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Ramium
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Quote: Originally posted by TheAustralianScientist  | | Quote: | sorry i am new to chemistry. I will just use the 500 /l stuff then.
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No need to apologize. Everyone started at some point and I think SOME people need to remember that.
I think you could use the 5.1M stuff. You'll just need to recalculate the stoichiometry. Would you like me to show you how?
I gather you're planning on making Copper(II) Phosphate? Not Copper(I) Phosphate?
[Edited on 2-2-2015 by TheAustralianScientist]
[Edited on 2-2-2015 by TheAustralianScientist] |
Yes copper 2 phosphate. Could you tell me how many ml of phosphoric acid (5.1M) and how many grams of copper carbonate???
Thanks
[Edited on 2-2-2015 by Ramium]
[Edited on 2-2-2015 by Ramium]
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gdflp
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That depends, how much copper phosphate do you want to synthesize? Remember, you will need to dissolve the copper carbonate in an acid such as
hydrochloric, nitric, sulfuric, acetic, etc., then add the phosphoric acid to precipitate out insoluble copper phosphate. Theoretically, to calculate
how much copper carbonate to use, first take the desired amount of copper phosphate and divide that number by the molar mass, in this case,
434.63g/mol. Then multiply the product with the molar mass of copper carbonate to determine how much is needed. In this case, that won't work
because copper carbonate has varying compositions with differing molar masses. In this case, take roughly half of the desired weight of the product
of copper carbonate and add a dilute acid until it is completely dissolved. Then add phosphoric acid slowly until no more precipitation is observed.
Filter the precipitate and wash it with water to yield copper phosphate.
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Ramium
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Sorry i'm very bad at maths and have trouble understanding this.
I need a simple equation with specific quantities which i can either use directly or change as needed if i don't have enough chemicals.
To make lets say 20 grams of copper phosphate
I have some 33% hydrochloric acid which i could use to dissolve the copper carbonate. How dilute should i make the HCl?
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Zombie
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He stated it very clearly Ramium.
Just read it thru slowly one more time.
Quote:
" In this case, take roughly half of the desired weight of the product of copper carbonate and add a dilute acid until it is completely dissolved.
Then add phosphoric acid slowly until no more precipitation is observed. Filter the precipitate and wash it with water to yield copper phosphate."
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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blogfast25
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"Maths" doesn't come into it: at worst; arithmetic.
"If 5 apples cost 39 cents, how much do 9 apples cost?"
That's the level we're talking about here. Can't do that? Go back to school.
Look up 'moles' (chemistry), 'Molar mass', get back.
[Edited on 3-2-2015 by blogfast25]
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Ramium
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Sorry just skimed threw the post.i tried the experiment i added the dilut(10%ish)HCL to the copper carbonate and got a green solution.then when i
added the phosphoric acid the solution turned blue and there was no pricipitate.you seem to imply that the copper phosphate is not soluble but the
video i posted in my second post seems to imply it is soluble i looked at copper phosphate on wikipedia and it said it is not soluble but wikipedia
can be edited by eneyone.so is it soluble??
If it is could my blue solution be a solution of copper phosphate??
[Edited on 3-2-2015 by Ramium]
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Zombie
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Here are 2 reference pages you may want to print out or convert to PDF for long term use.
The first link answers your question, and the second link explains how it is answered.
I hope they help.
http://www.solubilityofthings.com/water/ions_solubility/ksp_...
http://chemwiki.ucdavis.edu/Physical_Chemistry/Equilibria/So...
They tried to have me "put to sleep" so I came back to return the favor.
Zom.
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Ramium
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To mathematical i am only 13 and dont understand a word.i just want to know if i am looking for a precipitate or a solution
[Edited on 3-2-2015 by Ramium]
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Amos
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You're looking for a precipitate. And I'm confused how a lot of you seem to think that phosphoric acid itself is going to form a precipitate of copper
phosphate.
@blogfast Are you claiming that the copper phosphate is just going to fall out of solution into newly formed sulfuric acid? If not, what's the
equation you're going by?
I just took some of my copper phosphate(I have it on hand, having made it several times) and found that it dissolved completely and easily in dilute
sulfuric acid(about 10% concentration) to form a light blue solution. So no, I don't think that adding phosphoric acid to copper sulfate solution will
form a precipitate, and it's probably better to go with the high-yield and straightforward synthesis from sodium phosphate.
