raivo

Mostly carbon, oxygen, hydrogen and nitrogen.

It is possible to have anhydrous sulfuric acid but it can not be made by evaporation. There are other ways ( such as saturating with SO3 gas )

Come on people' date=' lets think of something large scale to do. The key here is I have lots of this stuff and while these demos are cool, they're small. Whats something that is only effective to do with large amounts of acid or much more effective when large amounts are used.

 

~Scott[/quote']

 

You can use remarkable amounts of (concentrated) sulfuric acid if you will make remarkable quantity of nitric or hydrochloric acid or organic esters.

 

When boiling acids you have to use boiling stones (some pieces of broken porcelainware) otherwise it does not stay in the flask!

If i were you i just boiled it to high conc. Then i would get aproximately 1l concentrated sulfuric acid. Thats not too big amount to store and diluted sulfuric acid has not much use anyway.

Bad:

H2S,

polyamide decomposition products,

nitrogen oxides

Good:

not easy to tell because all smells we know frome everyday life are due of some chemicals. There are lot of smells that are good if not too strong and bad if conc of fumes is high. HCl for example. Generally i do not like smells of chemicals but various essencial oils smell trully good.

You do not need to mantain 12V. If you can lower impedance of your electrolyser you get as much ( or even more current ) using lower voltages. Amount of hydrogen produced is directly proportional to current. Voltage in itself does not count. Voltage is just for increasing or decreasing current.

Current can be computed by Ohms law. I = U / R where I is current, U voltage of your power supply and R impedance of electrolyser.

Amount of hydrogen produced depends only of current (that Faradys law), no matter what voltage was needed to generate that current. To increase current you need to lower impedance or to rise voltage. By rising voltage you get heating problems so you need to lover impedance of electrolyser. This can be made by using more concentrated electrolyte and/or more electrode surface.

Industrial electrolysers work usually with voltages as low as 3...4V. Still they get currents of 1000 -s of ampers because electrodes have great surface area and electrolytes are well chosen.

Amount of power is proportional to current and voltage. If you electrolyser uses 5A current ( for example ) then power consumption is 15W if voltage at electrodes is 3V, and 60W if voltage is 12V. In both cases electrolysis goes with same intensity, ( depends only of current ) but power consumption is very different. That excess power goes for heating.

Electrolyser has to have very low electrical impedance - otherwise it requires high voltages to get reasonable currents. High voltage & high current means heating problems.

Impossible to tell. Even very diluted sulfuric acid will react with iron. You do not need burettes or anything to measure conc in your home lab. Any graduated cylinder or pippete gives acceptable precision.

You just need to know how much alkali is needed to neutralize known amount of your acid. Thats easy and there is no other way.

One more idea: you can collect all hydrogen from your experiment and compute amount of sulfuric acid by hydrogen volume.

Thankfully, however, like many toxic gases the human nose is so sensitive towards the smell that concentrations faaaaaaaaaar below a toxic or lethal amount can easily be detected. (Same is true for the halogens, hydrogen sulfide, and many arsenic compounds). You just have to be careful that you don't overwhelm/numb your scent receptors. That could be bad.

Its true that human nose will sense most gases far below lethal conc but there are some gases that feel almost the same no matter if conc is lethal or just 1/4 of it. H2S is one of such. It is one of nastiest substance to work with.

As a side note' date=' anyone who recommended sulfuric acid should be shot. It produces hydrogen sulfide gas when it electrolyzes. [/quote']

 

Sulfuric acid electrolysis will never release H2S (expect in case you use sulfides as material for electrodes or container). Sulfuric acid is quite common for water electrolysis, only minus being stability of anode. Thats why NaOH is preferred.

 

When using VERY strong currents with H2SO4 you may get some gaseous sulfur oxides and peroxyacids as byproducts but no H2S.

I agree with coquina. Al is usually anodized or plated someway and if it loses that finish it can not be easily restored. Atempts to chemical etch or polish aluminium tend to make it just more ugly.

Resistance decreases with heating and rust will not affect it much. If you use NaHCO3 as electrolyte you cant get very low resistance. Its good idea to heat this salt on hotplate half on hour so it decomposes to Na2CO3. Na2CO3 is more soluble and has lower resistance. NaOH is still better. You could also use H2SO4 but electrodes will be a problem.

Multimeter is great help but you have to check what are max currents it can measure. Stronger currents can destroy it.

