Ionization

[JJM]

Just to put in my two cents, ionization is probably the incorrect term to use when an ionic solid is dissolved. As pgwenthold remarked, the solid was already "ionized". The dissolution of an ionic solid, say NaCl in water, is a chemical reaction. {snip}

No, it is a physical process. The salt goes from one state (ionic solid) to another (ionic solution). You can wax philosophical about this stuff; but, don't.

 

[anor277]

Many certainly are, e.g., ammonium chloride.

But a weak acid is not necessarily a salt. I suspect pgwenthold (who certainly does not need to study introductory chemistry) was referring to ionization of neutral acids (i.e. water, phosphoric acid, hydrogen chloride) into anions and cations (i.e. "ionization").

There is some confusion here about the term "ionization." We sometimes use it to describe loss or addition of an electron, sometimes to describe the separation of ions in solution.

Agreed on the first part. But as for the second, "ionization" describes charge separation upon reaction of a neutral molecule.

 

[anor277]

No, it is a physical process. The salt goes from one state (ionic solid) to another (ionic solution). You can wax philosophical about this stuff; but, don't.

[Waxing philosophical]......We'll have to disagree on this point then. Chemical change is characterized by the formation of new substances and the making and breaking of strong chemical bonds. To take the example we were discussing, in the first place (the solid) we have an infinite array of positive and negative ions, held in position by electrostatic attraction; upon dissolution in water, this array has been broken up (the energy supplied by the solvation of the ions), and we have a host of new, discrete chemical species, Na⁺_(aq) and Cl^-_(aq), which, as I explained before are coordination complexes with water as the ligand.

So, therefore, dissolution of NaCl in water (i) breaks strong chemical bonds, and (ii) results in the formation of new substances. By definition this is an example of chemical change. Of course I supplied my own definition of "chemical change" but any that you supply would necessarily be similar.

 

[Mojo]

I suspect that this might be a problem to your argument:

...and the making and breaking of strong chemical bonds.

 

[JJM]

But a weak acid is not necessarily a salt. I suspect pgwenthold (who certainly does not need to study introductory chemistry) was referring to ionization of neutral acids (i.e. water, phosphoric acid, hydrogen chloride) into anions and cations (i.e. "ionization").[?quote]Yes, and he made a blanket statement about "acids." Pgw gets confused, as do I.

{snip} But as for the second, "ionization" describes charge separation upon reaction of a neutral molecule.

You are mistaken.

 

[anor277]

I suspect that this might be a problem to your argument:

Really? The electrostatic bonds that hold the ions is place are chemical (the bonds broken); the ion dipole bonds that form between the ion and the solvent in the new species are likewise chemical. I don't see the problem.

 

[anor277]

But a weak acid is not necessarily a salt. I suspect pgwenthold (who certainly does not need to study introductory chemistry) was referring to ionization of neutral acids (i.e. water, phosphoric acid, hydrogen chloride) into anions and cations (i.e. "ionization").[?quote]Yes, and he made a blanket statement about "acids." Pgw gets confused, as do I.

You are mistaken.

Then please enlighten me. I can get as confused as anyone; should I do so, I would not appreciate gratuitous comments about my need to study introductory chemistry.

 

[JJM]

Anor277: "... and the making and breaking of strong chemical bonds."

I suspect that this might be a problem to your argument:

I suspect that's part of it, too.

 

[anor277]

Anor277: "... and the making and breaking of strong chemical bonds."
I suspect that's part of it, too.

Then again, please enlighten me. If you disagree with my argument please state the reasons.

 

[JJM]

{snip} No, you really need to study introductory chemistry, I can't provide a lesson in this format. {snip}

Then please enlighten me. I can get as confused as anyone; should I do so, I would not appreciate gratuitous comments about my need to study introductory chemistry.

What part of "I can't provide a lesson in this format" don't you understand? Sorry, maybe someone else can.

 

[pgwenthold]

Many certainly are, e.g., ammonium chloride.
There is some confusion here about the term "ionization." We sometimes use it to describe loss or addition of an electron, sometimes to describe the separation of ions in solution.

And it is very poor language if used in the latter sense. If I saw it in the paper I was reviewing, I would recommend the author to speak more precisely.

An ionic compound is not ionized when dissolved in solvent. The ions already exist.

 

[pgwenthold]

But a weak acid is not necessarily a salt.
I suspect pgwenthold (who certainly does not need to study introductory chemistry) was referring to ionization of neutral acids (i.e. water, phosphoric acid, hydrogen chloride) into anions and cations (i.e. "ionization").

That is why I talked about the covalently bonded HA as my weak acid. If you want to talk about Lewis acids, then it is more complicated. The extent of ionization of the ammonium ion changes, but that is via chemical reaction (proton transfer) with the solvent and NOT by dissolving. From a reaction standpoint (for water solvent), you have

NH4Cl(solid) --> NH4+(aq) + Cl-(aq)
NH4+(aq) + H2O(aq) <--> NH3(aq) + H3O+(aq)

The proton transfer step is the ionization process, not the dissolution. Now, if that is what you mean by ionization upon solution, then I won't quibble, but it is far more subtle than (and, to the same level, we could say the same about covalent weak acids - they aren't technically ionized when dissolved, either).

