January 24, 2021, 06:32:23 AM
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Organic Chemistry Forum / Re: hydrolysis of sucrose
« Last post by arpaco on Today at 06:03:09 AM »
Thanks for sharing




https://www.arpaco.ir

2
I dont' understand very well when a distortion (for example z axis elogantion/compression) can occour in an octahedral complex


-I've read that can occour when the six ligand are different...for example [M(Cl)4O2+/- n ...the oxygen ligands can cause a compression on the z-axis

- In another example I've seen a complex with  the same 6 ligands  [M(NH3)6] that can follow an octahedral distartion....but usually when is a d8


So can a distortion occour in both cases??
THANKS :)
3
Organic Chemistry Forum / Re: Halogenation of a carboxylic acid using SO2Cl2
« Last post by AWK on Today at 04:31:45 AM »
It all started with the question (which is in the title of the thread) whether SO2Cl2 can be used to synthesize acid chlorides. Meter showed a reaction that also includes DMF (he claims the reaction is from Wikipedia).
You started a discussion about the advisability of using DMF, and then the discussion went sidetrack.
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I dont understand how this is relevant for the question from Meter?
5
Analytical Chemistry Forum / Re: EDTA Titration
« Last post by Borek on Today at 03:30:27 AM »
Please read the forum rules.

What have you tried so far?

Titration is a simple stoichiometry combined with n=CV.
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Analytical Chemistry Forum / Re: Concentration
« Last post by AWK on Today at 03:20:57 AM »
For solids and liquids "w/w" is a default. Solutions of some biochemical (biomedical) reagents may be given in "w/v". Solutions of ethanol only may be given in "v/v" or proofs (but should be stated).
7
Analytical Chemistry Forum / Concentration
« Last post by Antreas on Today at 03:03:09 AM »
What is the default unit of concentration of commercial reagents when only "%" is stated and no "w/w", "w/v" or "v/v"?

H2SO4 98% (w/w or w/v?)
H2O2 30% (w/w or w/v?)

Thanks!
8
Analytical Chemistry Forum / EDTA Titration
« Last post by beefnachos12 on Yesterday at 09:00:12 PM »
Hi can someone teach me how to complete a table and solve for the following: molarity of Ca, Moles Ca, Milligrams Ca, Titer Ca (mg Ca/mL EDTA)? I am only given molarity of EDTA, final burette reading (mL).

Thank you!!
9
I think "volatility" is one of those words that expresses a general concept (liability to evaporate) but is not a precisely defined technical term. For example for an ideal mixture of A and B, the partial pressure of A vapour is xAA, where xA is the mole fraction of A in the liquid and P°A is the vapour pressure of pure A. The total vapour pressure of the mixture is given by
P = xAA + xBB
Now I think that saying the volatility of A is twice that of B is ambiguous, because "volatility" is not precisely defined. It could mean
A = 2P°B
or it could mean
xAA = 2xBB
The latter corresponds to your option 2; option 1 is ambiguous - is it referring to vapour pressures of pure A and B, or of A and B in the mixture?
I am getting a bit confused about this, well I'm sure that if we have the partial pressure of a component doubled (we  can also refer to partial pressure by saying vapour pressure of the component in the mixture, because we're talking about a liquid mixture), then we have the double of the particles of that component as the pressure only depends on the number of particles when the solution is ideal. In conclusion, so far I only found out this about volatility:

"Volatility itself has no defined numerical value, but it is often described using vapor pressures or boiling points (for liquids)",

while in my notes there's written "if P°A = p°B, then A and B have the same volatility". Considering that the right answer turned out to be the first option, I guess my teacher had the pure component vapour pressure as a definition of volatility.

Anyway, maybe I can't understand what the vapour pressure of the pure component is, I'd say it's the pressure the component would exert if that liquid was alone in the same container, but this way it looks quite the same as the definition of partial pressure.. Where is the mistake? Thanks for your time.
10
I think "volatility" is one of those words that expresses a general concept (liability to evaporate) but is not a precisely defined technical term. For example for an ideal mixture of A and B, the partial pressure of A vapour is xAA, where xA is the mole fraction of A in the liquid and P°A is the vapour pressure of pure A. The total vapour pressure of the mixture is given by
P = xAA + xBB
Now I think that saying the volatility of A is twice that of B is ambiguous, because "volatility" is not precisely defined. It could mean
A = 2P°B
or it could mean
xAA = 2xBB
The latter corresponds to your option 2; option 1 is ambiguous - is it referring to vapour pressures of pure A and B, or of A and B in the mixture?
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