1)Where do they get all the chlorine needed for swimming pools, laundering needs, and to go with polyvinyl for the necessary polyvinylchloride in our telephones and electrical equipment, and many other uses of this element?
2)Years ago my high school chemistry teacher brought in a little strip of one of those early metals in the Periodic
Table, like potassium or sodium, and it was in a vacuum. When he let air get in, the strip flamed up and he commented
that what we call burning is merely rapid oxidation. This metal can’t exist by itself but is always combined with something. What if he had let in chlorine gas instead of regular air with oxygen in in, would little crystals of salt have formed instead?
3)Why do they list on every product containing salt how many milligrams of sodium are in it? May we not infer from this omission of the chlorine that the human body actually separates out the chlorine and the sodium? Then we would be filled with a poison gas and an explosive metal flying around in us!
4) I read in a science fiction book about these space travellers who landed on a strange planet where blocks of iodine were floating about in pools of bromine. Iodine is a solid and bromine is the only element besides mercury that I have heard of that exists in liquid form at our temperature and pressure. But can blocks of iodine exist or pools of bromine, and what would happen if they got together? (The planet was just like earth in pressure, atmosphere, gravity, etc.)
By way of general explanation you need to be aware of the difference between chlorine, bromine, etc. atoms and their ionic forms. The atoms are highly reactive substances because of unfilled valences – the ions, although no longer electrically neutral, are much less reactive. For example, salt water (as in the ocean, or your bloodstream) is filled with sodium ions and chlorine ions. These ions take part in numerous chemical reactions all the time, but they neither catch fire or poison us.
Answering your questions:
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There are a lot of minerals with cholrine atoms. The most common, as you are well aware, is sodium chloride, common salt. You can get other chlorine compounds, as used in swimming pools and bleach, starting from salt. I don’t know what the actual process is, or whether they really start with salt, but a shortage of chlorine atoms is not a problem.
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Essentially yes.
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There are other sodium sources in foods besides salt, although salt usually dominates. For instance, the sweeteners in diet soft drinks are sometimes made from sodium compounds so your Diet-Rite Cola has sodium in it but very little salt. For the presence of poison gas and explosive metal, see the opening paragraph.
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Yes, pools of bromine and blocks of iodine can exist. The reason don’t see them is that they are, like chlorine, highly reactive and would never exist in their elemental state in large quantities. The author of your story was misleading (or you misunderstood) that the atmosphere of the planet would be just like earth’s. It would require a special environment to prevent those elements from combining with their surroundings.
This Britannica.com entry has more information on the manufacturing of commercial quantities of chlorine (and the other halogens).
You can find answers to the rest of your chlorine questions by doing a Britannica search using the terms “chlorine manufacturing”
- Whenever you dissolve NaCl in water the sodium and chloride ions seperate. But, as pluto explained, they are not in their unstable, neutral form. They exist as ions, which is what form they take as a result of the nasty reactions their neutral forms undergo. Much of their chemical energy is used up. Alhough they have a formal charge in their ionic state, the polar nature of water can stablize the charge.
Says who?
I’ve seen iodine crystals before. Heck, I’ve even held them. They stain your hands orange.
Regards,
Psychonaut
http://www.nothingisreal.com/
I’ve seen them, too. And bromine. It doesn’t invalidate the gist of the answer to the OP which was that elemental bromine or iodine is unlikely to be found in a natural environment in any large quantities.
To supplement the answer to 3), http://www.webelements.com, in addition to may other interesting pieces of information, provides information on the amount of the various elements present in the human body - chlorine is present in the amount of 1200000 parts per billion by weight. Sodium is present in 1400000 ppb. Given the atomic weights of Na and Cl (about 23 and 34, respectively), that suggests that even if ALL the chlorine were present in the form of NaCl, there’s quite a bit of leftover sodium in the form of other compounds, and some of the chlorine would be from the hydrochloric acid in your gastric juices. I’m mildly surprised - I would have guessed that the numbers would have been about 3 to 2 chlorine to sodium by weight, almost entirely accounted for by salt.
And of course, astatine is a halide, too. Now, THAT’s one I’ve never seen close up, thankfully. I read somewhere that at any given moment, about 2 Kg of astatine exists on the entire Earth (it’s highly radioactive, with a half life of about 8 hours for the most stable isotope).
My grandfather was a chemist, and had a dog named he named “NaCl”, pronounced “nakel”, “nake” for short.
Let’s not bicker, but I must inform y’all that sodium always exists in its ionic form in the human body, and whenever we injest that, we are injesting an alkali salt yes, MSG, NaCl… those are all salts… so technically all sodium we get is from salt. Unless you’re eating metalic sodium, which would instantly explode in your mouth when it reacted with the water in your saliva, sodium is injested in a salt. The reason sodium is so important is because its a highly regulatory ion and involved in a lot of our regulatory processes (including processes that maintain blood pressure). Too much or too little sodium is dangerous. We need a relatively large amount of sodium in order to survive (compared to other nutriets such as Selenium which is sold at health food stores as a cure-all in such exceedingly small doses that it’s virtually undetectable in the pills). The problem is we now eat way to much of the stuff, causing our sodium pumps to go out of wack. Chloride is one of those ions that’s not nearly as important… so no one watches their chloride intake. Though, if you want to, you could probably demand to know what it is.