Just a little side note. Even though the PSU I'm using can supply 25A at 5V and 10A at 12V, and 0.8A at -12V and everyone has said that current matters most, using the 12V and -12V leads gives the best results.

Current depends on resistance and voltage (according to Ohms law). You have to lower resistance or increase voltege to get more current. 25A at 5V will flow through electrolyte if resistance is as low as 0.2 ohm. Resistance in your apparatus is probably much higher. If it is 100 ohms for example you get just 0.05A current when using 5V, and 0.24A when using +12V and -12V. -12V rail cant supply more than 0.5A. Something like that is probably max current you have got so far.

Does anyone know how hot some glass, say a jam jar for example can get before it cracks?

If you heat it slowly with hot air so that temperature difference will never exceed 50C in any part of jam jar then it does not crack, just starts to soften at 400C or maybe 500C. Common glass cracks if temperature difference between nearby points is at least 80C ... 120C. Temperature in itself does not count, just difference.

If you are lucky acetone may work, xylene or white spirit are more realistic. There are still lot of plastics that can not be properly liquified with easyli available solvents. Really strong solvents for plastics are dichlorometane, acetonitrile, chloroform or molten phenol.

Chemical element has to have certain quantity of protons in atom. If it has more or less its another element. Atom contains also some neutrons but if it has more or less of them then its still the same element but different isotope. Isotopes are as common in nature as usual elements. (which are just most common isotopes or mixtures of them)

Less common isotopes can be collected and concentrated or made artifically by nuclear reactions

To: Bud

I am sure you do not intend to break laws or do anything bad but do not expect everyone will belive just your words. Todays world is very paranoid about drugs. Geting unfriendly attention by parents, neighbours or police IS serious labwork danger!

For your original question: use what you can buy from pharmacies and do not modify it or if you want to extract or alter something be sure you are far enough from illegal stuff.

What you want to do is not completely safe and if some very special idiot will know of you, you may get into (hopefully minor) trouble. You do not need to do anything illegal to get special attention of authorities. They have right to investigate. If you are not ready for this, then better do not do any reactions with nearly illegal drugs. Only test them as you bought them from legal supply not doing any conversions yourself.

Hoffman apparatus is classic device to explore water electrolysis.

I want this thing to convert a Gallon of water into H2 ande O2 every 25-30 minutes. I know that will take alot of units, but if each is as perfect as possible it might just work.

This is completely unrealistic. To decompose 1 mole (18g) in 30 minutes you need more than 50A current. To decompose 1 gallon you need more than 10 000 A.

Most of your questions can not be answered remotely. You have to do some experimenting and computing to be successfull. Do similar electrolysis in small flask several times with different setup and measure anything you need to know. Do not expect anyone can just tell you everything.

1..2cm is probably not enough 5...7cm is more realistic but you have to test this some way because this depends on several factors, such as liquid movements on working electrolyser. 10% NaOH solution may be good choice, chemical stability of NaOH is generally very high but this also depends on many factros, such as exact composition of electrode material or various contaminants that find way into your electrolyser. If you want to succeed, you have to do lot of experimenting, all that can be easily explained has already been explained here.

Buy some cheap drain cleaner that does not contain hypochlorite ( most of these are just solution of NaOH ) or ask someone who makes soap at home or boil solution of Na2CO3 together with lime.

12A is enough but as jdurg said there is much more problems to solve. Even melting NaCl and holding it liquid during 5 min is not easyest thing.

How about I don't mix them until the moment they have to ignite? I could just have four lines come up in a cross formation, two H2 and two O2, they will discharge next to eachother and at an upwards angle. This will make the H2 and O2 mix in the air, not in some tube. (too lazy to draw a MS Pain pic. use your imaginations)

It would be perfectly safe if your hydrogen is not contaminated by O2 inside of electrolyser.

Separate lines makes it safe only if pressures in both lines are equal or if gases are mixed outside the burner. Most easy and safe way would be to generate just hydrogen and use it in something similar to bunsen burner.

Power bills would not to be that shocking. 5A of current through electrolyte should give you small stable flame. If you use 12V this needs just 60W, if 5V then 25W.

All right what Lance said. Ground is usually black (two central contacts in floppy disk connectors) +5V is usually red. +12V is usually yellow. If PSU is old enough ( from AT type computer ) then it does not need any additional connections. If it was used for Pentium motherboards it may need some more connections to switch on.

I have found that AT type power supplyes are most reliable for lab use. They cant be ruined by short circuits. Some newer power supplyes can be easily ruined.