Sciencemadness Discussion Board

The Short Questions Thread (4)

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Parakeet - 26-8-2023 at 03:56

Why does magnesium metal turn black in air?

I first believed that it's because the surface oxidizes. But, both MgO and MgCO3 are white, not black.
And I'm not aware of any black magnesium compounds.

Why is this?

clearly_not_atara - 26-8-2023 at 05:31

I think that small particles of unoxidized Mg are incorporated into the tarnish layer, darkening it. Not sure though. Manganese is a common alloying additive for magnesium, but it's used in extremely small amounts (<1%).

yobbo II - 15-9-2023 at 06:46



Would it be a sulphite you are looking at. Silver turnes black (ish).

Yob

yobbo II - 15-9-2023 at 06:47


In the book Introduction to magnetism and magnetic materials by David Jiles page 34 it gives a table
shown below. The figures of x and ur do not seem to make sense (according to the formula below the
table).
Am I missing something or is the table wrong?

Yob

sus.gif - 38kB

khlor - 15-9-2023 at 15:05

has anyone dissolved lead or tin in an alkaline aqueous solution like it can be done with zinc? NaOH preferably?

yobbo II - 15-9-2023 at 15:40


If you want a Sodium Plumbate (I believe it is called) you can dissolve Lead oxide (PbO) in NaOH.


Yob

[Edited on 15-9-2023 by yobbo II]

yobbo II - 21-9-2023 at 11:35


Maths leg up required (get out the spoons)

Can anyone tell me how to get from line 1 to line 2 in the pictures attached.
Thanks,
Yob

mag.gif - 104kBmag_2.gif - 117kB

yobbo II - 3-10-2023 at 16:52



This case is now closed :cool:

B = UoH + UoM

UoM = B - UoH

Divide both sides by H

Uo X = (B/H) - Uo [ X = M/H = susceptance = Ur -1 BTW]

Uo(Ur - 1) = (B/H) - Uo

UoUr - Uo = (B/H) - Uo

B = UoUrH

B = U H




and the second one

B = Uo(H + M)

B = Uo(Ni/L + M) H = Ni/L

B = UoUr(HI/L) FROM RESULT ABOVE

B = U Ni/L

Ni = BL/U

Cheers,
Yob

yobbo II - 16-10-2023 at 16:04


Hello,

Not too sure if this is appropriate here .. but

I am trying to sort a spread sheet on a certain columb.
The columb in questing contains a very large number, 15 digits.
I do not want to sort the sheet on the actual value of this number but rather on the value of the last three digits of the number.
In other words I want to sort the sheet using the last three digits of the columb containing the very large number.
Cannot figure it out. Using a fairly old version of excell.
If I could AND the number with 0000000000000111 (12 zeroes and three ones) I would strip away the digits I do not want (create a new columb and sort on the new columb but I am unable to do this AND.

Cheers,
Yob

B(a)P - 16-10-2023 at 16:35

Quote: Originally posted by yobbo II  

Hello,

Not too sure if this is appropriate here .. but

I am trying to sort a spread sheet on a certain columb.
The columb in questing contains a very large number, 15 digits.
I do not want to sort the sheet on the actual value of this number but rather on the value of the last three digits of the number.
In other words I want to sort the sheet using the last three digits of the columb containing the very large number.
Cannot figure it out. Using a fairly old version of excell.
If I could AND the number with 0000000000000111 (12 zeroes and three ones) I would strip away the digits I do not want (create a new columb and sort on the new columb but I am unable to do this AND.

Cheers,
Yob


Insert a new column.
In the first row of your new column include the formula
=RIGHT(A1,3)
assuming your large number is in column A starting in row one, so the first number you want to sort is in cell A1.
Drag the formula to the bottom of the sheet.
Select all of the columns that you want to sort and sort by your new column.
Is this what you were trying to achieve?

solo - 16-10-2023 at 20:04

....i have 2-tert butyl-1-phenyl ethanol and i want to nitrate the ring, i was thinking of using anhydrous ethanol as my solvent since the material is a powder, or can someone suggest another solvent that i can use.....solo

[Edited on 18-10-2023 by solo]

yobbo II - 17-10-2023 at 13:21

Thanks alot B(a)P,

That was exactly what I needed.
There is still a small problem but only a small one. I need to do the sorting very seldom.

It may be just a software glitch from using old Works.

When I paste in my info. the column (col A) with the large number gets pasted in in scientific notation (the number in notepad before pasting is just a simple 15 digit number).
I convert the column (A) to text and the number stayes as scientific notation.
The only way to 'convert' back to a 15 digit number is to double click on the number.
Sounds a bit weird.
Any suggestions?
The picture explaines things a bit better.

