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Geology, Palaeontology & Archaeology / Re: Why is there bituminous coal in the river Thames?

« on: 23/07/2014 13:39:05 »

Yes, I just had a brief walk and found lots of rather big pieces, including a 20x20x20 coal cube, I guess there really are hundreds of kilos in there... Thank you for the information, I'll use it for some expreriments and as a sample/free souvenir from London, lol

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Geology, Palaeontology & Archaeology / Why is there bituminous coal in the river Thames?

« on: 22/07/2014 13:41:31 »

So I'm on holiday in London, and walking by the southern bank of the river Thames (Tate/OXO Centre Area) I noticed some black pebbles on the small beach, next to the river. Upon collection and examination of the "rocks" it turn out it's bituminous coal, so lignite, organic matter, basically. The thing is there is quite a lot of it, all eroded and shaped in pebbles. Why is there coal in the Thames?

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Chemistry / Re: Is bio-ethanol a valid substitute for tech-grade ethanol?

« on: 04/04/2014 17:33:53 »

Uhm, I'll look for the prices of methanol and ethyl acetate. I already have acetone, but it evaporates too quickly.

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Chemistry / Re: Is bio-ethanol a valid substitute for tech-grade ethanol?

« on: 04/04/2014 14:45:42 »

In Italy reagents are usually sold by Carlo Erba Reagents, or by smaller industries. I can ask a chemist the price/to order some as a school/educational facility, but bureaucracy (checking the supplier, asking the ministry for refund, getting permissions, confirming the purchase, ask for payment, actuate payment, shipping) drags the whole process for months (my school ordered some reagents in Sept 2013 and they'll arrive -we hope- in June 2014).

And nope, all reagent industries/manufacturers sell&ship only in bulk, both reagents and glassware. The only way is to find a secondary seller, big enough to have low prices and small enough to sell individual items.

I've asked for some purchases a company re-selling plastic/glass labware and containers that declared on their site "we are available even for small orders" only to find out that a "small" order is no less than 50-100pcs. That would be like 30€ in plastic lab bottles, but where am I going to store them all? They'd probably last like 5 generations...

About reagent companies, they all ask for your profession, company name, role and so on. Even to request catalogs or free posters you must insert your company name... I obviously can't lie inserting my CF (fiscal code) saying I'm a teacher or a private who owns an analysis lab.

At the moment I'm using ethanol to prepare vegetal extracts as pH indicators, but it is always useful. How about I keep the 500mL I have (96%, food grade) in its bottle and I use bio-ethanol as solvent?

Are there other good solvents for extracts? Like acetone, cheap and (quite) safe?

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Chemistry / Re: Is bio-ethanol a valid substitute for tech-grade ethanol?

« on: 03/04/2014 18:06:42 »

Yep :3 I'll do it once I'll have gathered better equipment and maybe in my friend's lab in pair with the supervision of a chemist. Assuming now it's be safe, let us not forget that

Distillation is almost certainly illegal.

Just cheked, It's illegal unless you pay some permits/taxes. I guess I'll be giving money to the ol' fellas in Rome anyway, I'll look it up at a bigger chem retailer.

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Physiology & Medicine / Re: Why do we feel pain coming from the brain, if there are no pain receptors?

« on: 02/04/2014 21:50:34 »

So the pain comes from the external surface, not the inside... Thanks!

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Chemistry / Re: Is bio-ethanol a valid substitute for tech-grade ethanol?

« on: 02/04/2014 20:30:42 »

Before legality, I'd think about safety. And honestly, distillating a solution of >98% alcohols doesn't seem safe at all. I'll check the composition of bio-ethanol and evaluate if it can be of some use. Thank you all!

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Physiology & Medicine / Why do we feel pain coming from the brain, if there are no pain receptors?

« on: 02/04/2014 15:52:49 »

This is a really dumb question. I've always been told that the brain has no pain receptors, allowing people to undergo open-head surgery with only anesthetic acting on their skin/bone tissues.

Why do we feel pain when we have headaches? How about chronic headaches? You can even feel which part of the brain is it coming from...

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Chemistry / Re: Is bio-ethanol a valid substitute for tech-grade ethanol?

« on: 02/04/2014 09:44:12 »

The isporopanol is either sold pure for about 7€/L -very rare to find- or fruit/flower parfumed for 1-2€/L, only sold in huge DIY retail stores, and I don't trust parfumed products at all, I don't need more variables that can make my activities fail.

I found two MSDS, one says it's pure ethanol (CONTAINS: Ethanol), the other says there's 96% ethanol, 1% MEK, 0.008% denatonium benzoate.

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Chemistry / Re: Is bio-ethanol a valid substitute for tech-grade ethanol?

« on: 01/04/2014 20:26:27 »

So It's negative both for denaturated and bio-ethanol? That's a shame, it was relatively cheap...