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blogfast25
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| Quote: Originally posted by No Tears Only Dreams Now |
I just took some of my copper phosphate(I have it on hand, having made it several times) and found that it dissolved completely and easily in dilute
sulfuric acid(about 10% concentration) to form a light blue solution. So no, I don't think that adding phosphoric acid to copper sulfate solution will
form a precipitate, and it's probably better to go with the high-yield and straightforward synthesis from sodium phosphate. |
Ok, your experiment shows that copper phosphate is soluble, in which case adding sodium phosphate to a Cu<sup>2+</sup> solution will of
course not precipitate copper phosphate either.
So by NTODN's information, copper phosphate is soluble.
And in that case I would dissolve the copper basic carbonate in phosphoric acid:
3 Cu<sub>2</sub>CO<sub>3</sub>(OH)<sub>2</sub> + 4 H<sub>3</sub>PO<sub>4</sub> === > 2
Cu<sub>3</sub>(PO<sub>4</sub><sub>2</sub> + 2
CO<sub>2</sub> + 8 H<sub>2</sub>O
I'll put some calcs in my next post.
[Edited on 3-2-2015 by blogfast25]
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blogfast25
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Ramium:
Take 22.1 g (0.1 mol) of copper basic carbonate and mix it with about 200 ml of water into a slurry.
Add slowly about 30 ml of the 5.1 M H3PO4 solution. Beware of fizzing, so add in small aliquots.
Simmer for a bit on a hot plate , filter if still turbid.
Slowly boil in the clear solution until the first crystals appear and allow to cool, the copper phosphate should crystallise out.
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Amos
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| Quote: Originally posted by blogfast25 | | Quote: Originally posted by No Tears Only Dreams Now |
I just took some of my copper phosphate(I have it on hand, having made it several times) and found that it dissolved completely and easily in dilute
sulfuric acid(about 10% concentration) to form a light blue solution. So no, I don't think that adding phosphoric acid to copper sulfate solution will
form a precipitate, and it's probably better to go with the high-yield and straightforward synthesis from sodium phosphate. |
Ok, your experiment shows that copper phosphate is soluble, in which case adding sodium phosphate to a Cu<sup>2+</sup> solution will of
course not precipitate copper phosphate either.
So by NTODN's information, copper phosphate is soluble.
[Edited on 3-2-2015 by blogfast25] |
That isn't even close to what I was saying, and I'm frankly quite surprised that you interpreted what I said the way you did. If you'd listened when I
said I've already synthesized the compound, and I've told you that it's insoluble, and if you knew how acid and base reactions work, I don't see how
you could've arrived at the conclusion you just made. I dissolved the copper phosphate in sulfuric acid in order to prove that your earlier advice was
misplaced and incorrect.
| Quote: Originally posted by blogfast25 |
I've already recommended converting the copper basic carbonate to CuCl2 or CuSO4 first, to avoid problems of carbonate occlusion later on.
After that, basically dilute the Cu<sup>2+</sup> solution to about 1 M. Add the stoichiometric amount of 5.1 M H3PO4 to precipitate the
Cu<sub>3</sub>(PO<sub>4</sub><sub>2</sub>.
Filter, wash and dry.
In a nutshell...
[Edited on 2-2-2015 by blogfast25] |
Copper phosphate is INSOLUBLE in water, and forms as a gelatinous deep blue precipitate or a pale blue powder when dry.
Earlier in the thread, you claimed that rather than use my recommended synthesis, that Ramium should add phosphoric acid to copper(II) sulfate in
order to precipitate copper(II) phosphate. This would never happen in a million years because sulfuric acid is a stronger acid than phosphoric acid,
hence why adding sulfuric acid to copper(II) phosphate dissolves it and ordinary water does not. I have no idea how you gleaned that copper phosphate
was water-soluble based on the fact that sulfuric acid reacts with it.
