Chemistry

I have learned 2 different opinions on 'work done ON/BY the system'. 1. When there is compression to the system, then it is work done ON the system and the value is positive. Whereas, when the system undergoes expansion, then it is work done BY the system and the value is negative. 2. When the system undergoes compression, the work done ON the system is positve value. While for the same situation, the work done BY the system is negative value. When the system undergoes expansion, the work done ON the system is negative value. But, the work done BY the system is positive value when the system undergoes expansion. I am so confusing on it!!!!

So...how do you carry out an experiment to test if these unknowns are covalent (polar or non-polar) or ionic? Unknowns: C6H12O6 --NaCl --CH4N20 --C6H8O7

I had a little debate with my teacher over this test question: One of the van der waals constants, a or b, can be correlated with the boiling point of a substance. Specify which constant and how it is related to the boiling point. Any comments? I thought it was b (atomic/molecular size), but apparently I was wrong...

Go to this link . It has a list of all the molecules with ridiculous, silly or just plain ridiculous names! http://www.chm.bris.ac.uk/sillymolecules/sillymols.htm

The first test tube with 10cm3 of 0.01M phenol, 10cm3 of bromide/bromate solution(0.0833M KBr & 0.0167M KBrO3) and 4 drops of Methyl Red are prepared. The second test tube fill with 5cm3 of 0.3M H2SO4. The two test tube immersed in water bath (75*C) and mix the two content of the test tubes. Repeat the experiment for 65*C, 55*C.........15*C. Some questions: 1. What is the function of phenol? 2. How much of the reaction between bromide and bromate ions is completed after time t? (what is the meaning and how to calculate??) 3. If the activation energy is doubled, would the rate of reaction be expected to increase or decease or remain unaffected? Thx ~

Both my teacher and I were confused in class today about ionization energies. Which is more difficult to ionize? Her notes say that a single electron in an anti-bonding orbital is the easiest to remove and a paired electron in a bonding orbital is the hardest. Is this correct? It seems logically that a paired electron would be easier to remove because it is being repelled already by the other electron in the pair. So it seems that a paired anti-bond should be easiest and a single lone bonded should be hardest. So which is it? She was unsure of the accuracy of her notes and we could not find this in the book so I wanted to get a second opinion. Thanks.

has anyone ever done the redox lab with the iron nail and copper sulfate, adding the NaCl and water? i was wondering if anyone knows the products that are formed in the experiment... one is what is the green color in the experiment? and what is the yellow liquid at the top of the solution? thanks

since at all times some water is dissociating as: [math] \ce{H2O <=> H3O+ + OH-} [/math] Could a substance [math]XA[/math] where [math]XA[/math] is a soluble gas or solid so that: [math] \ce{XA <=> X+ + A-} [/math] when combined with water. And that it then reacts as: [Math] \ce{X+ + OH- <=> XOH_{(g)} or_{(s)}} [/math] and where: [math] \ce{H3O+ + A- <=> H3OA} [/math] either does not take place or has an extremely small equillibrium constant so that the water's Ph goes down by using up the hydroxide without any additional acid? If so what substance would [math]XA[/math] be and if not, why not?

To all who celebrate Christmas, as I do, I hope you are having a merry one. If you celebrate something else, then I hope you are enjoying that too. Hopefully we all get something chemistry related for the holidays and we all have a good time. For me, I will finally be able to obtain a one-ounce sample of 24-karat gold for my collection. While I do have over an ounce of pure gold, it's in the form of tiny bars, smaller coins, and various pieces which combined equal over an ounce. It will be nice feeling the heft of one large gold piece in my hands.

