hermanntrude

A molecule is only one type of chemical.

it is a fairly roundabout way to make salt, but it's also a very fun way if you're very careful. before you start, read these: MSDS for sodium MSDS for chlorine gas then watch this video... the video is at the bottom of the page... dont be put off that it's in german. the video is self-explanatory, i think LINK

sometimes even just dissolving something causes heat to be given off. I once managed to boil a solution of NaOH just by making it.

to be honest with you, i'd suggest not trying to separate these two chemicals, since to do it you'd probably have to get one of them to 100% purity, which would be impossible and/or incredibly dangerous.

If you want to keep it reduced, keep it in some pure water with some iron filings or iron wool in it.

there are a few websites which will draw a graph of a titration curve based upon data such as Ka and Kb and so on. perhaps that'd be useful for you. Search google for "titration curve" or something like that

I have done this reaction myself, and I plan to do it as a demonstration for my class this year. It's very exciting, and if you do it carefully you can see the salt form on the surface of the metal before the flames and explosions start

snigger:D

of course. It could be self-assembly. anything containing sulfur would stick to the gold. It's not a chemical reaction as such but a strong bond is formed despite that. Never known it to turn the gold black, though... but I always used controlled conditions and small molecules

i suspect what has happened is the physical structure of the gold flakes was somehow affected by the process, making it thinner and hole-ier. Finely divided metals often look black.

i suspect this is homework. I'll move it to homework help. Apologies if it is just an enquiry

Fair enough. I was thinking about sublimation as being exclusively going from solid to gas without any appreciable melting, but that's the wrong definition

iodine is unusual, for sure, but contrary to popular belief, it doesn't really sublime at normal pressures. It is a solid at room temperature, and strangely for a solid, it has an appreciable vapour pressure, which something most solids are considered not to have. As you raise the temperature, that vapour pressure increases, but as long as you have plenty of iodine, you can raise its temperature to the melting point and melt it just like nearly any other solid. Of course by that time there'll be an awful lot of vapourised iodine hanging around. Not unlike bromine there.

or in your lungs, eyes, ears, stomach or nose. basically, be very careful

cesium, by far. It's cool. check out alt.cesium

It helps to remember what science fairs are judged on. Think about what the judges want to see and what they are likely to have seen before. If at all possible, give them something that's completely new to them. If not (which is most likely... research is hard to do at this level), make it well-thought-out. Be scientific from start to finish... have an experiment, try to make it one which you don't already know the result of, record every step and try to explain your results. As for ideas I couldn't resist giving you one how about something to do with g-forces? Astronauts are well known for having to deal with high g-forces. Perhaps you could experiment with g-forces and how to minimise them or how to deal with them better? I suspect eggs would be useful as experimental subjects

you'll probably need the kind of temperatures you'll get with dry ice (-78°C) or even liquid nitrogen (-196°C), and it might still be a bit runny or sticky

I've got 17 identical bottles of bromine in my lab, none of which are stored under sulfuric acid. I think it's OK to omit that part

so if I already have 512, perhaps I should buy 1Gb and then if it works with the 512 i have 1.5 Gb and if it doesn't I've still upgraded...?

what's the significance of the frequency? The RAM I already have is 200MHz, but they don't sell them with that low a frequency now

OK so CPU-Z did what I needed. I now know I need DDR-RAM, and that my maximum bandwidth is PC-3200 at 200MHz So is there anything else I should know before i just go and buy some? or are there other specs? what's a good brand, or does that depend on my computer?

I want to upgrade my fairly old computer by doubling its RAM from 512 Mb to 1Gb. I don't know what the motherboard is and i'm not sure how to find out without opening the box and reading it off the board itself. I'm vaguely aware that there is probably more than just one kind of RAM available and the last tiem I did this was about 8 years ago on another computer. any advice?

depending on how advanced the course is and just how far your students are likely to delve into chemistry, one good way is to show them atomic structure as far as the bohr theory (which like so many things in chemistry is wrong, but a very useful lie), then consider the hydrogen atom, and ask them what effect changing the number of electrons would have, then repeat for protons and repeat for neutrons. This gives them a good idea of what it means to have a proton number, a charge and a mass.

I moved to newfoundland nearly a year ago. Newfoundland's provincial plant is the pitcher plant: Recently I discovered that they also have the sundew plants here... This is the only photo I didn't take: And last week I found out we also have the round-leafed variety of sundew: I am now completely fascinated in these things. I read somewhere that the sundews can actually wrap themselves around their prey by growing. Some of them can apparently bend themselves 180° in one minute in this fashion. Is that possible?

catharsis, you're going to enjoy reading up on basic chemistry. Start at high-school level and work upwards as far as you like. you obviously have an enquiring mind. You were wrong that Na and Cl are parts of water, although their ions [ce](Cl- and Na+)[/ce] are often found IN water, since sodium chloride is incredibly common and very soluble in water