Here's a bit more info on the compound, it's an article that zts16 and I wrote: http://sciencemadness.wikia.com/wiki/Copper(II)_phosphate
Yes, the reaction between copper(II) carbonate and excess phosphoric acid will produce insoluble copper(II) phosphate if the two are very well mixed
and every single square nanometer of copper(II) carbonate's area comes into contact with the acid. This will be very messy due to carbon dioxide
evolved and the viscosity of the acid. IT IS MUCH SIMPLER TO COMBINE SOLUTIONS OF COPPER SULFATE AND SODIUM PHOSPHATE, which WILL generate an
INSOLUBLE PRECIPITATE. So hopefully saying everything again in a clear way will remove any further confusion.
[Edited on 2-3-2015 by No Tears Only Dreams Now]
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blogfast25
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| Quote: Originally posted by No Tears Only Dreams Now | This would never happen in a million years because sulfuric acid is a stronger acid than phosphoric acid, hence why adding sulfuric acid to copper(II)
phosphate dissolves it and ordinary water does not. I have no idea how you gleaned that copper phosphate was water-soluble based on the fact that
sulfuric acid reacts with it.
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The fact that sulphuric acid is a stronger acid than H3PO4 isn't relevant here, copper sulphate doesn't contain any sulphuric acid.
If, e.g. you were to add H3PO4 to a solution of CaCl2, insoluble calcium phosphate would precipitate because the solubility product of calcium
phosphate would have been exceeded. The strength of HCl has nothing to do with it.
If copper phosphate is insoluble then 10 % H2SO4 would be far too weak to dissolve it.
If copper sulphate is truly insoluble then combining copper sulphate solution with trisodium phosphate solution would of course work, no contest
there.
That wikia link contains a glaring error BTW: CuCO<sub>3</sub> simply doesn't exist.
[Edited on 3-2-2015 by blogfast25]
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Amos
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| Quote: Originally posted by blogfast25 | | Quote: Originally posted by No Tears Only Dreams Now | This would never happen in a million years because sulfuric acid is a stronger acid than phosphoric acid, hence why adding sulfuric acid to copper(II)
phosphate dissolves it and ordinary water does not. I have no idea how you gleaned that copper phosphate was water-soluble based on the fact that
sulfuric acid reacts with it.
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The fact that sulphuric acid is a stronger acid than H3PO4 isn't relevant here, copper sulphate doesn't contain any sulphuric acid.
If, e.g, you were to add H3PO4 to a solution of CaCl2, insoluble calcium phosphate would precipitate because the solubility product of calcium
phosphate would have been exceeded. The strength of HCl has nothing to do with it.
If copper phosphate is insoluble then 10 % H2SO4 would be far too weak to dissolve it.
[Edited on 3-2-2015 by blogfast25] |
Okay, post your equation for the conversion of copper sulfate to copper phosphate by the addition of phosphoric acid so I can see what you think is
going on. What you appear to be describing is this:
3 CuSO4 + 2 H3PO4 = Cu3(PO4)2 + 3 H2SO4
And for the record, none of what I'm posting here is theory. I have personally conducted every reaction I've stated; I've intentionally synthesized
copper phosphate at least 3 times the same way I've repeatedly described. Its solubility in water is akin to that of copper hydroxide at best.
[Edited on 2-3-2015 by No Tears Only Dreams Now]
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blogfast25
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The first search result here (a *.pdf):
https://www.google.co.uk/?gws_rd=ssl#q=copper+phosphate+solu...
... gives the solubility products of calcium phosphate and copper phosphate resp. as: 2.07 x 10<sup>-33</sup> and 1.4 x
10<sup>-37</sup>. This confirms the insolubility of both with the copper phosphate being even more insoluble than the calcium phosphate.
Based on these I will now calculate whether H3PO4 is supposed to precipitate them or not.
[Edited on 4-2-2015 by blogfast25]
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Amos
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| Quote: Originally posted by blogfast25 | The first search here (a *.pdf):
https://www.google.co.uk/?gws_rd=ssl#q=copper+phosphate+solu...
... gives the solubility products of calcium phosphate and copper phosphate resp. as: 2.07 x 10<sup>-33</sup> and 14 x
10<sup>-37</sup>. This confirms the insolubility of both with the copper phosphate being even more insoluble than the calcium phosphate.
