Ethanol & Permanganate experiment

[vlclabbie]

Hey everyone! Hope all those on their holidays are enjoying themselves & those who aren't ... will be soon! Have a great time!

I've just gotten home from a 4 day chem residential at uni & they mentioned a prac they do for high school kids (demo only) where they pour ethanol onto potassium permanganate crystals. Apparently it's a specky one.... anyone know anything about it?

I know of the one you do with sulphuric acid & ethanol in layers in a cylinder... then add the crystals... Not after that one.

Thanks!

[RosalieM]

Might be similar to glycerol and potassium permanganate which starts a fire. You only need a very small amount and a big cleared area. I think teachers here do it as a demo in an evaporating basin or maybe on a heatproof mat. It spits a bit too.

[Whspa]

I found this on the internet - I think it's from the University of Queensland (uq.edu.au)

14.1.8 Test heat of reaction, with potassium permanganate with ethanol
BE CAREFUL! This is a dangerous experiment Use very small quantities and follow your safety rules. Remember that strong oxidants should be stored separately from flammable organic chemicals.
Add alcohol to cotton wool in an evaporating basin. Dip a glass rod into concentrated sulfuric acid, then touch crystals of potassium permanganate. Touch the cotton wool with the glass rod. Be Careful!
The heat from the formation of manganese (VII) oxide on the glass rod ignites the alcohol.

[lizzieb]

Great avatar, Whspa!

Just how I feel when someone surprises me.

Wish I could drop off for a snooze right now - so tired ....

[Whspa]

Well, Liz, I was inspired by yours to go looking.
Carol

[trish armstrong]

Ohh be so careful,
My teachers did this two weeks ago to demonstrate to yr12 chem, anyway we kept it in the fume cupboard for two days,
crackled and popped for a day and a half, was pretty watching little explosions in the glass measuring cylinder.
Anyway after two days they said all reaction had finished and trish can clean up.
Well consulted Csis package and all those chemicals can be safely tipped down sink with irrigation. Was concerned about them mixed together, anyway, started the process and as soon as it touched water I had a ball of flames come up and singe the hairs of my arm above the gloves.
Soooo cranky that the teachers didn't explain anything to me.
If it is the same prac, be careful cleaning up.....
I told them that they are not to do it again without the HOD signing off on it first as I don't think the risks were really consulted, and I had a feeling that it may be close to being a banned experiment.Don't know.
Most of the time I don't get consulted on experiments,Kept in the dark, so was a little upset when safety of all(me included) wasn't prioritised.
Trish.

[vlclabbie]

Yeah... I wondered that too Trish... I did know about the ball of flames on tipping it out - since you're increasing the interface between the two liquids but this is the one in the measuring cylinder.

The one I'm after isn't supposed to be as scary as all these! I wouldn't want to demo any that spit & fume for days... or that singe arm hairs!!!

Perhaps it may not be officially banned but one of those that isn't worth the trouble?!!!

Thanks for your help everyone! Back to the drawing board!

[franco]

And Trish's scare above is one of the main reasons so many pracs (and other things) are being canned these days, or wrapped up in so much paperwork it's not worth the trouble. I'll bet the same teachers that repeatedly fail to adhere to safe procedures and practices are the first ones to moan when pracs are banned. If we all follow the correct procedures and complete thorough risk assessments, I'm sure that many 'banned' pracs could still be safely performed.
I think most of the paperwork and OH & S stuff comes courtesy of the cowboys who think the rules don't apply to them, plus the over-the-top, often unqualified people, who are only interested in building empires. The rest of us - the majority - are caught in the middle of this crap and ultimately it's the students who miss out.

Cheers,
Fran

[vlclabbie]

Standing ovation from me Fran

[RosalieM]

http://www.youtube.com/watch?v=T15kCaPDT9I

I just found this (for those of you with youtube access) - shame it's too late for you, Trish!

[Lis]

Hey Fran,
Have you been at my school? seems you are describing 1 of the teachers here.
cheers
Lisa