Thanks alot,
Yob

@solo appologies for talking over you!

exel.gif - 137kB

[Edited on 17-10-2023 by yobbo II]

B(a)P - 17-10-2023 at 14:03

Quote: Originally posted by yobbo II  
Thanks alot B(a)P,


When I paste in my info. the column (col A) with the large number gets pasted in in scientific notation (the number in notepad before pasting is just a simple 15 digit number).
I convert the column (A) to text and the number stayes as scientific notation.
The only way to 'convert' back to a 15 digit number is to double click on the number.
Sounds a bit weird.
Any suggestions?

[Edited on 17-10-2023 by yobbo II]


Make the column wide enough to accomodate 15 digits. Select the column, then format as a number and it should go back to non-scientific notation. The default format for numbers is two decimal places so you may need to fix that as well by pressing the decrease decimal button a couple of times.

Dr.Bob - 18-10-2023 at 09:03

Or just use the MOD function and do X MOD 1000, which will return only the remainder of a division by 1000. For the text to work, you would need to use right(text(X,0),3) or something like that to convert the number to text, then use the right 3 digits. You can also use the format cell feature to set the cells to "text", where numbers are not converted to a real value, but saved as the text characters, and then right(x,3) will work.

yobbo II - 18-10-2023 at 14:46



I cannot get the =MOD(Ax, 1xxx) to work as the sheet gives an error. This must be a bug?
Both B2 and B3 are formatted as numbers. Setting greater number of decimal places does not help (It should not matter anyways)
See the picture

I got the sheet to work with the following:

I used the =string(Ax,0) (same as =text(xxx) I guess) to convert to general format this gets rid of the scientific notation
followed by =right(Ax, 4) to give me the four digits to sort on.

Thanks for you time

mod_error.gif - 39kB

Dr.Bob - 18-10-2023 at 16:54

I just checked and it seemed to work fine for me:

=MOD(2387373278378,1000) provides 378 for me.

but if the text way worked, that is fine as well.

Fluorite - 24-10-2023 at 01:27

Can copper sulfide be made by electrolysis sodium sulfide solution using copper anode? will the rest of the solution be just sodium hydroxide?

DraconicAcid - 24-10-2023 at 11:13

I wouldn't expect so- I'd guess that the anode would become coated with non-conductive copper(II) sulphide. If you had any other copper salt in solution or suspension, it should react with the sodium sulphide solution to give CuS, which is ridiculously insoluble.

solo - 4-11-2023 at 07:52

...help finding the correct name for compound ...i tried 2-ethyltert butylamine-1-phenylbenzoate ...but no results....its a steroid precursor .....solo

unknown namen of compound.jpg - 68kB

[Edited on 4-11-2023 by solo]

Bedlasky - 11-11-2023 at 08:00

2-(tert-butylamino)-1-phenylethyl acetate

solo - 11-11-2023 at 15:34

...thanks Bedlasky any suggestions on the type of solvent to use in a p-nitration of this 2-(tert-butylamino)-1-phenylethyl acetate or its 2-(tert-butylamino)-1-phenylethanol alcohol.....solo

note: I have searched around and found two candidatea, methanol and DCM

[Edited on 12-11-2023 by solo]

FableP - 11-11-2023 at 18:51

Likely a very noob question here, I have seen a synthesis for hydroxylamine HCL where nitromethane and HCl are refluxed for many hours, similarly I've seen the same for hydroxylamine sulphate with nitromethane and sulphuric acid, however when looking on how to synthesise hydroxylamine nitrate, most synthesis point towards reacting barium nitrate with hydroxylamine sulphate.
Will the following proceed to hydroxylamine nitrate: CH3NO2 + HNO3 + H2O → [NH3OH]NO3 + HCOOH
or is some other reaction pathway followed for a different product?

Bedlasky - 12-11-2023 at 09:46

I don't think that this will work. Hydroxylamine is strong reducing agent and refluxing it with HNO3 will probably destroy it. It could be actually pretty dangerous, because hydroxylamine reacts with some oxidizing agents pretty violently even in aqueous solution:

https://woelen.homescience.net/science/chem/exps/hydroxylami...

I hope you know that hydroxylammonium nitrate is explosive.

FableP - 12-11-2023 at 17:27

I'm planning a HiPEP project. It looks like BaNO3 might be the way to go.

j_sum1 - 12-11-2023 at 20:37

Quote: Originally posted by FableP  
I'm planning a HiPEP project. It looks like BaNO3 might be the way to go.


