate,but im just trying to make sure about the quantities.
[Edited on 23-10-2014 by maxenzo2]
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MrHomeScientist
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Well, let's break it down by ions (I like to round to the nearest integer):
Ca(NO3)2*NH4NO3*10H2O
Ca = 40
NO3 = 62
NH4 = 18
H2O = 18
(1 * 40) + (3 * 62) + (1 * 18) + (10 * 18) = 424 g/mol
You don't include the 5 yet; that appears later in the stoichiometry when you're trying to figure out how much of each reactant you need.
So for example if you had 10 grams of calcium ammonium nitrate (CAN), you would need:
(10 g / 1) * (1 mol CAN / 424 g) * (6 mol NaOH / 5 mol CAN) * (40 g / 1 mol NaOH) = 1.13g NaOH
Of course NaOH is hygroscopic and often contaminated with carbonate, so in practice I usually add something like 10% extra hydroxide.
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blogfast25
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No, no. You DO account the 5. CAN is a double salt of 5 mol Ca(NO3)2, 1 mol NH4NO3 and 10 mol hydrate water.
So the molar mass of CAN is 5 times the molar mass of calcium nitrate plus the molar mass of ammonium nitrate plus 10 times the molar mass of water.
That gives me a 1080 g/mol.
Per mol of CAN, you'll need 11 mol of NaOH (stoichiometrically) to covert all Ca to Ca(OH)2 and all ammonium to ammonia. So 11 mol x 40 g/mol = 440 g
NaOH.
A kg of CAN would roughly yield 24 L (STP) of NH3.
http://en.wikipedia.org/wiki/Calcium_ammonium_nitrate
Now be a good lad and start with 100 g of CAN, to see if you can do it. 
[Edited on 23-10-2014 by blogfast25]
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maxenzo2
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Quote: Originally posted by blogfast25  |
No, no. You DO account the 5. CAN is a double salt of 5 mol Ca(NO3)2, 1 mol NH4NO3 and 10 mol hydrate water.
So the molar mass of CAN is 5 times the molar mass of calcium nitrate plus the molar mass of ammonium nitrate plus 10 times the molar mass of water.
That gives me a 1080 g/mol.
Per mol of CAN, you'll need 11 mol of NaOH (stoichiometrically) to covert all Ca to Ca(OH)2 and all ammonium to ammonia. So 11 mol x 40 g/mol = 440 g
NaOH.
A kg of CAN would roughly yield 24 L (STP) of NH3.
http://en.wikipedia.org/wiki/Calcium_ammonium_nitrate
Now be a good lad and start with 100 g of CAN, to see if you can do it.
[Edited on 23-10-2014 by blogfast25] |
it works,but for some weird reason the solution didnt got hot,i used just a little bit of water,ammonium hydroxide still was formed,but at that time
it was late so i let it outside to heat up in the morning,and the smell of ammonium hydroxide was out it as evaporated,i heated the solution to be
sure and filtrate,removed the most of calcium hydroxide i could,put it into to the freezer and i got sodium nitrate crystals,still has a small amount
of calcium hydroxide but its very little.Since im not using the nitrate to make pyrotechnics its ok  thx for the help guys.
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