jdurg

Actually, when referring to precious metals any mention of "ounce" is referring to the troy ounce weight scale which is a bit different than the avoirdpoidus(sp?) system. One troy ounce is equal to 31.1 grams. In older computers, they used to use a great deal of gold for the circuit board pins and various other components. Once manufacturers realized that you got the exact same results when you used a micron thick plating, they quit using actual gold wire and moved to an incredibly thin plating. Therefore, modern computers contain maybe half a gram of gold total if you are very lucky. In order to make it remotely profitable, you need to amass a MASSIVE, and I mean MASSIVE pile of old chips and circuit boards and be able to recover all of the gold without any loss otherwise it's just not worth it.

"-ic" denotes a higher oxidation state of the ion being referred to in a compound. If you have Cupric Sulfate versus Cuprous Sulfate, then it means that the copper ion is in a higher oxidation state in Cupric Sulfate than in Cuprous Sulfate. The easy way to remember this is sulfurous versus sulfuric acid. Sulfurous Acid is H2SO3 while Sulfuric Acid is H2SO4. In the "ic" acid, the sulfur atom is in an oxidation state of +6 while in Sulfurous Acid the sulfur atom is only +4. "-ites" and "-ates" are pretty much the same thing as the -ous and -ic naming in acids, only these are specific to oxygen containing anions. (I.E., carbonate, nitrate, carbonite, sulfite, permanganate, etc.) The "-ate" designation means that the atom being referred to is in a higher oxidation state than the analogous "-ite" version. If you look at Nitrate (-NO3) versus Nitrite (-NO2) you'll see that the nitrogen atom in the nitrate ion is in a higher oxidation state than it is in the nitrite ion. The same with sulfate (--SO4) and sulfite (--SO3). "-ide" just denotes a solitary atom with a negative charge. Hydride means a hydrogen atom with a negative charge. Sulfide is a sulfur atom with a negative charge. All of them are mononuclear ions with a negative charge. Hence why calling the f-block elements lanthanides and actinides is just plain wrong. The only acceptable naming is lanthanoids and actinoids since they are not all negatively charged ions of lanthanum and actinium.

For descriptive symbol I believe he means (g), (l), (s), (aq), etc.

I received my Bachelor's of Science in Forensic Chemistry. The degree taught me about thinking "outside of the box" and quite analytically. I now look at the big picture more than ever before and try and see every possible problem that can arise. While I never got a career in chemistry (as honestly the chemistry field is very limited in terms of jobs and actually quite boring), everything I learned really helped me out in my current career path. I now work as a Clinical Data Coordinator who directs various teams of people in the running and management of data in a Clinical Trial of new drugs. The work I do every day helps very sick people live longer, and happier lives. The ability to think "outside the box" and see the big picture is what I appreciate most. Chemistry has remained a hobby of mine and my element collection brings me great pleasure.

It's good to hear that you appreciate pointers more than direct answers, because that is what we are more likely to give you. We don't WANT to assume that someone is just asking for answers and will never return again, but we see a LOT of that on a daily basis and it's frustrating. Remember; Teach a man to fish and he'll eat for the rest of his life. Give a man a fish and he'll eat for one day.

As the temperature decreases, so does the solubility of the components of the solution. (Typically speaking). As you cool that solution, the concentration of it changes. As this concentration changes, so does the freezing point of the solution, hence the issue you have experienced.

You just need to rebalance your equation, but otherwise it looks fine! You're just stating the procedure for producing trinitrobenzene. So just try and balance your equation and you'll be fine.