HiPEP??
I have no idea if you are taking about a herbal remedy claimed to cure intestinal bloating or High Power Electric Propulsion.

Please make your posts clear.
In the meantime, the formula for barium nitrate is Ba(NO3)2.

FableP - 12-11-2023 at 21:53

High Powered Electric Propulsion - Electric solid propellant

http://eplab.ae.illinois.edu/Publications/IEPC-2019-421.pdf
and
https://scholarsmine.mst.edu/cgi/viewcontent.cgi?article=383...

Table 1: Chemical composition of the High Performance Electric Propellant (HIPEP).

Hydroxyl Ammonium Nitrate (HAN) (NH3OH)+ NO3 - 75%
Polyvinyl Alcohol (PVA) CH2CH(OH) - 20%
Ammonium Nitrate (AN) NH4NO3 - 5%

Thanks for pointing out the correct formula for barium nitrate.

j_sum1 - 12-11-2023 at 22:28

Mmm.
I am always a bit concerned when someone who can't balance an ionic formula starts playing around with significant quantities of energetics.

Be aware also that barium compounds are toxic to humans and the environment. Make sure you manage the risks and have a dispisal plan.

Why does the nitrate ion exist?

Sulaiman - 13-11-2023 at 06:11

The obvious answer is, because it does.
But the charge distributions make no sense to me
(I get the idea of resonance but don't understand why the ion is stable)
(is it the surrounding water molecules that stabilise it?)
anyone have an answer that I might understand?

clearly_not_atara - 13-11-2023 at 08:43

Symmetry!

Nitrate has three resonances:

(ON+(O-)O- + O-N+(O)O- + O-N+(O-)O) / sqrt(3)

According to the uncertainty principle, the more space an electron orbital occupies, the smaller the associated kinetic energy it requires to be admissible. It's got nothing to do with water molecules or other coordinations; the stability of alkali metal nitrates increases with ion size:

CsNO3 > RbNO3 > KNO3 > NaNO3 > LiNO3

with CsNO3 stable to around 700 C and LiNO3 decomposing below 400 C. Of course, this is precisely opposite to the coordination strength of the ions. And indeed the hydrogen compound is already slowly decomposing at room temperature.

Iron (II) sulfate

Chemgineer - 6-12-2023 at 14:45

I bought some sulfate of iron fertilizer from a garden centre wit the aim of purifying it to some FeSO4 crystals. When dissolved in water there was allot of light brown material which passed through my filter so I left it to settle for 24 hours.

I managed to pour off a nice green coloured solution and discarded the brown sludge.

I then tried to boil some of this down with the idea to drop out some crystals of iron sulfate.

What I notice is that as it is heated and concentrated I get a brown residue on the beaker and my solution become more cloudy. Is Iron II Sulfate difficult to purify? I see it might produce brown oxides in the presence of water.

Would I be better pouring it all into a big bucket and simply allowing it to evaporate over a few weeks to grow crystals?

DraconicAcid - 6-12-2023 at 14:52

The brown crud is from oxidation of iron(II) to iron(III), which happily precipitates as various forms of rust. You might try adding excess sulphuric acid to prevent this.

Chemgineer - 6-12-2023 at 15:06

Quote: Originally posted by DraconicAcid  
The brown crud is from oxidation of iron(II) to iron(III), which happily precipitates as various forms of rust. You might try adding excess sulphuric acid to prevent this.


You are of course right, I just added some sulphuric acid to my hot boiling solution and it has gone from brown to green! I am learning!

DraconicAcid - 6-12-2023 at 17:00

PS- if you're looking to get crystals, rather than just purifying the compound, I believe double salts such as (NH4)2Fe(SO4)2 give better crystals than the plain sulphate.

Thorium nitrate

Sir_Gawain - 14-12-2023 at 07:50

Will ThO2 dissolve in nitric acid?

[Edited on 12-14-2023 by Sir_Gawain]

woelen - 15-12-2023 at 00:12

I don't think so, or only with great difficulty. ThO2, like many other oxides, is quite inert if it is calcined.
When it is freshly prepared from aqueous solution, then you have some hydrous form ThO2.xH2O, which easily dissolves in acids. These hydrous oxides (or mixed oxides/hydroxides??) are quite different from the anhydrous calcined oxides.

Sir_Gawain - 26-12-2023 at 15:51

Could molecular sieves be used to dry nitric or sulfuric acids? I can’t think of a reason why it wouldn’t work for nitric, but I’m probably missing something.

[Edited on 12-26-2023 by Sir_Gawain]

Sir_Gawain - 26-12-2023 at 16:02

Never mind. I just tried it with some azeotropic nitric acid and it completely destroyed the sieves.
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