It is easy to figure out how much sodium is in a gram of pur NaCl (note however that table salt is rarely, if ever, pure NaCl). Just look at the periodic table for the atomic masses, make a nifty proportion and multiply. The amount of sodium ION is what matters to the human body, not the chloride ion so much.
Now about liquids and solids. Iodine in a bromine sea would indeed be possible in an earth-like atmosphere. Electrochemically, kinetically, and thermodynamically, we just need to make sure that there is no other substance that will reduce the over-all energy of the system (delta G, for all those who remember some college Chemistry). What’s important to realize is that in order to have a BROMINE sea, we need a particular temperature and pressure for the liquid to be stable. It so happens that our 101.3 kPa and 20 degrees C atmosphere is just about right for bromine. The problem would arise, on earth at least, that the Br and the I would likely react with some of the more metalic elements in our earth’s surface. However, nitrogen, oxygen, carbon dioxide, and argon (our major components of our atmosphere) will not cause problems for our halogen friends without extenuating circumstances.
- That’d be potassium or phosphorus, I can’t remember which. Sodium and the other one of the above pair react violently with water. Rapid oxidation, indeed. It also releases the hydrogen form the water, and is an exothermic reaction. If there’s more than just a teeny little bit of sodium, it gets hot enough to ignite the H[sub]2[/sub], which burns very fast (i.e., BOOM!).
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True story, happened when my chemistry teacher was in grad school: coupla students were cleaning out the lab, found a big block o’ sodium. Took it out back, and threw a few 5 gallon buckets of water on it.
The fireball went higher than the window of the third-story lab my teacher was in. The idiots that did it got a severe chewing-out from the administration as soon as they recovered their hearing.
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Oh, and the chem teacher also showed us pure iodine crystals. It’s really dark purple. Only the oxidized compounds are orange.
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[sub]kinda continuing Gunslinger’s hijack[/sub]All of the alkali metals - lithium, sodium, potassium, rubidium, cesium and francium - will have that kind of violent reaction with water. The reactions get more violent as the size of the metal atoms increases. On the other hand, the smaller halogen atoms (like fluorine and chlorine) react more violently than the larger ones (bromine, iodine and astatine)
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[sub]more of a hijack than my previous point[/sub] It depends on your definition of ‘our temperature and pressure’, but gallium and francium are considered to be liquids on some periodic tables. They have melting points at around 27 - 30 degrees Celsius.
didn’t you do the electrolysis of salt water at school?
you end up with chlorine gas and sodium metal when you pass a current through the solution. but it’s expensive, and i think the commercial process involves hydrogen chloride in some way.
The encyclopedia reference someone mentioned first says that bromine is a fuming dark red liquid, and later on it says it can’t exist (as such) in our conditions. Qui vide. Thanks to all, on this very interesting subject. Although I neveer could understand the part about solutions making subsstances like sodium chloride disassociate into “ions.” Isn
t an ion just some element that is missing an electron orhas an extra one, in which case A) does it have, if there is a bunch of these ions I mean, the same qualities as if the aggregate was a bunch of atoms of the element?, and B) by definition wouldn’t an ion be unable to exist at all, since it would want to combine right away? Or is the answer that an ion of chlorine consists of like two chlorine atoms and would thus be a molecule?
An ion of chlorine is one chlorine nucleus (17 protons) with 18 electrons around it. Because of the charge, you’re not likely to see a bunch of them together, all by their lonesomes, but they’re perfectly stable, as long as they’re in the vicinity of a like number of positive ions (as with table salt dissolved in water, for instance).
No, the properties of the ion are very different from the properties of the neutral atom. Table salt is quite different from chlorine gas or sodium metal.
Some elements prefer to be ions rather than in a molecule.
No, two chloride ions would try to stay as far apart as possible since like charges repel.
Doing such a bizarre experiment would result in some interesting products, but certainly NOT chlorine gas and sodium metal… That’s because both of these molecules (and Sodium ESPECIALLY) will react with the water. Attempting to tack on an extra electron just won’t work. In fact, if you electrolysize water, you end up with Hydrogen and Oxygen Gas… I assume if there is some chloride you’ll end up with Sodium Hydroxide (base) and Hydrogen Chloride Gas along with the hydrogen and oxygen products as well… You’d need to bubble off all the hydrogens, oxygens, and chlorines in gas form before you’ll get sodium metal. By that time, you’re basically dealing with supersaturated solution, I’d imagine. Any chemists care to elaborate?
Not that bizarre, though you’re right, it doesn’t produce sodium metal -
That Brittanica article somebody linked says that the standard commercial process for chlorine production is electrolysis of brine, producing sodium hydroxide (that’s where the hydrogen and oxygen produced from the water go - with some hydrogen left over) and free chlorine. The article seems quite good.
To confirm from http://www.webelements.com:
I imagine the chlor-alkali process described is cost effective because both the chlorine gas and sodium hydroxide resulting are useful industrial chemicals.