Based on these I will now calculate whether H3PO4 is supposed to precipitate them or not. |
Besides what you think will happen, the author of the thread already described adding their phosphoric acid to a solution of copper(II) chloride and
receiving no precipitate. When I get home today I will gladly combine solutions of copper(II) sulfate and phosphoric acid, and then do the same with
calcium chloride and phosphoric acid, and I'll take a video of both.
Oh, and if what you're saying about the strength of an acid not mattering is true, I should be able to produce sulfuric acid by adding aspirin to a
copper sulfate solution, because the copper acetylsalicylate will precipitate out.
[Edited on 2-3-2015 by No Tears Only Dreams Now]
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blogfast25
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| Quote: Originally posted by No Tears Only Dreams Now |
Oh, and if what you're saying about the strength of an acid not mattering is true, I should be able to produce sulfuric acid by adding aspirin to a
copper sulfate solution, because the copper acetylsalicylate will precipitate out. PO<sub>4/sub><sup>3-</sup>
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You are completely neglecting the solubility products in your truncated 'theory'. One of the weakest acids known, H<sub>2</sub>S,
precipitates CuS (also HgS) from any copper salt, sulphate included. Copper acetylsalicylate will precipitate out, IF it is insoluble
enough.
Simple calculation shows that for a 1 M H3PO4 solution the expected pH is about 1. Using the equilibrium equations for the deprotonation of H3PO4 it
can the be calculated that the PO<sub>4</sub><sup>3-</sup> concentration would be in the order of 10<sup>-24</sup>
M and that is too low to exceed the solubility product for either copper or calcium phosphate and neither would indeed precipitate.
A sodium phosphate solution would achieve that because the PO<sub>4</sub><sup>3-</sup> is much higher.
That has however nothing to do with the strength of the acid of the conjugated base of the copper or calcium salt and everything with the solubility
products of the phosphates and the extremely weak third deprotonation of H3PO4.
Let me now also calculate whether Cu3(PO4)2 is supposed to be soluble in 10 % H2SO4 or not.
[Edited on 3-2-2015 by blogfast25]
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Amos
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If I'm neglecting solubility products, then I'm only doing what you did you for the first 90% of this thread while repeatedly claiming that a
precipitate would form(it won't, as you now know). I'm only discussing a general trend on how NOT to produce insoluble transition metal salts; it's
generally going to be a better idea to produce a soluble salt of the acid and a soluble salt of the transition metal and combine the two. This whole
argument lifted off because you threw my tried and true method out of the conversation entirely and claimed the smarter way was to dump phosphoric
acid into a copper salt solution. A better time to have brought out the mathematics you're doing now would have been BEFORE you misinformed the author
of this thread who then proceeded to waste their reagents carrying out your unresearched methods.
[Edited on 2-3-2015 by No Tears Only Dreams Now]
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blogfast25
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10 % H2SO4 is very approx. 1 M H2SO4. The pH would be close to 0.
At that pH the PO<sub>4</sub><sup>3-</sup> concentration would be in the order of 10<sup>-22</sup> M, again this
value is not high enough to exceed the solubility product of Cu3(PO4)2 and the prediction is that 10 % H2SO4 would dissolve it.
The distribution of the phosphate as PO<sub>4</sub><sup>3-</sup>, HPO<sub>4</sub><sup>2-</sup>,
H<sub>2</sub>PO<sub>4</sub><sup>-</sup> and H<sub>3</sub>PO<sub>4</sub> species is another
matter.
[Edited on 3-2-2015 by blogfast25]
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blogfast25
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No, what I did was assume, wrongly, that the solubility product was low enough for copper phosphate to form with phosphoric acid.
That last burst was deeply childish, No Tears. 'Nerner nernnerner' type thing.
Your accusations are rather rich considering you based your arguments on a truncated theory of acid displacements.
You should perhaps also consider why oxalic acid precipitates calcium oxalate from any calcium salt, including calcium nitrate.
[Edited on 3-2-2015 by blogfast25]
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Amos
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| Quote: Originally posted by blogfast25 |
No, what I did was assume, wrongly, that the solubility product was low enough for copper phosphate to form with phosphoric acid.
That last burst was deeply childish, No Tears. 'Nerner nernnerner' type thing. |
I agree it was, but what I said wasn't wrong. As you were responding I was furiously editing the post to include more substance, but you probably
won't enjoy the rest of that much.
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blogfast25
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You're being puerile.
