hermanntrude

the pH scale is really only applicable to aqueous solutions, since it is the negative logarithm of the concentration of hydronium ions. Now while there will be a few hydroxonium ions in any solution, no matter how dry, unless there is a VERY significant impurity in the non-organic solution, the concentration of hydronium ions will be very very low indeed, which, in an aqueous solution would translate to a high pH (perhaps 13 or 14), which would also mean that the hyoxide ion concentration would be very high, which would mean the solution was basic and probably highly corrosive. This isn't true of our non-aqueous solution, though, since there may be no hydroxide ions at all or, more likely, exactly the same amount as there are hydronium ions, meaning the solution is actually neutral. Remember that in an aqueous solution, pH and pOH are tied together via PKw (PKw is the legative logarithm of the equilibrium constant for the auto-ionization of water ([ce]2H2O <=> H3O+ + OH- [/ce]). pH + pOH = pKw = 14), but this doesnt work in a non-aqueous solution because any water that is present is an impurity and therefore part of a mixture rather than a pure aqueous solution.

P4o10?

we've had multiple queries about the synthesis of ethanol gel. Use our search function.

theo, this isn't new, the last post, prior to aadhar's was in april. I'm sure dave won't mind some extra rep anyhow, though

Just a few notes about that article: 1) no references at all. How do you know that "chlorine has been linked to asthma"? for instance? was it a study performed using the scientific method, or was it that someone drew the two words on a whiteboard and then drew a line linking them together? 2) repeated mentions of chlorine in water do not state what form the chlorine is in. Is it molecular chlorine, [ce]Cl2[/ce]? or perhaps chloride ions? or the perchlorate ion? who knows? Probably not the author of the article. 3) the statement that chlorine can form "THM"s shows the author's lack of common sense as well as knowledge. Since chlorine is the halogen present the only possible THM is chloroform. There was no need to use the general term "trihalomethanes", and certainly no need to go evoking an acronym.

Please be aware of our rules, particularly those concerning quoting other people's work. Link to the source of that text please, and don't quote things un-cited again. Thanks. If there is a moderator around, perhaps they could insert this link: http://www.howstuffworks.com/battery.htm/printable

if you do happen to ingest any methanol, the first thing to do would be to get roaring drunk

OK you need to re-read your notes on the reaction quotient, Q. The reaction quotient can be found by basically doing the same math as you would to find the equilibrium constant, but with non-equilibrium concentrations (or at least, concentrations you don't know are at equilibrium. If Q>K, the reaction has gone too far and the reverse reaction will be favoured. If Q<K, the forward reaction will be favoured. A method many students like to use is to put the K first, so that the arrow (greater-than or less-than sign, < or >) points in the direction of the reaction that's favoured. If Q=K, the reaction is at equilibrium already. bear in mind you can only compare Kc with Kc and Kp with Qp.

haha i guess i didn't spot that bit, eh? Oh well. if by some remote chance, a member uses the search function and finds this thread when looking for help determining polarities of molecules, now they'll have a full answer. ShadowReeves, we don't give out the answers here we try to help people find it themselves. Plus your answer was only one of many. there's more than one.

of course, it's widely accepted that all the elements up to 118 (except 117) have been discovered. It's just that IUPAC is a bit slow on recognising these things

I have ennui for breakfast

didn't we already have this very same post from a different member?

Hmm well it's not exactly what you're looking for but oliver sachs's autobiography "uncle tungsten" has a lot of historical chemistry info in it as well as some awesome descriptions of the love of chemistry

magnesium is fairly predictable too, and i have tons of the stuff

I have to say i was quite pleased with it myself

I ended up just buying a premixed thermite, because it was actually cheaper than the separate components. I prefer magnesium ribbon because it avoids any confusion to the students. They might imagine that the potassium permanganate and glycerin are somehow involved in the reaction. Plus of course the ribbon adds to the drama, makes it look a lot like a fuse on a bomb.

no-one's in favour of that. /kick ydoaPs

about about quetzelcoatlium? then we could have a chemical symbol with a Q in it, which would be useful in making words out of elemental symbols

condensation isn't a reaction. Condensation is a physical process. When you cool a gas, there is less kinetic energy in the system, meaning that, on average, the molecules are moving slower. All molecules have an attraction for each other. In some molecules the attractions are larger than others, but there is always an attraction. When there is less energy available to the molecules, they are more likely to stick together and form a condensed phase (liquid or solid). There is no energy associated with "cold" cold is simply a lack of heat and heat is thermal energy, related to kinetic energy. Imagine you have a bag of weak magnets (imagine for a minute that they only attract each other, not repel). If you leave the bag alone the magnets will stick together. if you start moving the bag about a bit, the magnets might slide over each other, because you've given them some energy, but not enough to make them separate from each other. Now imagine you give the bag a really good shake. While the bag is shaking, the magnets will all fly around inside the bag, hardly sticking to each other at all. That's because the energy you're providing is a lot more than the energy of the attractions between them. That's just a metaphor, not the real case, but it might help to understand.

John, you're being a bit of a pedant. While it's true that ammonium hydroxide has never been isolated, most aqueous solutions of ammonia are still sold under the name of ammonium hydroxide. It's annoying, but true. So perhaps if we re-word the question "does ammonia in water, which is usually called ammonium hydroxide despite the fact it doesn't actually form ammonium hydroxide, react with aluminum?", then you'll answer the poor fellow's question?

Did that help, then? I was bored that day... you were lucky... lol

surely the easiest way to add oxygen is simply to bubble some through it. not sure about H2S removal, but i bet there are some in the forum who'll know.

if a molecule is polar, it will exhibit dipole-dipole interactions, which are (usually) the weakest of the three commonly-quoted intermolecular forces. Check your textbook for a complete list, try a few questions on the subject and then come back with specific questions if you have any.

the Lewis structure provides no information on the molecular geometry, althought it is certain the first step. -draw the Lewis diagram (look in your textbook and notes for the rules to complete this step) -use VSEPR to determine the electron group geometry and then the molecular gemoetry (again, info on how to do this will be in your textbook and notes) -the last step is often the hardest. If you've studied vectors it helps, because then you can simply treat the dipoles on each bond as vectors and combine them to see if there is a resultant vector (resultant dipole). Otherwise try to look for asymmetry. If a molecule has an asymmetric shape (T-shape, trigonal pyramidal, etc), and the bonds involved have dipoles on them, there will be a resultant dipole. If the shape is symmetrical but the outer atoms are different to each other (chloromethane is a good example), then there will also be a dipole.

pigweaselium