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Chemistry / Is bio-ethanol a valid substitute for tech-grade ethanol?

« on: 01/04/2014 14:28:28 »

Can bio-ethanol -the transparent one sold sold at hardware stores- used for simple experiments in place of technical grade 96% ethanol? I wouldn't mind buying it from my chem supplier or in a supermarket, but the Italian govt imposes a heavy tax on food grade/edible ethanol (1 liter costs 3€ for the alcohol + 15€ for the state monopoly, so for 18€=20$ I can get much more stuff). How about the denaturated one? It's bright pink, and I profoundly doubt it can be of any use.

The European Union agreed in February 2013 to the mutual procedures for the complete denaturing of alcohol:
    Per hectolitre (100 L) of absolute ethanol: 3 litres of isopropyl alcohol (IPA), 3 litres of methyl ethyl ketone (MEK) and 1 gram denatonium benzoate.

  http://en.wikipedia.org/wiki/Denatured_alcohol

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Physiology & Medicine / Dangers of sodium bicarbonate intake?

« on: 31/03/2014 15:00:31 »

Can sodium bicarbonate affect your health? For example, what would a saturated glass (150 mL) do to your body and digestive apparatus? What about a daily intake, let's say 1/2 table spoon? Putting aside all the alkaline diet bs, what is the real effect of an excessive intake of sodium bicarbonate?

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Chemistry / Re: Best method for production/storage of Schweizer's reagent?

« on: 30/03/2014 09:59:34 »

Yes, that's why I'm asking. Sources on the net say it can be also dried out but I am not convinced of its usefulness at all.

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Chemistry / Best method for production/storage of Schweizer's reagent?

« on: 29/03/2014 20:58:12 »

What is the most practical method for producing and storing Schweizer's reagent [Cu(NH₃)₄(H₂O)₂](OH)₂? Should I follow the

CuCO₃+NaOH -> NH₃ procedure or the CuSO₄+NH₃ -> NaOH?

Is it more easy and practical to dry it out or to store it liquid? Will it release ammonia gas both in the crystalline and the aqueous form? What if stored with cellulose dissolved in it already? Will it preserve longer?

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Physiology & Medicine / Re: Toxicity of metallic lead to touch?

« on: 28/03/2014 13:13:07 »

I've melted quite some tiny pieces of metal in one round, coin-like block so a couple of people asked me to show them the result and the crystal-like shape on the top, and they all said I should be wearing gloves to handle it  because it's poisonous. I'm not using it as a necklace or anything, and I guess occasional handling isn't a problem.

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Chemistry / Re: Cleaning scrap Lead (IV) Oxide?

« on: 28/03/2014 13:08:07 »

Keeping some and making either Pb₃O₄, PbCl₂ or Pb(NO₃)₂. I've sketched this diagram showing the possible reactions, though not necessarily practical (e.g. calcinating at 600°C or Na₂[Pb(OH)₆])

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Chemistry / Re: What is in the white powder sold as "Chemical Chimney Cleaner"?

« on: 27/03/2014 17:59:15 »

I found an alternative brand with the ingredient(s) shown. it is NH₄Cl, thought it's not worth the purchase. 13€/kg, it's probably cheaper at a chem supplier.

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Physiology & Medicine / Toxicity of metallic lead to touch?

« on: 27/03/2014 17:53:25 »

So, I keep hearing people saying how touching metallic lead poisons your body. I am aware that lead compounds are (neuro)toxic, for example Pb₃O₄. Is metallic lead toxic to touch? It seems pretty exaggerated to me, it has always been used for water pipes (etymology of plumber) and other common items. So yeah, what do you know?

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Chemistry / Re: Cleaning scrap Lead (IV) Oxide?

« on: 27/03/2014 17:37:46 »

I have a waste container for experiments involving chromium, lead, tin etc that's going to be disposed of by some company. I mostly use salts/acid/bases and common chemicals, that can be just neutralized and poured down the sink. I've prepared the bucket with the slurry PbO₂, I hope it'll work fine.

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Chemistry / Pigment of purple violets as pH indicator?

« on: 26/03/2014 19:46:30 »

What is the pigment in purple violets? Does it decompose over short (hours) periods of time?
I've prepared a solution of 120 mashed purple violets in 100mL ethanol, as a pH indicator. The solution was purple/blue when I was preparing it, but after a day in the dark it became olive-yellow/green. It now turns bright yellow in acids and bright pink (like phenolphtalein) in bases (now that I think about it, it may be the opposite).
http://en.wikipedia.org/wiki/Viola_odorata
Anyway, why did it decompose? Do you have suggestions on possible natural pH indicators? When June/July comes I'll try with sambucus berries, they have an interesting deep black/violet color.