I was thinking, a possible addition to the forum would be a subforum for people to ask before hand, "I'm thinking of doing this, or using this, is any
of this going to involve something toxic, and how should I deal with it?"
Combined with the opportunity for someone else to say, "Do it this way to save money, make it easier or make it less toxic".
That seems close to the beginners forum, but this would be specifically for asking in preparation to running something, as opposed to afterwards,
theoretical questions or them being mixed in with things about hotplates and fridge pumps.
Directly related to the health and safety of doing something first hand, and ease, like possible compatibility problems.
The process would simply be to state the rough reaction and/or reagents in the title and then a very simple description of what was going to be done.
e.g.
------------------------------------------------
Title: Producing ... salt with ...
Boiling A in B for 30 minutes, adding C dropwise, using plastic burette and beaker
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Very easy for someone else to say... "The burette's going to melt" or "That's going to fume off a carcinogen".
Anyone thinking such a person should already know themselves or use the MSDS is a member of the noobine collective. MSDS don't deal with interactions,
and DuPont will tell you it's your problem if something goes wrong with one of their product due to an interaction or compatibility issue. It's an
idiotic opinion to have on the moral grounds as well, that people should be embarrassed about asking for help avoiding harm as they try to learn;
particularly if you go on about safety gear but not why it's needed. The only solution to it is input from others saying "I've done that, don't repeat
it" or "Works fine".
[Edited on 10-10-2010 by peach]DDTea - 10-10-2010 at 03:50
So basically, what you're proposing is a pre-experiment/protocol review section? I think it's a good idea and this forum could certainly use that.
Really, having a second set of eyes to look over your ideas is a good thing. I don't think the focus should be only on risk reduction,
although that should definitely be a big part of it (it's easy to forget things like this). MSDS's don't tell everything and they're tailored more
toward people who regularly use the chemical described by the MSDS.
Also, it could encourage collaboration, which I'm also in favor of.
Quote:
It's an idiotic opinion to have on the moral grounds as well, that people should be embarrassed about asking for help avoiding harm as they try to
learn; particularly if you go on about safety gear but not why it's needed.
...couldn't agree more. I'm of the opinion that you shouldn't even need to wear heavy rubber gloves or a gas mask if you're doing things properly.
PPE is for when risk cannot be mitigated with engineering controls. Using a respirator as a primary means of protection is pretty reckless. psychokinetic - 10-10-2010 at 16:59
Good idea, separate the theory beginnings and the practical beginnings.Gearhead_Shem_Tov - 10-10-2010 at 17:51
This is a great idea. Perhaps it should have a sticky with it to give a suggested streamlined format for the subject line, something that tries to
get the essential information in brief -- the two or three chemicals/phases you're working with, the basic process (heating, cooling, crystallising,
separating, distilling, etc.), and the pressure/temp regime contemplated, if not STP.
This would be far better than "Help with Na" and such...
-B
[Edited on 11-10-2010 by Gearhead_Shem_Tov]woelen - 10-10-2010 at 23:29
Wouldn't it even be better to have a special section in the sciencemadness forum devoted to this? Each experiment then can have its own thread,
started with a post telling what action is intended.
There must, however, be quite some discipline if one really wants to make this succesful. The person, who posts the experimental procedure to be
reviewed must put some effort in it to make it really clear, must tell which steps he thinks he wants to take, etc. and must himself already provide
some questions. He also must provide a completely worked out experiment.
Just to illustrate what I mean, I give an example on how I would like to see something like this. In the example I want to make bromine from sodium
bromide by means of electrolysis and I want to do this by electrolyzing a solution of NaBr and after some time add acid to it to have any hypobromite
formed in the reaction converted to bromine again.
I want to make bromine from sodium bromide. I dissolve some sodium bromide in water and put some electrodes in it for electrolysis. After some time,
the bromide is converted to bromine and also hypobromite and bromate is formed. The next step is that Im add some acid to convert the mix of bromide,
hypobromite and bromate to bromine.
I want to make bromine from sodium bromide. In order to do so, I dissolve 1 mol of NaBr in 200 ml of water. And put this in an electrolysis cell. The
cell is constructed from a graphite anode (12 cm length, 8 mm diameter) and a stainless steel cathode (strip of 10cm x 2 cm) and put the solution and
the electrodes in a glass jar with a plastic lid, with holes in it for the electrodes and a hole in it for releasing gasses.
Theioretically, from 1 mol of NaBr I can make 0.5 mol of Br2. For one molecule of Br2 I need 2 electrons, so for making 0.5 mol of Br2 I need 1 mol of
electrons.
In the electrolysis setup, I run a current through the solution for such a time, that 1 mol of electrons is produced. I do this by applying 5 volts
across the anode and cathode, using an old PC power supply, and measure the current through the cell. Using Faradays rule, I find that for one mol of
electrons, 26.8 Ampere-hour of charge must be applied. I monitor the current through the cell every few hours and keep on applying current, until the
total Ah-value is around 27 Ah.
After this, I add 1 mol of H2SO4 (as 50% solution) to have all bromide, hypobromite and bromate reacted with each other and release the bromine. I
expect quite some bromine to settle at the bottom and use a pipette to take this away.
Given the fact that 100 ml of water dissolves around 3 grams of bromine, I expect that I can pipette away well over 30 grams of bromine, approximately
10 ml of bromine. The rest of the bromine will remain in the aqueous solution and as I do not have a suitable distillation setup for a corrosive like
bromine, I just pipette the bromine from under the aqueous solution.
I have a few questions about this setup:
- Is it realistic to expect well over 30 grams of bromine from the above setup, or would the yield be much lower? -
- Do you expect problems with a cell, having a plain plastic lid? I do not really expect problems because the bromine is not released as element in
the electrolysis cell (it reacts with hydroxide, formed at the cathode), but further thoughts on this would be appreciated.
- I assume that with 1 mol of electrons delivered by the power supply, enough bromide will have reacted for making bromine after addition of the acid.
Is this assumption correct or are there any losses, which I overlooked in the above procedure.
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With a post like the second description, there is a lot of detail, and then one can expect detailed responses. The first post only is an idea, nothing
worked out, it still is far from a real experiment.
So, I like the idea and would even like to go a little further, but I only like it if it is a discussion platform, based on truly worked out
experimental procedures and not just some ideas. If you have a nice idea, please work it out yourself before posting it as a proposed experimental
procedure.
psychokinetic - 10-10-2010 at 23:41
I don't know (and shudder to think, sometimes) what was going through Peach's purring brain, but I've got a feeling he's talking about what you just
said woelen
