Oh Noes! Not Dihydrogen Monoxide! - Page 3

Urban Ranger · March 16, 2004, 02:00

Quote:

Originally posted by Kucinich
CaO isn't a molecule. Molecules are formed with COVALENT bonds only.

That is so wrong I can't even tell you how wrong you are.

Kuciwalker · March 16, 2004, 02:01

Hmmm, my textbook and my teacher say it is correct. UR, who has no chemistry credentials that I know of, says "it's wrong". Who do you think I should trust?

Urban Ranger · March 16, 2004, 02:03

Quote:

In chemistry, the molecule is the smallest indivisible portion of a pure compound that retains a set of unique chemical and physical properties.

Check the link in my previous post.

What do you call CaO? A couple of atoms just love to huddle together?

Kuciwalker · March 16, 2004, 02:05

An ion.

Theben · March 16, 2004, 02:11

ions can be molecules or atoms. They just have a + or - charge.

Ogie Oglethorpe · March 16, 2004, 02:18

Kucinich,

CaO - Calcium Oxide is definitely a molecule. The fact that it is an ionic bonded molecule has no bearing other than to describe the type of molecule it is.

If you are inferring that b/c it is ionically bonded it can form ions in dyhydrogen monoxide, that may be true but has no bearing on the fact that this particular salt is indeed a molecule.

If your teacher has issue with this have him or her give me a shout. I think perhaps somethingisgettinglost in translation.

Combat Ingrid · March 16, 2004, 02:41

Salts are not molecules. A molecule is defined by having covalent bonds.

Ogie Oglethorpe · March 16, 2004, 03:00

CI,

Since when?

Salts most definitely are molecules. Do a simple search on Ionically bonded molecules.

Matter of fact there is a whole branch of chemistry associated with Inorganic Chemistry that speaks to molecules not having covalent bonds.

Believe me I've been doing this stuff 17 + years.

Combat Ingrid · March 16, 2004, 05:03

From what I have learned salts are not molecules. A good example of the difference is to compare NaCl (a salt) with sucrose (a molecule). If you dissolve sucrose in water, you will get sucrose molecules dissolved in water. When you dissolve NaCl, you will not get dissolved NaCl molecules, but rather their ionic components dissolved in water.

However, I guess that compounds with stronger ionic bonds may be regarded as molecules. There's probably a grey area where you could define a given compound as both a "salt" or as a "molecule", depending on your taste

If you have been doing science for a long time, I assume you too know that one should be very careful with phrases like "most definitely"

Ogie Oglethorpe · March 16, 2004, 09:16

CI,

The property of dissociation of ionically bonded molecules in dihydogen monoxide does not change the fact that there are three forms of molecular bonding.

Ionic, covalent, and polar covalent bonding. (Most folk do not recognize hydrogen bonding a chemical bond but some add that one in as a fourth).

SpencerH · March 16, 2004, 09:46

CaO calcium oxide
CO carbon monoxide

Traditional nomenclature varies

Molecules do not have to be covalently bonded; consider the case of multimeric enzymes.

Combat Ingrid · March 16, 2004, 10:23

But they are separate molecules held together by various non-covalent interactions.
Or do you suggest that the lipid bilayer (the cell membrane) is one single molecule?

I don't really want to discuss this further, it's all just a matter of definitions anyway. Since definitions are made by people they will never fully comply with reality

-Jrabbit · March 16, 2004, 10:54

Nice threadjack!!

MrBaggins · March 16, 2004, 11:02

Oh no! The sky is falling! The sky is falling!

or... at the very least solid Dihydrogen Monoxide crystals.

SpencerH · March 16, 2004, 12:03

Quote:

Originally posted by Combat Ingrid
But they are separate molecules held together by various non-covalent interactions.
Or do you suggest that the lipid bilayer (the cell membrane) is one single molecule?

I don't really want to discuss this further, it's all just a matter of definitions anyway. Since definitions are made by people they will never fully comply with reality

It is just a matter of definitions. Multimeric enzymes are called 'molecules' despite their being made up of smaller non-covalently linked molecules.

Dr. A. Cula · March 16, 2004, 12:14

This story reminds me of an actual prank played by a local TV station some years ago. they went to the entrance of the Parliament building and asked one question of all senators they saw: "Do you feel it is correct that water should contain 66% hydrogen?" With one exception, everybody else was outraged by this fact, and some even promised to propose a law to correct this situation. Which they did! Of course, the TV station revealed the prank the next day, so the law was never passed, but still...

BTW, what is the actual percentage of hydrogen in water? I seem to remember from high school that it was something else.

Solomwi · March 16, 2004, 12:31

Quote:

Originally posted by Dr. A. Cula
BTW, what is the actual percentage of hydrogen in water? I seem to remember from high school that it was something else.

It depends on what percentage you want. It's true that 66.7% of atoms in water are hydrogen, but it only makes up about 11% by weight, IIRC (2/18). I may be a few years removed from 10th grade chemistry, but this is the first I've ever heard of ionic bonding not forming molecules. Also, IIRC, sucrose dissolves in water by hydrogen dissociation, but my memory could be rusty.

Dr. A. Cula · March 16, 2004, 12:38

Yes, I was thinking in terms of weight. Thanks.

bipolarbear · March 16, 2004, 12:46

Anybody know how much of the other crap( lead, arsenic, etc.) is in our water on average?

MrBaggins · March 16, 2004, 13:00

Quote:

Originally posted by bipolarbear
Anybody know how much of the other crap( lead, arsenic, etc.) is in our water on average?

