jdurg

Yup.

Cool. Now you don't need to be taking LSD to hear a visual event!

Exactly. Let's take a look at how the interpretations could be different. Let's say you have a solution that's 37% HCl w/v. As the density of 37% HCl is about 1.19 g/mL, a 37% w/v designation means that in 1.00 Liters of solution you will have a total mass of HCl of 440.3 grams. That's equal to about 12.06 moles making your molarity 12.06 Molar. Now if the designation was 37% w/w, that means that in 100 grams of solution we have 37 grams of HCl. With this information we could figure out the molality of the solution then convert it to molarity. 37 grams of HCl is about 1.014 moles. So we take 1.014 and divide it by the kg of solvent (water) which would be 0.063 kilograms. This gives us a MolALity of 16.095. Now we can convert that readily to molARity and we get a value of about 12.07 molAR. So while the difference isn't much, there is a difference which could affect any volume precise experiments you are doing. (BTW, chemicals such as acids and bases are typically denoted in the w/w %).

My bad. I always get those two switched and forget the simple phrase 'An Ox, Red Cat'. Reduction is at the cathode and oxidation is at the anode. Let me go and edit that post..... Heh. Too late. Can't edit.

Yes, liquid helium shows virtually no effects of friction. However, helium is only a liquid a few degrees above absolute zero (-273 C, or about -459 degrees Fahrenheit). (BTW, while this sounds very nit-picky and anal-retentive, please try to fully spell out your words when you type. When people see posts filled with 'wat' instead of 'what', 'fo' instead of 'for', 'wit' instead of 'with', or various other slang terms they are less likely to take your posts seriously and much less likely to respond to them. I'm just stating that to help you out here. )

It will say it someplace on the bottle as in w/w or w/v. w/v means that in one liter of solution, 31.45% of the weight is from HCl and other 68.55% of the weight is from water. If it states w/w, then it means for every 100 grams of solution, 31.45 grams are HCl.

Yes, but in the chamber with the copper hydrogen gas would form. That would leave you with Na+ and OH- ions in solution. Copper would then go into solution to balance the charges. No matter how hard you try, OH- will exist in solution. Otherwise it would be impossible for the Hydrogen gas to form. @jowrose: From what I understand, xeluc was using two separate container connected with a salt bridge. The copper anode was in one beaker with an NaCl solution, and the cathode was in the other beaker. As the current is applied, H2O is reduced to OH- and H2 at the anode and at the cathode Cl- is initially oxidized to Cl2. Ions move along the salt bridge to help maintain a balance of charges. The reason Cl2 is produced initially is because of a concept called overvoltage. If you do a search on google you'll be able to find a nice explanation about it. Basically, initially it is more favorable for the Cl- to be oxidized to Cl2 than it is for the OH- ions in solution to be oxidized to oxygen gas.

Various amounts of sulfur oxides exist in the air normally. While petrol formulations do add to this sulfur content in air, there is a great deal of it that normally exists in cities. In reality, the sulfur isn't the biggest problem one faces. It's the nitrogen oxides and those you cannot avoid. Even if you are combusting hydrogen and oxygen together, the high temperatures and high pressures resulting from that combustion will result in the formation of nitrogen oxides. It's something that you just can't avoid. The higher the pressure and/or the higher the temperature, the more likely it is for nitrogen and oxygen to react. The optimal combustion would occur at a lower temperature and a lower pressure in order to avoid the formation of any unwanted NOx's.

Well for me it was easy because I never really asked for anything, nor did I really "want" anything. I guess I've just grown out of Christmas.

For Christmas I got a gift card to BestBuy which will be good for a couple of movies, a complete set of 2005 Topps Baseball Cards (I have a complete set of these from the year I was born through the present year. 25 years of cards is a LOT of cards), a few shirts, a series of Golf Lessons for next spring, and a check which has helped finance the purchase of a one-ounce 24-Karat Gold Maple Leaf coin.

The electrolysis of an NaCl solution produces chlorine gas and sodium hydroxide. As the copper metal corrodes away, the copper ions will react with the free OH- ions forming Cu(OH)2 which will ppt out of solution.

That would be your best bet and would also provide pretty conclusive proof that you are generating CO2 gas.

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.

Nickel metal is a common additive to iron to increase its workability and durability. The fact that you are seeing a greenish solution makes me think that there may be some nickel in there.

As long as you can prove to Harvard, or any school for that matter, that you can make money for them they'll accept you. Grades truly are overrated, as are test scores. If you have the money, any school will accept you. The thought that 'I'm special because school such-and-such accepted me' is the biggest farce of all. You don't need to be "special" to be accepted by a school. You just have to prove to the school that you could possibly be a source of finances for them. This is what a school looks at when accepting students: 1) Can this student pay us the money that we are asking from them? 2) If he/she cannot, is there a good chance that the student will be able to succeed in his/her field and provide donations to us later on? If so, we'll give him/her a scholarship. 3) If this student isn't the greatest of our applicant pool, will they at least be able to pay us what we're asking for and graduate while providing us with donations later on? 4): Is this a smart student who will get things done and improve our standing in regards to financial acquisitions? EVERYTHING the colleges out there do is for money, not prestige or anything else. When a school accepts an applicant, they do so thinking about the money they can make. If you are a student who has the drive and show a school that you can suceed there you will be accepted anywhere you want to go. When applying for college later on in life chemfreak, remember that getting rejected from a "higher learning instituation" doesn't mean that you aren't a good student. It most likely means that the school felt as though you couldn't make money for them. On the opposite side, if you get accepted by a "higher class institution" it doesn't mean your better than anybody else or that you know more than other people. It simply means that the school thought you could make them some money.

Bingo. Nobody gives a crap about an undergrad degree. All it shows is how much money you were able to spend. It's the graduate degrees that people tend to take notice of.

Water is not used in a fire extingusiher, and when CO2 is used it is used under a great deal of pressure. Read through the thread and you'll see that the decompression of a compressed gas results in a significant drop in temperature.

However of all of those, silver nitrate is the least of your worries in terms of 'toxicity'. AgNO3 is still used to chemically cauterize small wounds while disinfecting at the same time.

I would guess that the carbon is disintegrating and immediately reacting with the oxygen produced to form CO2. With a very large surface area, it's quite possible that this is what is happening.

But if you have the inert gas and the proper apparatus, which the original poster most likely does not, then what's the point of using the mercury cathode when electrolysis on a molten salt would be just as easy. In addition, those who would like to make sodium metal probably don't have pure calcium or lithium metal hanging around. (Because if they could get pure Ca or Li, they could easily get Na too).

Yes, please do not use normal glass containers. When I did my sodium + iodine experiment to make NaI, I used a normal glass jar for the reaction chamber, and within a few seconds of heating it cracked spilling liquid iodine and a mass of sodium all over the place. It was a nasty mess to clean up.

Yeah, but now try and get your sodium out of your mercury without losing it all to instant oxidation.