I gladly owe up to my mistake of judging the solubility of copper phosphate wrongly. I believed it was insoluble enough. Move on.
Do you owe up to yours?
[Edited on 3-2-2015 by blogfast25]
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Amos
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Yeah, I knew what happened in the case of this synthesis but I wasn't exactly sure of the reason, so the science of what I was discussing was just as
flawed as what I've accused you of. Hopefully both of us will walk away with something as a result of this.
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blogfast25
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Lets just try and get old Ramium back on track.
If he hasn't ditched the copper and phosphoric acid bearing solution and remembers the amounts used, then a simple neutralisation of the H3PO4 with
NaOH or ammonia would still yield the desired copper phosphate.
Alternatively he can neutralise the required amount of H3PO4 5.1 M and add it to a neutral solution of copper basic carbonate in
H2SO4 or HCl.
Considering the low value of the K<sub>a3</sub> of H3PO4, pH control is important here.
[Edited on 3-2-2015 by blogfast25]
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Ramium
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| Quote: Originally posted by No Tears Only Dreams Now | | Quote: Originally posted by blogfast25 | | Quote: Originally posted by No Tears Only Dreams Now |
I just took some of my copper phosphate(I have it on hand, having made it several times) and found that it dissolved completely and easily in dilute
sulfuric acid(about 10% concentration) to form a light blue solution. So no, I don't think that adding phosphoric acid to copper sulfate solution will
form a precipitate, and it's probably better to go with the high-yield and straightforward synthesis from sodium phosphate. |
Ok, your experiment shows that copper phosphate is soluble, in which case adding sodium phosphate to a Cu<sup>2+</sup> solution will of
course not precipitate copper phosphate either.
So by NTODN's information, copper phosphate is soluble.
[Edited on 3-2-2015 by blogfast25] |
That isn't even close to what I was saying, and I'm frankly quite surprised that you interpreted what I said the way you did. If you'd listened when I
said I've already synthesized the compound, and I've told you that it's insoluble, and if you knew how acid and base reactions work, I don't see how
you could've arrived at the conclusion you just made. I dissolved the copper phosphate in sulfuric acid in order to prove that your earlier advice was
misplaced and incorrect.
| Quote: Originally posted by blogfast25 |
I've already recommended converting the copper basic carbonate to CuCl2 or CuSO4 first, to avoid problems of carbonate occlusion later on.
After that, basically dilute the Cu<sup>2+</sup> solution to about 1 M. Add the stoichiometric amount of 5.1 M H3PO4 to precipitate the
Cu<sub>3</sub>(PO<sub>4</sub><sub>2</sub>.
Filter, wash and dry.
In a nutshell...
[Edited on 2-2-2015 by blogfast25] |
Copper phosphate is INSOLUBLE in water, and forms as a gelatinous deep blue precipitate or a pale blue powder when dry.
Earlier in the thread, you claimed that rather than use my recommended synthesis, that Ramium should add phosphoric acid to copper(II) sulfate in
order to precipitate copper(II) phosphate. This would never happen in a million years because sulfuric acid is a stronger acid than phosphoric acid,
hence why adding sulfuric acid to copper(II) phosphate dissolves it and ordinary water does not. I have no idea how you gleaned that copper phosphate
was water-soluble based on the fact that sulfuric acid reacts with it.
Here's a bit more info on the compound, it's an article that zts16 and I wrote: http://sciencemadness.wikia.com/wiki/Copper(II)_phosphate
Yes, the reaction between copper(II) carbonate and excess phosphoric acid will produce insoluble copper(II) phosphate if the two are very well mixed
and every single square nanometer of copper(II) carbonate's area comes into contact with the acid. This will be very messy due to carbon dioxide
evolved and the viscosity of the acid. IT IS MUCH SIMPLER TO COMBINE SOLUTIONS OF COPPER SULFATE AND SODIUM PHOSPHATE, which WILL generate an
INSOLUBLE PRECIPITATE. So hopefully saying everything again in a clear way will remove any further confusion.
[Edited on 2-3-2015 by No Tears Only Dreams Now] |
is it possible that i added to much HCL so when the copper
phosphate formed it was dissolved by the HCL forming a solution
[Edited on 3-2-2015 by Ramium]
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