No it doesn't. If the breathalyzer says your BAC is 0.08, which is the legal limit in most states in the US, that's ground for arrest. There is no need for suspicion and they do NOT need a blood sample to prosecute you. There is also no way to "trick" a breathalyzer. The amount of EtOH that comes out of your breath is directly proportional to the amount in your blood. You can't alter that. If you give a result that appears off, then the officer can request that you provide a blood sample to verify it. (And refusal could be grounds for arrest). But if you did something to alter the results (e.g., swish with some mouthwash) the results would be insanely high. The test works on a chemical reaction in which more alcohol in the blood generates more electricity. As much as people, people who deserved to be thrown in jail, have tried to argue, no scientific evidence has come out stating that breathalyzers are incorrect and cannot accurately measure the values of alcohol in a guilty person's blood. The only exceptions they can come up with would require the driver to be in such poor conditions that they'd be in horrible, unable to drive, shape anyway.

Also keep in mind that as you increase the atomic number of the element, you increase the number of protons in the nucleus. All of the positive charge of an atom is located within the nucleus, while the negative charge is dispersed amongst the electrons outside of the nucleus. Since the positive charge is located inside the nucleus, an electron that is further away from the nucleus won't feel as much of a charge. It will be shielded from that pull by the negative charge of the electrons between it and the nucleus. (Positive always wants to be with negative). While both K and Na have one electron in their outer shell, that outer electron in K has 8 more electrons between it and its nucleus. Even though K's nucleus has more positive charge, those 8 electrons do a good job of blocking that charge from that lone outer electron. As a result, that lone outer electron for K is easier to pull off than the one outer electron of Na. (Because that electron in Na doesn't have as much of a "shield" between it and the nucleus). The final question I'll pose to you is what do you think is easier; grabbing 7 more electrons to get a full set of 8 outer electrons, or giving up just one to get a full outer shell?

You have to realize, however, that for every person who comes on here with legitimate questions and honest curiosity we get ten times as many people who don't want to learn a single thing and only want someone to do their homework for them. As a result, when we see a relatively new poster on these forums who asks a lot of questions that are typical homework questions and asks for/demands an immediate response, it typically reeks of the type of person who only want someone to do their homework and nothing else.

I'd like to see an example of this because a halogen cannot form nearly as many bonds as a carbon atom can, so I'd highly doubt it could replace carbon.

Just keep one thing in mind; Elements will always try and obtain a stable configuration of electrons. The closer an element is to having a full external shell of electrons, and the stronger it's attraction/repulsion to electrons are, the more reactive the element.

At work, I typically receive a bunch of these links to WebMD and stories about what is going on in the world of clinical research. This article today really caught my eye, probably because I myself am a Type I (Insulin-Dependent) Diabetic. It has long been believed that Type I Diabetes was an auto-immune malfunction where the body's immune system mistakingly saw Islet Cells as foreign substances and as a result destroyed them. This recent research being done on mice in Canada, however, may bring research in a new direction. Apparently, they found that a specific neurotransmitter was "different" in mice which had Type I Diabetes as compared to those without Diabetes. These chemicals are transmitted by specific neurons denoted as TRPV1 neurons. These diabetic mice had very weak chemical signals being transmitted by these neurons. They found that by altering the levels of these chemicals, the mice would in many cases become Diabetes Free! Of course they still need to do a lot more research on this, but if these findings are true it could mean a HUGE break in Diabetes research. I am hoping that they can find a correlation in humans as well. The funny thing with me is that I am the only one in my family lineage with Diabetes. NOBODY else in my family tree has the disease so the fact that I got it seems odd. My family does, however, have a great bevy of neurological disorders. It would then make quite a bit of sense if Diabetes develops due to a problem in the nervous system. I'm really hoping this is true as it would be incredible to make a discovery like this. EDIT: Sorry. Had to remove the link because it may have linked to my company's servers. The source of the story is; SOURCES: Razavi, R. Cell, Dec. 15, 2006; vol 127: pp 1123-1135. Bour-Jordan, H. and Bluestone, J. Cell, Dec. 15, 2006; vol 127: pp 1123-1135. News release, The Hospital for Sick Children.

