Now that i have a basic knowledge of how to make solutions(thanks again for all you're help with that) i have decided to make up a few solutions not
for any percific purpose (although I do intend to work through some basic experiments/demonstrations mainly from Wollens site so any input from the
man himself would be appreciated) but mainly just to get some practical experience, i find it makes more scene when you actually physically do it!!
Also it would appear that theirs a lot more to making useful solutions than just mixing the correct amount of a compound to the correct amount of
distilled water(i recently learnt this the hard way)E.G. potassium permanganate is mixed very weak and potassium bichromate for some reason which i'm
sure will soon become apparent seems to made with sulphuric acid.
Anyway i intend to start with a list of solutions that i have already made(probably badly)and a list of solutions that i feel will be useful and a
list of chemicals that i have that i'm not sure can be made into solutions at least with water as the solvent.
I hope to pick up some general tips and a few do's/don'ts and i suspect a few 'that's just stupid s'
I would also like people to add solutions they use a lot to build up a sort of reference for beginners like myself.
Here's what i've made so far:-
copper sulphate 1mol/l 14%wt
potassium dichromate .4mol/l 11.1%wt
potassium permanganate .1mol/l 3.2%
potassium hydroxide 1mol/l 5.4%wt
sodium hydroxide 1mol/l 3.9%wt
ferrous sulphate 1mol/l I think i may have made a balls of this as i wasn't sure of the h2o content so i decided to dry it out to a anhydrous
state and make the solution from their,but i've ended up with a brown coloured liquid with some grey looking sediment opps DJF90 - 27-7-2009 at 15:03
itchyfruit - If your ferrous sulfate solution is brown then it means that the iron content has been oxidised, from pale green Fe (II) to red/brown Fe
(III). The best way to go about making this solution is to do so in 1M sulfuric acid - the acid prevents the oxidation, but still dont expect the
solution to stay green for long - a couple of days max. Mohr's salt may offer a decent alternative, and is a nice practical to perform. I'm sure I
posted the details here somewhere. It's ammonium iron sulfate, (NH4)2SO4*FeSO4. Not sure about water of hydration here though, you can find details
elsewhere (maybe included in the post I mentioned before). It seems to resist oxidation very nicely, my old teacher had a sample that was kept on the
windowledge for a couple of years, and despite being a little dusty, it was still remarkably green.entropy51 - 27-7-2009 at 15:49
Look at me! I dissolved some chemicals in water. I'm so proud of myself! itchyfruit - 27-7-2009 at 16:15
You as well, well done mate itchyfruit - 27-7-2009 at 16:29
Could it have anything to do with me putting it in the oven at 150oc for 30 mins it was certainly pale green before i baked it
You make an interesting point thou, their must be a lot of solutions that you have to make just before you use them.
hopefully people will point out any that i have in my forthcoming list!!!
I bet you can't wait entropy51 - 27-7-2009 at 16:46
Sorry, I couldn't resist.
Ferrous SO4 is easily oxidized.
Do some reading, for gosh sake. I'm all for learning by doing, but you gotta read, mate.itchyfruit - 27-7-2009 at 17:11
I know,but i just like to see how it works in practise it helps me remember, especially when i get it wrong entropy51 - 27-7-2009 at 17:15
With that winning attitude, one day you'll get it wrong and make a shitload of H2S or arsine and not remember anything ever after.
Chemistry is a learned profession; read some damn books.bfesser - 27-7-2009 at 17:38
Be sure to read the MSDS for all of those chemicals. Especially for the dichromate and permanganate. Both are strong oxidizers, and hexavalent
chromium is a nasty carcinogen--avoid aerosols. And don't dump them down the drain! Bottle them up safely, and bring them to a local hazchem
station.
[Edited on 7/28/09 by bfesser]itchyfruit - 27-7-2009 at 18:13
I do read books, maybe not enough but i do read, and when i do i just end up with more questions!!
I just like to try things out and i haven't just spent a couple of grand building my little old lab to sit in it and read books
Thanks for the concern but i do read the MSDS sometimes i print them off and keep them with anything really nasty.
H2S sounds fairly easy to make (especially by accident)hence another good reason for my list !!!triplepoint - 3-9-2012 at 08:30
i do read the MSDS sometimes i print them off and keep them with anything really nasty.
I think its worth a reminder - always print and organize ALL your MSDS sheets. Even if you think they are useless bureaucratic BS. If you ever have
a visit from government personnel due to a fire or a call from a nosy neighbor, etc., this will help you look safer and less out of control. Also,
label everything, keep your workspace (relatively) clean and store your materials in as secure and professional a manner as your finances permit.
Sorry to revive an ancient thread, but I am in the process of reading through the site and just reached it.triplepoint - 3-9-2012 at 08:30
i do read the MSDS sometimes i print them off and keep them with anything really nasty.
I think its worth a reminder - always print and organize ALL your MSDS sheets. Even if you think they are useless bureaucratic BS. If you ever have
a visit from government personnel due to a fire or a call from a nosy neighbor, etc., this will help you look safer and less out of control. Also,
label everything, keep your workspace (relatively) clean and store your materials in as secure and professional a manner as your finances permit.
Sorry to revive an ancient thread, but I am in the process of reading through the site and just reached it.smaerd - 3-9-2012 at 09:00
It would probably be pretty important to explain why these solutions are important and what they can be used for. Other then just listing chemicals
and percentages. Then again making a KOH or NaOH solution doesn't have any niche uses. So maybe this post is pretty vacuous.platedish29 - 3-9-2012 at 09:06
Important is to note that if you expect to keep the waste material for later disposal do never throw mixed solution of oxydisers like dichromate and
permanganate with organic material and/or other reduxing agents.AJKOER - 3-9-2012 at 14:56
Many salts (especially heavy metals) undergo hydrolysis, so placing them in solutions for 'storage' may not be wised. It is sometime recommended to
add an appropriate acid, or in the case of AgClO3, for example, Ag2O to delay decomposition. Research!
Temperature can also accelerate the process and increasing contact with the environment (through a solution which could also be slowly reacting with
the bottle also, or perhaps a lot of air in the vessel itself) may be detrimental to preservation. Interestingly, frequency of opening the container
and exposing it to air, can precipitate a chemical change (case: the tragic formation of 'fulminating silver' as ammonia is loss).
Also, definitely use O2 and CO2 free distilled water (boil before use). When removing the salt from the container, use clean equipment to avoid
contamination. Also, when preparing a salt, wash sufficiently to remove impurities.
Note, some salts (especially Silver) are photosensitive so a dark bottle may be required, again research.
[Edited on 3-9-2012 by AJKOER]Hexavalent - 4-9-2012 at 12:53
