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 on: Today at 03:54:00 AM 
Started by rolnor - Last post by rolnor
Is hydroiodic acid more powerfull vs hydrobromic acid for ether cleavage? I think it should be, itś a stronger acid and the iodo ion is a stronger nucleophile?

 on: Today at 03:27:37 AM 
Started by gapedbuh - Last post by gapedbuh

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 on: Today at 03:24:29 AM 
Started by oilypiggy - Last post by Mitch
The diagram is about nuclei separation, it has little to do with electron separation. Once electrons are close enough to overlap and form bonds they become indistinguishable, and discussing electron distance from each other becomes a bit meaningless.

 on: Today at 01:28:25 AM 
Started by DeltaSubz - Last post by Borek
I just skimmed over your numbers and nothing sticks out as obviously incorrect, but there is one thing that I would do differently:

[H3O+] + (0.36 M) = [H2PO4-] + 2[HPO42-] +3[PO43-] + [OH-]

Instead of writing 0.036 M I would first list all ions with coefficients. Makes it easier to check what you are doing.

 on: Yesterday at 11:56:05 PM 
Started by Docather - Last post by P
Any advice would be great!

Did you get anywhere with this? Why the need to distinguish?

 on: Yesterday at 11:24:25 PM 
Started by DeltaSubz - Last post by DeltaSubz
Hey all, first post here  :D
Anyways, it seems there will be some mass/charge balance questions on my upcoming quant midterm and want to make sure i get this right. Im pretty sure i got the hang of mass balance, but not so much charge balance. An example problem is as follows, and my answers are in red...

A solution is prepared using 0.01 mol of Na2HPO4, 0.02 mol of Ca(H2PO4)2, and 0.02 mol of Mg3(PO4)2. In a total volume of  0.50 L.

a.   Write all mass balance equations for this solution
[Na+] = 0.04 M
[Ca2+] = 0.04 M
[Mg2+] = (3*0.02)/0.5 = 0.12 M
[H3PO4] + [H2PO4-] + [HPO42-] + [PO43-] = ( 0.01 + (2*0.02) + (2*0.02))/0.5 = 0.18 M

b.   Write the charge balance equation for this solution. Where appropriate, replace general concentration terms with actual concentrations.
[H3O+] + (0.36 M) = [H2PO4-] + 2[HPO42-] +3[PO43-] + [OH-]

Can anyone knowledgeable in this area verify whether this is right/wrong?

 on: Yesterday at 10:33:52 PM 
Started by Wanderer0 - Last post by AWK
Neither in crystals nor in solutions of ionic compounds have covalent bonds between ions. The total formula informs us only about the composition of the stoichiometric unit of the compound.

After graduation, the chemist has intellectual tools to imagine the structure of a not very complicated chemical compound from its total formula (not always correctly, but he knows where to check it), e.g. copper sulfate pentahydrate in the crystal has a structure [Cu(H2O)4]SO4·H2O, and in the solution there are ions [Cu(H2O)6]2+ next to hydrated sulfate ions with undefined stoichiometry of water molecules (and therefore the water is omitted in ions, or it is included in the form of SO42-(aq) and then when balancing chemical reactions we neglect this (aq).

At pH 9, the solution also contains 10,000 times more OH- ions than the H3O+ ions. For both salts, the concentration of hydroxide ions is sufficient to immediately produce Cu(OH)2 (anhydrous) and Fe(OH)2 (hydrated with undefined stoichiometry)

You can find the rest in good textbooks.

 on: Yesterday at 10:18:26 PM 
Started by Wanderer0 - Last post by Borek
Will Fe2+ ions continue binding to SO42- until all are oxidased?

Ions in the solution, after dissociation, are not bound to any specific ion. The only thing that matters is that the solution is electrically neutral, what ions are present doesn't matter.

Ions can react and interact, making complexes or precipitates, but that's not the case of Fe2+ and SO42- (or, rather - complexing properties of SO42- are way too low to matter).

 on: Yesterday at 10:05:10 PM 
Started by Mitch - Last post by Borek
Nothing here, but my connection is rather slow, so chances are what I see is not limited by the software.

OTOH footer contains information about how fast the page was created - it is below 0.2 sec now ("Page created in 0.135 seconds with 29 queries."), I believe it was below 0.2 s before as well. From what I remember for human interaction everything below 0.25 s counts as "instant".

 on: Yesterday at 09:00:11 PM 
Started by Ondex - Last post by Ondex
Guys i think i did it.
I made some changes in the process of HEDP neutralisation and mixing of all ingredients, have already gone 2 days and no any cristals!!
I will try to oscillate the storage temperature to boost the crystallization processes, if it can still take place.
After 10 days I will be sure of the experiment.
Have a nice day!

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