I just realized that in my element collection, I have a sample of EVERY single element on the periodic table whose symbol is only one letter. H - Hydrogen: Gas discharge tube. D - Deuterium: Isotope of hydrogen which has been given a name/symbol. Gas discharge tube. T - Tritium: Isotope of hydrogen which has been given a name/symbol. Tracer key-ring. B - Boron: Amorphous brown powder and black crystalline lumps. C - Carbon: Graphite rods, amorphous black carbon, diamonds. N - Nitrogen: Sealed vial and gas discharge tube. O - Oxygen: Sealed vial and gas discharge tube. F - Fluorine: Sealed ampoule with about 15-25% fluorine gas and the rest helium. P …

My brother got a children science book entitled "100 things you should know about science". Well, I was reading it, and I noticed that it said that Helium have 1 proton and 1 electron. I got confused, because on the periodic table the atomic number for helium is 2. So I went to ask my sister and she said in "nature" all the helium atoms are bonded with hydrogen atoms, so it was why it have 1 proton and 1 electron. You guys concur with my sister? Or you have another theory? Thanks.

As I understand it, molecules form into shapes which space electron pairs so that they are as far apart from each other as possible. So, two elements bonded to a central atom form with a 180 degree difference between them, three form with 120 degrees. The part that confuses me is when there are four atoms around a central one. In that case, a pyramid is formed. I visualize this like it is popping up off a 2D plane and into three dimensions. My question is, if it can so easily "pop" into three dimensions in order to space the electrons further, why can't it pop into higher dimensions? Is my visualization all wrong?

Is there such a thing? A book that contains numerous syntheses. Google is a good resourse, but I would like to know if a hard bound copy exists. Thanks.

This is a funny, yet somewhat embarassing story involving the formation of an element. With last night being New Years Eve I went out and partied a little bit while ingesting some drinks which tend to give one a lower pH in their urine. This morning, when I awoke I went to sit on the crapper to let loose the food I ate last night and the drink I had imbibed on, I inadvertantly created an element. Shortly after "letting loose", I noticed a VERY strong chlorine gas odor and heard the toilet water hissing and fizzing. I stood up and saw a faint green cloud bubbling out of the solution and immediately started coughing. Apparently, a family member decided to use some ind…

Hi there everyone! Happy new year too you all first and now too bussiness... I was browsing arround Mozilla Firefox Update today and I found something some of you may be interested in: https://addons.mozilla.org/extensions/moreinfo.php?id=1236&application=firefox Its a periodic plugin for Firefox, could be useful for quick lookup of elements information Just though I'd share it with you, if anyone has any more please post those also. Cheers, Ryan Jones

I found a web site that is called science surpluss or somthin and i wanted to no how good there stuff is heres the link http://www.sciplus.com

i no a lot of you guys and girls use united nuclear so do you no if it uses any thing other thyan paypal?

Note too mods, there will be nothing in this thread relating too the making of other than that fact it should not be. I recently witnessed somone in my street messing with the Armstrong mic, I will not post a mixture configuration here because you cna guarantee that someone would use it. This stuff is dangerous, it ignited for no reason and is VERY sensative too touch and also many other things. The person (No names) continued too mix the stuff despite my warning, applied too much pressure and the mix ignited - he suffered 2nd degree burns to his hands and arms and had too be rushed too the hospital, luckily he was wearing gloves or it could have been far wors…

Okay, I posted this in the physics section but got no replies whatsoever. Perhaps it is better here: can a mod delete the post in the physics section? It has the same title. So, MagnaView Fluid, How frictionless is that thing? If I were to push a magnet covered in magnaview fluid in a plastic tube, would the friction between the fluid and the tube be greater or smaller than the friction between the magnet and the air if I were to push a levitated magnet? Is it possible to create a sort of "magnaview train" and push it and accelerate it using magnets? I'm planning on doing an experiment on this...

here`s a site I just stumbled across, and it gives the old Alchemy symbols for the THEN KNOWN elements as well as the known information about each http://periodic.lanl.gov/default.htm take a peek, it`s fascinating! Enjoy

Hello Everyone i am interested to know if any of you know of such a liquid that by any chance is very cold stay cold: D Thanks a lot

Why are all the values of electron affinity positive except for the group 2 elements and N?

Some new forums for all you chemistry geezers to enjoy Feedback etc appreciated as always.

H-C TRIPLE BOND C-H +Cl-Cl -----H-C = C=H Cl Cl Cl,Cl 240 KJ C,H 411 KJ Cl,C -327 KJ SO the total is 324 KJ Would this be correct? Thanks Joe

Nevermind