This is very different from the initial implication that ions are created when salts (including NaCl) are dissolved in solvent.

As for not having to take intro to chem, I could, I guess, but I am too busy teaching graduate level chem courses right now.

 

[Eos of the Eons]

Okay, another question. We have two iron rods in this thing, from what I've been able to discover in the research.

Once the electrical current starts, or even before (I'm thinking not before), you end up with an anode and a chathode. Is this a random thing, or is it determined by which is hooked up to the the electricity coming in and which is hooked up to the electricity going out?

I'm thinking there is somewhat of a closed system for the current to keep the feet from being shocked. I'm looking for a picture of the innards of one of these machines.

 

[Eos of the Eons]

Just a side note, as it's been a long time since I took biology and chemistry, but don't forget that we're basically big bags of aqueous buffered ions in exquisite balance that is difficult to alter. Sticking ones appendages in salty water with a bit of an electric current in it will hardly do anything to the balance of or types of elements and compounds in one's body.

Yes, thank goodness, or we'd leak stuff out every time we took a bath. We'd leak different things depending on what we added to the water-salt, baking soda, bubble bath. At least we don't actually have to worry about it in reality.

I think I will use these kinds of points in the conclusion, thank you

Second, in general ions in solution do not create a magnetic field because their motions are isotropic (i.e. they are moving in all directions) and there are both positive and negative ions moving, so there is no net magnetic field. Moving unipolar ions do indeed create a magnetic field (just like a current does), but you are only going to find that in specific cases, .e.g. mass spectrometry. They will, however, respond to a magnetic field, as well as responding to electric fields.

This was another piece of the puzzle that I needed for this. Thank you P

man, if I get a coherent article out of this, I owe you all.

 

[Madalch]

Chemical change is characterized by the formation of new substances and the making and breaking of strong chemical bonds. To take the example we were discussing, in the first place (the solid) we have an infinite array of positive and negative ions, held in position by electrostatic attraction; upon dissolution in water, this array has been broken up....

Electrostatic attractions can hardly be considered strong chemical bonds.

 

[JJM]

Okay, another question. We have two iron rods in this thing, from what I've been able to discover in the research.

Once the electrical current starts, or even before (I'm thinking not before), you end up with an anode and a chathode. Is this a random thing, or is it determined by which is hooked up to the the electricity coming in and which is hooked up to the electricity going out?

The electricity coming out of the wall changes direction 60 times per second (alternating current). If you use it, the bars will alternate between being anode and cathode at that rate.

If I recall your OP, the device has a DC (direct current) power supply. In that case, one bar is the anode (positively charged) and the other is the cathode (where the electrons enter the salt water).

I'm thinking there is somewhat of a closed system for the current to keep the feet from being shocked. I'm looking for a picture of the innards of one of these machines.

There are two things (at least) that prevent you from receiving a shock. First is that the power supply only provides a low voltage which is insufficient to affect you that way. Second, your body (skin) is pretty resistant to electrical current, whereas the salt solution is more conductive- the electricity follows the path of least resistance.

 

[Madalch]

Okay, another question. We have two iron rods in this thing, from what I've been able to discover in the research.

Once the electrical current starts, or even before (I'm thinking not before), you end up with an anode and a chathode. Is this a random thing, or is it determined by which is hooked up to the the electricity coming in and which is hooked up to the electricity going out?

It's determined by which end of the battery it's hooked up to. The negative terminal will provide electrons, which will cause reduction (making it the cathode); the positive terminal will remove electrons, causing oxidation (making it the anode).

 

[Eos of the Eons]

yes, it's

Two iron electrodes have a low voltage/amperage AC to DC transformer connecting them.

Does that mean it's run on batteries... or can you plug it in. heh, I don't have much of an electronics background either. I'm just going to say "when you turn the machine on" without having to worry about the small detail of whether or not you just replace the batteries or plug it in anyways.

That's it, next time I'm sticking to purely biology topics. argh! My paragraph on why heavy metals can't move through skin via osmosis is the only one I won't need help on

But it will be a good article, I'm sure, with all the help. Sigh. It's looking good, just one more paragraph to clarify.

 

[JJM]

Does that mean it's run on batteries... or can you plug it in. heh, I don't have much of an electronics background either.

That's it, next time I'm sticking to purely biology topics. argh! My paragraph on why heavy metals can't move through skin via osmosis is the only one I won't need help on

An "AC to DC transformer" means it is run on house current (plug it in).

 

[Eos of the Eons]

An "AC to DC transformer" means it is run on house current (plug it in).

Thank you *feels silly*