hermanntrude

i see. Well I don't have any tin compounds, only tin... I imagine some SnO2 wouldn't be expensive, though, and tin's melting point is a LOT lower. Can you make bronze by using a mixed ore?

i'm going to make "stretching the imagination" part of the fun of it. "I'm going to take you through the discovery of copper. This is going to take some imagination, since we're in a college, in the year 2009, and we're all wearing clothes... however, chemistry's like that... you need to use your mind..." Merged post follows: Consecutive posts mergedOK so i tried it out with malachite (basic hydrate of copper carbonate), and it worked quite nicely. Obviously copper there but as a powder rather than a solid lump. Obviously you CAN do the smelting at a lower temperature than the melting point because my copper didnt melt and coalesce into a lump (which is what I hoped for). I have another bunsen burner with a bigger nozzle... perhaps it'll make a hotter flame?

i've never been to fogo, but it's easy to see why they got the idea when you step out onto the edge of some of the islands round here, stuck right out into the north atlantic

it may even be an advantage, in that many students when faced with a chemistry problem will immediately try to throw an equation at it, without ever attempting to actually understand the situation, and then they end up using the wrong values in the wrong places. I much prefer a student who's not so good at math but can understand a situation given in a question (or even bother to read the damned thing) and of course, now you know a chemistry instructor :0)

The island of Fogo, not far from here, is supposed to be near one of the corners of the earth

not really. It's an excel spreadsheet which uses a random number and the "lookup" function to look up a student name from a list and then displays it in large text in another cell. The only programming is involved in the button which makes it recaculate it fifteen times so that the names flicker through lots of choices before settling on one... just for fun. there is a bit more programming in the attendance-taking section but it's all recorded macros so i never really had to learn any visual basic.

why wouldn't you define the transition metals as acids? if they accept electrons, then at the very least they are Lewis acids. The very term "acid" is man-made and doesn't correlate to any universal law or universal substance. It is defined by the three theories taught in schools and therefore anything which fits those definitions is considered an acid.

the advice in education courses is to have a standing rule in your classes that no-one should answer without being named ("no class answers, please"), and that you should ask the question, then wait between 5 and 15 seconds depending on the level of complexity of the question, then name someone. That way everyone thinks about the question

had you considered simply using something based on photographic film? silver nitrate is used, and it will darken quite quickly even under fairly feeble light sources, as long as they are more energetic than red light. does it need to be food-safe?

benzene is more polarisable than cyclohexane i think, because of its delocalised electrons... i may be wrong...

I dont intend to do any thermite reactions yet and certainly never in a testube. Would this reaction work with malachite (basic cupric carbonate)? I think that the carbonate would decompose to form the oxide which would then form the copper. I am thinking of doing a demonstration about the discovery of copper, pretending people are cavemen and turning out the lights and stuff like that. I have a dramatic script in mind

I want specifically to do the reduction using carbon

not what I meant. I meant if you turned all the hydroxy groups into carboxylic acid groups, what would you have? it's basically citric acid with one hydroxy group removed.

what's the name of the acid formed by oxidation of glycerol anyway? it may have a low boiling point because of dimer formation

Can you link me to a write-up or describe the procedure for me? Really? bunsens get that got? i thought they managed about 700°C tops.

actually they don't always land on their feet but they do have a pretty nifty way of rotating in mid-air and at least trying to land on their feet if given the chance. I forget where I saw it now... hmm I found it... here's the link

no biggie, kroughfire. Welcome to the forums :0)

Time and time again, people post here (in these forums) thinking that electrolysis will magically break up any salt into its component parts in aqueous solution. It wont. Especially if your salt contains very reactive metals. Particularly metals which would normally react with water.

if you only have a few data points, just use a histogram. If you have a lot of data points you could use a scatter graph and add a smoothed average trendline. Excel also has a number of statistical functions, at least one of which will probably allow you actually calculate the area under the graph.

generally reduction potentials are reserved only for pure substances, such as the elements or compounds. The earth (the planet) and earth (the soil under us) are both heterogeneous mixtures, which are very complex and hard to assign an exact reduction potential to. However, you could come up with some kind of average based on how oxidising/reducing the soil was. It'd certainly differ in different places and probably even from one square meter to the next.

apparently some smelting can be done at lower temps than the melting point of the metal itself. I wanted to know which metals would be the easiest for me to try. I live in an area with a lot of copper ore... Although I've already pretty much ruled that out... i think it requires 1200°C, which is probably more than i can achieve

what's the lowest temperature smelting I can do and can it be done with a bunsen?

Kroughfire, welcome to the forum. Please check our policy on answering homework questions. Please also review our rules and hazmat policy before posting any more. We do not give out the answers to questions but help our posters to find the answers for themselves.

swanson, my textbook seems to be using inertia in linear systems... is it because it doesn't use the word "moment" that it's OK, or is my textbook wrong?

what creationists and scientists always seem to forget is that science and logical thought do not require us to know the answer to everything to remain valid. "I don't know" is a perfectly respectible answer.