Depends on how many peoples kidneys its been passed through prior to your drinking it

Provost Harrison · March 16, 2004, 14:38

Quote:

Originally posted by Azazel
I am an undergraduate chemistry student, and I don't remember it. Hydrogen Oxide is the correct name, IIRC, due to oxidation levels.

Why not hydrogen hydroxide?

centrifuge · March 16, 2004, 15:14

Quote:

Originally posted by Kucinich

Hmmm, according to my chem teacher it's monoxide. According to him, all molecules use the mono- prefix, and since oxygen-hydrogen is covalent it's a molecule.

This is killing me

I'm a chemist, and I can comfortably tell you that covalent bonding does not define a molecule (

Ogie). The definition of a molecule is simply when more than one atom is connected together. This means that H2O is a molecule, NaCl, is a molecule, and H2 is a molecule. O, Na, Cl, and H, are atoms. The type of molecule that they are generally is classified by how they bond.

When it comes to nomenclature, dihydrogen monoxide is a perfectly fine way of naming it. The nomenclature rules depend upon the type of molecule that you have (ionic, covalent etc). When naming an ionic compound (generally identified because they contain a metal and a non metal) you state the root name of the cation followed by the name of the anion. for example NaCl = sodium chloride, Cu2O = Copper(I) oxide, Na2S =Sodium sulfide, and CaCO3 = calcium carbonate.

If you are looking at covalent molecules such as H2O or N20, then you have a different set of rules N2O is dinitrogen monoxide, N2O3 is dinitrogen trioxide etc. etc.

So calling H2O, dihydrogen monoxide is perfectly fine, but know one ever does because it's common name is more readilly identified by the masses.

Provost Harrison · March 16, 2004, 15:26

...much less of a mouthful too

Az · March 16, 2004, 16:18

Quote:

This is killing me I'm a chemist, and I can comfortably tell you that covalent bonding does not define a molecule ( Ogie). The definition of a molecule is simply when more than one atom is connected together. This means that H2O is a molecule, NaCl, is a molecule, and H2 is a molecule. O, Na, Cl, and H, are atoms. The type of molecule that they are generally is classified by how they bond.

When it comes to nomenclature, dihydrogen monoxide is a perfectly fine way of naming it. The nomenclature rules depend upon the type of molecule that you have (ionic, covalent etc). When naming an ionic compound (generally identified because they contain a metal and a non metal) you state the root name of the cation followed by the name of the anion. for example NaCl = sodium chloride, Cu2O = Copper(I) oxide, Na2S =Sodium sulfide, and CaCO3 = calcium carbonate.

If you are looking at covalent molecules such as H2O or N20, then you have a different set of rules N2O is dinitrogen monoxide, N2O3 is dinitrogen trioxide etc. etc.

So calling H2O, dihydrogen monoxide is perfectly fine, but know one ever does because it's common name is more readilly identified by the masses.

Bah. the proper name is Oxidane, and that's it.

Quote:

The definition of a molecule is simply when more than one atom is connected together.

That's a very interesting definition. How would you isolate such a single molecule?

Combat Ingrid · March 16, 2004, 16:22

Quote:

Originally posted by centrifuge
NaCl is a molecule,

I know I said I was gonna quit this discussion, but I just can't help myself

I have a question to you: Where would you expect to find a NaCl "molecule"? Think carefully before you reply

orange · March 16, 2004, 16:24

The guy who started that site is from Newark DE

Go townies!

Az · March 16, 2004, 16:36

Quote:

Why not hydrogen hydroxide?

It's Oxidane, I am telling you.

Provost Harrison · March 16, 2004, 16:43

Quote:

Originally posted by Combat Ingrid

I know I said I was gonna quit this discussion, but I just can't help myself

I have a question to you: Where would you expect to find a NaCl "molecule"? Think carefully before you reply

We reach an interesting predicament. It isn't a molecule per se as it does not possess a covalent interaction between the atoms involved. However NaCl can be identified as the smallest unit available. And we can get down to semantics...the Na - Cl ionic interaction would possess an element of covalent nature, as the C - H bond would possess an element of ionic nature (dipole anyone?

). By the context of a purely covalent bond, the only thing that would qualify is a molecular element such as O2 or C (whatever allotrope). So you have to be careful by trying to define a molecule, or a molecular unit to be more accurate.

centrifuge · March 16, 2004, 16:47

Quote:

Originally posted by Combat Ingrid

I know I said I was gonna quit this discussion, but I just can't help myself

I have a question to you: Where would you expect to find a NaCl "molecule"? Think carefully before you reply

umm, in my salt shaker...

Several NaCl molecule form together into crystals.

I don't have to think hard about it, since anyone who has been educated on the subject, knows that NaCl is a molecule, formed by the ionic bonding of Na+ and Cl- . If you put it into a solvent such as water, it will break back into it's ions. The fact that it does this doesn't make it any less of a molecule.

Azazel, look in the glossary of any introductory chemistry book, and you'll see a definition similar to what I stated above, but I will guaruntee you that you will never see a definition that states molecules have to be covalently bonded.

Az · March 16, 2004, 16:52

At my Atkins general chemistry book, I remember very clearly they said that it's NOT a molecule. I was shocked, btw.

Provost, this is true. I think that the nature of the Na-Cl bond is around 90% Ionic, and the rest is covalent.

I think the question we must ask is, can we evaporate NaCl, and bring it to a state where small particles of NaCl float?