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91
Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by kailee33 on December 02, 2024, 04:07:34 AM »
So Stoichiometry calculation for 10g of KAuCl4 would require 8.99g of HAuCl4 + 1.97g of KCL so a ratio of 21.9% KCL.

To give minimal excess this could be 30%??
92
Undergraduate General Chemistry Forum / Re: acid and bases
« Last post by Hunter2 on December 01, 2024, 07:55:22 PM »
The key is Hendersson Hasselbalch equation.
Check this.
93
Undergraduate General Chemistry Forum / Re: acid and bases
« Last post by Borek on December 01, 2024, 04:50:44 PM »
HC2H3O2

It is not clear what this intended to be. Acetic acid probably, but written in a way designed to be confusing.

Quote
a. pH 5 pKa
 b. pH 5 4.00
 c. pH 5 5.00

These numbers don't make much sense, please copy them correctly and we will start from there.

Quote
I started by finding the value of the ph for the

For the what?

94
Undergraduate General Chemistry Forum / acid and bases
« Last post by aaaaaa on December 01, 2024, 04:38:32 PM »
 What quantity (moles) of NaOH must be added to 1.0 L of 
2.0 M HC2H3O2 to produce a solution buffered at each pH?
 a. pH = pKa
 b. pH = 4.00
 c. pH = 5.00

I don't understand how to solve this. I started by finding the value of the ph for the then finding the pOH and then finding the concentration of the pOH but this answer seem to be wrong. I check the manual answers and my answer doesn't match. I think I'm supposed  to assume that the concentration for the acid and the conjugate base is the same and that they add up to be 2M as suggested in the problem therefore the conjugate base would be 1, since there's a 1:1 molar ratio OH would have the same concentration and the same amount of moles. I just don't understand why the first procedure that I used doesn't work and I also don't understand why the acid and the conjugate base should be equal to 2 since this is the concentration given for only the acid ??

Thank you
95
Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by kailee33 on December 01, 2024, 04:06:41 PM »
I  think for this purpose you don't need so pure compound. The removal of excess KCl is in my opinion not necessary.

Agreed, I would just like to minimise, hence why I was initially looking for approximate weights to use in the reaction, to keep excess potassium quite low
96
Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by kailee33 on December 01, 2024, 11:47:12 AM »
There is two routes I can take

The classic route in making a gold sulpho-resinate (Gold Salt + Sulphured resin)

Or the more modern route gold aryl mercaptide (Gold Salt + ethyl acetate + dimethylbenzenethiols + Polymer)

But I would prefer to work with more natural products
97
Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by Hunter2 on December 01, 2024, 07:32:40 AM »
I  think for this purpose you don't need so pure compound. The removal of excess KCl is in my opinion not necessary.
98
Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by kailee33 on December 01, 2024, 07:12:03 AM »
Thank you very much for the help Hunter, I will read up on fractional crystallisation.

I use gold chloride on pottery. This is mixed with an organic binder & flux. But I find the shelf life is short, the gold seems to revert back to metallic Au after a couple of weeks. So I am looking at a more stable salt of gold for longer storage.
99
Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by Hunter2 on December 01, 2024, 05:41:33 AM »
There is no AuCl4. You have AuCl3 or better Au2Cl6. The other one is HAuCl4.This is existing as Trihydrate. HAuCl4 * 3 H2O. If you dry it decompose.
Drying and separation of two chemical is a different thing.
Check the solubilities of KCl and KAuCl4 and do fractional crystallisation in water.
PS For what you need the KAuCl4 by the way.
100
Inorganic Chemistry Forum / Re: Synthesis of K(AuCl4) Potassium gold(III) chloride
« Last post by kailee33 on December 01, 2024, 04:46:38 AM »
Even if I dry it? I have successfully dried AuCl4 to powder it using a vacuum chamber and low heat?
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