Remember that the volume of a gas is directly related to the number of moles of the gas, and not what the actual gas is. Therefore, one mole of hydrogen gas at the same temperature and pressure of one mole of hydrogen selenide gas will take up EXACTLY the same amount of space. (Provided that both gases are acting as ideal gases). Your reaction looks pretty close, but make sure all the moles add up. The H2Se, Sn, and H2 are correct. So I'd double check the selenium in your equation.

The problem is that if you go too much too soon you'll confuse the living hell out of a LOT of people and cause many to hate the subject forever. As it is right now, who cares if some random bloke who will NEVER have a career or interest in chemistry is told just the simplifications. Those who truly need to know the reality will learn it, but they'll learn it at a pace that will allow them to fully grasp the concepts. Trying to teach people all about every aspect of bonding right from the get go is like teaching someone calculus at the same time you are teaching basic algebra. I just don't agree with it at all. It is far more dangerous for someone to be taught the complexities of many chemical concepts than it is to simplify it for them and ensure that they grasp them and use them properly.

I agree with encipher here. There is a VERY valid reason WHY they simplify things in high school chemistry. If they started out by teaching advanced level chemistry to high schoolers or beginners in college, NOBODY would understand it. NOBODY!!!!! An analogy to this is cooking. You can't just throw someone in a kitchen and tell them to make a fancy creme-broule. They need to be taught how to cook, how to use the ingredients, how to use their tools.

It's a good idea to keep the entire apparatus quite warm, and the only cool part should be where you want the I2 crystals to solidify.

Hey Woelen. I think that in this reaction you may also wind up with some NBr3 if your reaction conditions are just right. I'm pretty sure that you wind up with a mixed reaction of NH3 + 3Br2 => NBr3 + 3HBr. The HBr is then immediately neutralized by the NH3 to give you your NH4Br white smoke. Nitrogen tribromide is so unbelievable unstable that the low amounts you are using are probably resulting in it decomposing immediately without any ill effects. Still, I'd be very careful when doing this experiment.

This is pretty simple. The elements you'll have to deal with most often in "basic chemistry" are the following (Mind you these are not in ANY real order. Just the order they came into my head as I started thinking about common compounds that are used in basic chemistry.); Hydrogen - H Oxygen - O Carbon - C Sodium - Na Chlorine - Cl Potassium - K Nitrogen - N Sulfur - S Iodine - I Copper - Cu Silver - Ag Zinc - Zn Lead - Pb Mercury - Hg Bromine - Br Fluorine - F Iron - Fe Phosphorus - P Magnesium - Mg Calcium - Ca You could also probably remember the noble gases as well, but for now I think the list I provided will suit you well.

Correct. This will give you the mass of oxygen that the specified reaction conditions will generate. In conjunction with the reaction equation specified above, you'll then be able to figure out the number of moles of oxygen produced and from that the number of moles of KClO3 produced. Once you have the number of moles, the calculation of actual mass is pretty easy.

Yup. Iridium kind of proves that "rarity" doesn't exactly denote cost. Rhodium is multiple times more common than iridium, yet an ounce of Rh costs 10 times as much, if not more, than an ounce of Ir. (I have about 40 grams of Ir yet only 10 of Rh thanks to the insane price of Rh). Price of elements all comes down to a combination of rarity, and ease of extraction.

Iridium is the "rarest" of the stable elements on Earth, followed closely by osmium and rhodium.

No problem. Sorry for my little rant there. I always get quite edgy during Christmas for some reason.

NaOCl + H2O2 => O2 + H2O + NaCl. Remember, bleach is a solution of sodium hypochlorite so the counter ion is the free sodium ion.

Yes, and did you read my post at all????? The man-made elements DO NOT COUNT when you are talking about the "rarest" of elements. This is because in all actuality they DO NOT EXIST!!!!! They only exist because man has made one just to say that he has. It does not make it rare at all since if you really wanted one, all you would need to do is go and make some more. As a result, it is completely unlimited and as such it is not rare at all. When you get into a discussion about "rare elements" you can only include those that naturally occur on earth. Please read the entire thread before you go around stating things as facts.