liambob1

I use a 4:3 Ethanol-hexane solvent myself

My point in bringing up that article was to demonstrate the absurdity of the notion that natural chemicals are not toxic. Its one of the fundamental concepts of pharmacology and toxicology: "Everything is toxic in high enough doses" Except chemistry, you can never have too much chemistry.

That is a very simplistic view of the topic, a lot of the chemicals found in the products you mentioned do occur in nature. Furthermore to imply that chemicals found in nature aren't poisonous or caustic is just plain wrong. Caustic simply means it causes corrosion, and quite a lot of chemicals found in nature have that property. There are plenty of "natural" chemicals which can kill or corrode things. I recomend you read this article http://www.pnas.org/content/87/19/7782.full.pdf+html

Hey guys, I decided to try and make Benedicts reagent for the lulz. My first step is obtaining Sodium Citrate but I have an issue I hope you can assist me with. I reacted citric acid and sodium bicarbonate to produce sodium citrate water and carbon dioxide. In a moment of stupidity I decided to add ethanol to the product to try and force the salt to precipitate rather than just evaporating off the water. I then attempted to evaporate off the water and ethanol and all was going well till about 80oC when this happened: My theory on this is it is a side reaction involving Fe contamination in the water. I tested the water I used and it was about .02 mg/L Do you think it was an iron side reaction or what else could have happened. The result is a black smelly liquid which I am having a hard time evaporating off because every time I do it erupts like this. Is there a way to rescue my salt? Cheers

Its the Ester of Ethanol and acetic acid CH3CH2OH + CH3COOH ⇌ CH3COOCH2CH3 + H2O You can also find it in decent quantity in non-acetone nail varnish remover <br class="Apple-interchange-newline">

So I am currently on my industrial placement as part of my pharmacy degree, here In Ireland the plan in the next few years is on the drug payments scheme, long term illness and government prescriptions, pharmacists will automatically dispense the cheaper Irish made generics in order to save the government money on these schemes, and if the customer wants to go with the brand name drug they have to pay the difference themselves. The company I am working for is already trying to switch people over to the generics to the change wont be too sudden however we are encountering a lot of resistance, particularly with older people. What are everybodies thoughts on this? Should people be entitled to have their brand name drugs on the schemes if they say they feel it works better, even if this effect is nothing but the placebo effect?

If its the same video I saw pay attention to the start where he says this is a highly dangerous reaction that produced a highly flammable product and a highly toxic product using enough heat to give you a third degree burn and he used a powerful fume hood and full face mask, he himself said nobody should attempt the reaction themselves

That's a good point, the whole reaction, is very dangerous without the proper equipment and training, so don't try this at home

yeah this reaction is basically: Crazy bad dangerous stuff + crazy bad dangerous stuff = HELLA crazy bad crazy dangerous stuff

According to wiki the best reaction formula is 2CH4 + S8 → 2CS2 + 4H2S Using Natural gas as the carbon source in the presence of silica gel, requiring 600 °C This method has all but replaced the charcoal method due to price and high temperature, you should be able to do it but it would require temperatures around 850 oC And be careful because as I am sure you know it is highly flammable and has one of the lowest autoignition temperatures around 90oC Here is an interesting Article from way back

Managed to get another 9 grams from the waste water but I appear to have two different types of crystals. Why is this?

I just dissolved it in water and then recrystallized and now im only left with 7.8g of sodium acetate! just from recrystallization. That is a pretty poor experiment right there

So I decided to make sodium acetate at home, just for giggles. So here is the equation : CH3COOH + NaHCO3 → CH3COONa + H2O + CO2 My yield was 27g of sodium acetate which when cooled turned into pretty crystals as expected. But here lies my problem, when I tried to heat it up to turn it back into liquid sodium acetate all the crystals do is pop and hiss and crackle. The melting point of sodium acetate trihydrate is 58o so it should work. My thinking on what happened is I left the crystals out overnight and when I put them on my balance the mass was 24.7. That is a loss of 2.3 grams overnight. So I thought maybe what happened is due to the heat my sodium acetate trihydrate may have turned into sodium acetate anhydrous with the loss of water accounting for the loss of mass. The melting point for sodium acetate anhydrous is 324o which would also explain why my crystals wont melt. What are your thoughts on this? Are my conclusions correct and if so how can I save my poor sodium acetate? Any comments are appreciated

The octet rule applies to main group elements and to metals. But there are some stable except Helium has 2 electrons in its outer shell and is very stable, Hyrdogen only needs an additional one to achieve stability. In transition methods the octet rule does not apply and is instead replaced by the 18 electron rule .

It did indeed, I've been trying to join there and there must be a way for Irishmen to do so since there is a branch here but I cant seem to find it

So I was right? Essentially what the methods consist of is making up standards of increasing concentration and then adding a definite amount of the sample of unknown concentration then plot the original concentration vs the instrument response and extrapolate the graph to get the unknown concentration? If thats right it an awful lot simpler than I thought.

So is this Correct? where the line crosses the x axis on the left hand side is equal to the concentration? Don't these points of data make a beautiful line?

as far as I remember we prepared 5 standards each containing 2,4,6,8 and 10 mls of a 100 ppm stock and then added 25 mls of the sample of unknown concentration ran each in an AA obtained a graph and extrapolated the line to give the concentration of the unknown sample, does this sound correct?. I still have the data somewhere if it would help

I'm just trying to remember how standard addition works exactly

So Im having a bit of trouble remembering how standard additions methods work and after going over my notes its still unclear. I know you have a sample of unknown concentration in a complex matrix so you add a sample of known concentration of the same type as the unknown and then somehow extrapolate the unknown concentration. I know its very simple but I cant seem to remember. If I remember correctly I did an experiment involving this and the concentration of iron in water. Can someone help clear this up?

The acid is defined as the molecule or ion that is able to donate a proton, and it follows that if the proton is donated that there has to be a species that accepts the election which is called the base. So now have a look at your reaction and see which gains and which looses a proton. acid + base conjugate base + conjugate acid.

We buy in the plates pretreated to fluoresce. Thanks

I think the idea was the plate fluoresed and the sucrose didn't therefore the spots were the sucrose was were identifible because they didn't fluorese while the rest of the plate did

The plates were treated so that they would floresce under uv light and so the spot where the sample was would not floresce and thus we could see the spots. Also the solvent front was advancing very very slowly in the second plate, the assistant said this is why water should never be used as part of the mobile phase, so maybe that effected it. Also is it permissible to use the same solvent you disolved the sample in as your mobile phase?

We did this lab today but it didn't work out very well. The sample we had to analyze was sucrose, so we dissolved it in ethanol and used ethyl acetate as the mobile phase and the tlc plate with silica as the stationary phase, the solvent front went up but no spots were detected. In the second part we dissolved and l-aspartic acid the sucrose in water and used 15 mls of ethanol and 10 mls as the mobile phase and the tlc plate with silica as the stationary phase, but that didnt work either! What went wrong?