Search found 1542 matches

by ChenBeier
Wed Feb 14, 2024 3:08 pm
Forum: Chemistry forum
Topic: Titration of mixture of KOH and K2CO3
Replies: 11
Views: 1249

Re: Titration of mixture of KOH and K2CO3

You cannot determine different Isotops of one element by titration. If you check for potassium then you will get all Isotopes together. The Isotopes are different by the amount of neutrons in the atom, this is not possible to figure out by chemical analysis. The chemical behaviour is driven by the a...
by ChenBeier
Tue Feb 13, 2024 4:08 am
Forum: Chemistry forum
Topic: Titration of mixture of KOH and K2CO3
Replies: 11
Views: 1249

Re: Titration of mixture of KOH and K2CO3

In this case convert all to KCl. pH 7.

Probably the determination of molarity of HCl is also wrong. If it was only the half instead 0.0098 M only 0.0049 M then it would more or less fit.
by ChenBeier
Tue Feb 13, 2024 3:46 am
Forum: Chemistry forum
Topic: Titration of mixture of KOH and K2CO3
Replies: 11
Views: 1249

Re: Titration of mixture of KOH and K2CO3

The solution p Value is sum of KOH and 1/2 K2CO3 or KHCO3 ( ml HCl consumed Phenolphthalein) m value is sum of KOH and K2CO3 ( ml HCl consumed Methylorange) n (KOH) = 2 p - m = 2*(KOH + 1/2 K2CO3) - (KOH + K2CO3) = KOH n ( K2CO3) = 2*(m-p) = 2*(KOH + K2CO3 - (KOH + 1/2 K2CO3)) = K2CO3 n KOH = 2 * 26...
by ChenBeier
Sun Feb 11, 2024 11:24 pm
Forum: Chemistry forum
Topic: Titration of mixture of KOH and K2CO3
Replies: 11
Views: 1249

Re: Titration of mixture of KOH and K2CO3

Values for KOH and K2CO3 have to be exchangend.
See here an example with sodiumhydroxide and Carbonate

https://www.linkedin.com/pulse/analytic ... oda-kartal
by ChenBeier
Sun Feb 11, 2024 3:56 am
Forum: Chemistry forum
Topic: Chloroauric acid
Replies: 6
Views: 591

Re: Chloroauric acid

You need about 355 ml solvent for the 0.7 g.

But read how to make it

What is aqua Regina it is 3 part HCl and one part HNO3 .

https://en.m.wikipedia.org/wiki/Chloroauric_acid
You have to do boiling until all HNO3 is evaporated as NO2, later dissolve the product again in conc. HCl to get 355 ml
by ChenBeier
Sun Feb 11, 2024 3:40 am
Forum: Chemistry forum
Topic: Chloroauric acid
Replies: 6
Views: 591

Re: Chloroauric acid

I thing to figure out what is aqua Regina and the calculati8n you have to do by yourself.

Calculate the moles of Gold you have then covert this to the volume of the acid to get 0,01 M
by ChenBeier
Sun Feb 11, 2024 2:52 am
Forum: Chemistry forum
Topic: Chloroauric acid
Replies: 6
Views: 591

Re: Chloroauric acid

Dissolve in aqua Regina.
by ChenBeier
Sat Feb 10, 2024 1:21 pm
Forum: Chemistry forum
Topic: Titration of mixture of KOH and K2CO3
Replies: 11
Views: 1249

Re: Titration of mixture of KOH and K2CO3

Yes something doesn't fit.
The titration values are wrong or the method to get molarity of HCl.
by ChenBeier
Sat Feb 10, 2024 8:35 am
Forum: Chemistry forum
Topic: Titration of mixture of KOH and K2CO3
Replies: 11
Views: 1249

Re: Titration of mixture of KOH and K2CO3

It was asked for potassium not for potassium carbonate or hydroxide.
The moles for K2CO3 are wrong

K2CO3 + 2 HCl => 2 KCl + H2O + CO2

For 1 K2CO3 2 HCl needed or 1 HCl correspond to 1/2 K2CO3

n (K2CO3) =0,0261 *0,09817/2 = 0,001281 mol
by ChenBeier
Fri Feb 09, 2024 1:52 pm
Forum: Chemistry forum
Topic: Has anyone tried chloroform?
Replies: 1
Views: 265

Re: Has anyone tried chloroform?

Sorry we dont discuss this kind of things.
by ChenBeier
Fri Feb 09, 2024 7:07 am
Forum: Chemistry forum
Topic: Titration of mixture of KOH and K2CO3
Replies: 11
Views: 1249

Re: Titration of mixture of KOH and K2CO3

First get concentration of HCl

Develop the redoxreaction iodate iodine and the consumed H+.

IO3- + 5 I- + 6 HCl => 3 I2 + 3 H2O + 6 Cl-


With the two first titration you get K2CO3 pH 8.2 and the mixture with KOH pH 4.5 , the difference is KOH

From that calculate mass of K.
by ChenBeier
Mon Feb 05, 2024 11:56 am
Forum: Chemistry forum
Topic: Exercise on pH
Replies: 1
Views: 486

Re: Exercise on pH

Where did you get the ka value from? The value is wrong. Potassium nitrate is a salt made by nitric acid and potassium hydroxide. Both are strong chemicals, acid and base. Also pH should be near neutral. Ka of HNO3 = 20,89, pKa =-1,32 Normaly pH = 14 - 1/2 * (pkB - lg [c anion]) If the value is righ...
by ChenBeier
Fri Feb 02, 2024 3:43 pm
Forum: Chemistry forum
Topic: Electrochemistry
Replies: 3
Views: 1015

Re: Electrochemistry

You are right the concentration is less as 2 M
But its 2 mol/l - 8 *10^(-9) mol/l = 1,999999992 mol/l ~ 2 mol/l
So its near the same.
by ChenBeier
Fri Feb 02, 2024 12:39 pm
Forum: Chemistry forum
Topic: Electrochemistry
Replies: 3
Views: 1015

Re: Electrochemistry

Why do you think the concentration of SO4 2- is wrong. You have 2 M H2SO4 so the value is right.

E =E0 + 0,059V/ z * log c Pb 2+

c Pb 2+ = ksp(PbSO4) / c SO4 2-

cPb 2+ = 1,6 *10^-8 (mol/l)^2 / 2 mol/l = 8 *10^(-9) mol/l

E = -0,126 V+ 0,059/2 * log (8*10^(-9))
E = -0,126V -0,238 V
E = -0,36 V
by ChenBeier
Tue Jan 30, 2024 11:25 pm
Forum: Chemistry forum
Topic: Stoichiometry problem
Replies: 5
Views: 1675

Re: Stoichiometry problem

Why not give yours first?