is water more than the sum of its parts ?

I am confused by your comments. Is not a "property of water" that below 0 C it is a solid and above that it is a liquid (or gas at even higher temperatures)? Yet, you say one molecule of H2O is "water" - you seen to be contradicting yourself.

What do you define water to be?

If only: "Water is H2O." then why did you mention "properties"?

Your reply seems to self inconsistent.

 

Log in or Sign up to hide all adverts.

what's so confusing? H2O is a molecule of water.
a molecule cannot turn into a gas because you need at least 2 and a distance between them. the same analogy can be made for the solid and liquid phases as well.

 

Log in or Sign up to hide all adverts.

Your speaking of the properties of water is confusing when your definition seems to be (You did not answer the direct question asking for definition.) only "Water is H2O." Nothing about any of water's properties. Human were identifying water long be for its chemical composition was known. As I tried to make clear in longer post 117, human usage is essential to definitions. Defining words in other words only is circular and defines nothing but the relations between various symbols.

All humans know what water is (but may have different words /names for it). Only a tiny fraction know that it is the oxygen combustion ash of H2. They define it by its properties. A molecule of H2O has none of these defining properties so is not water for most humans but if you DEFINE water as H2O then clearly yes, by definition, a molecule of H2O is water.

 

Log in or Sign up to hide all adverts.

Billy T

what do you mean by this , " oxygen combustion ash of H2 " ?

I've heard a few yrs ago that H2O burns , is this what your referring to ?

explain

 

i think he means water is burnt hydrogen.

where did you hear water burns?
water cannot possibly burn.
you are essentially saying that iron oxide (rust) will rust.

 

sorry but I don't want to " think " this I want to " know " this

and through this BURNT hydrogen does the hydrogen atom actually change its characteristics ?

I doubt it

several yrs ago

 

Exactly. (I used the words I did because HCl is also "burnt hydrogen." i.e. HCl is the Chlorine combustion ash of hydrogen.)

Note that the chemical properties of any substance are determined by the electronic configuratuion of the outter shell electrons (their quantum mechanical "orbitals")

Thus, the chemical character of every atom changes when these orbitals change and they do change when part of a compound instead of an isolated atom. So yes, the properties of hydrogen when in H2O are different than when in H2 or even H which is hard to find.

PS. I am not sure but strongly suspect that it is possible to "burn water" at high temperatures if it (steam) is mixed with Fluorine. I.e. form the Fluorine combustion ash of Hydrogen, HF.

 

no. the atomic properties of hydrogen and oxygen remain unchanged.
the only difference being that neither have any bonds left.

 

If one wants to limit "combustion" (which is just fancy word for "burning") to burning in oxygen atmosphere, then using "oxidation" does that just fine. IMHO, combustion is the self-sustaining*, exothermic reaction with Oxygen, Chlorine or Fluorine. These processes are very similar and need a common word to describe them. "Combustion" is that word.

I do admit that "combustion" is often used to describe the most common (because Earth’s atmosphere contains O2 but not Cl or F) form of burning, but "oxidation" would be more precise.
----------------
*I require "self-sustaining" as I do not like to call iron "oxidation" burning or "combustion." I.e. when the energy is released so slowly that it dissipates to the environment instead of pre-heating the fuel that for me is not burning, or "combustion" but only "oxidation"

 

That is true (and "reduction" for the gain of electrons) but these two terms are for technical (specifically in chemical) context. It much the same as "work" or "energy" have quite well defined technical use and more general lay use.

I.e. the same word can have two different meanings.

For example, in lay use one can say:
"I don't have the energy to do the work of computing the answer.
Here the meaning is different from the technical use of these terms.

Likewise oxidation and reduction (meaning gain or losing electrons in a chemical reaction) is a technical uses of these terms.
"Combustion" I think is mainly, if not exclusively, a lay term, not a technical term.

So when I said:
"Water is the Oxygen combustion ash of hydrogen."
Or:
"HCl is the Chlorine combustion ash of hydrogen."

I am making a statement using the lay meaning of combustion.

Likewise when I say the fire is burning or oxidizing the wood, I am using the lay meaning (but it happens to be technically correct also). When I uses "oxidizing" instead of 'burning" I am further, but still in a lay sense, specifying that oxygen is being used, not that the oxygen is collecting electrons as if becomes part of the ash.

 

I only have one dictionary (Webster's Unabridged) and not even the one labled "Chemistry" mentions "oxygen."

(1) the act or process of burning.
(2a) Chem. Rapid oxidation accompanied by heat
(2b) Chemical combination accompanied by heat
(3) Violent excitement, tumult

(2b) would obviously include combustion by Chlorine or Fluorine. Even (2a) is probably the technical (gain of electrons) definition and definitely does not mention oxygen or require the use of any oxygen.

What specifically does your dictionary say? Does it state "combustion" requires oxygen?

 

No, that is not what you said. In post 133 you said:

"... look up the meaning of "Combustion" in a dictionary - not a chemical dictionary, but an 'english' dictionary, "in many cases it specifies that combustion reactions involve Oxygen. ..."

I did look combustion up in my dictionary and found no indication that oxygen was required for combustion. I asked what your dictionary said. I asked if it stated that combustion required oxygen? You have not answered.

Even if your "in many cases" were true, so long a significant fraction of dictionary define combustion as mine does: (2b)Chemical combination accompanied by heat or (1)Act or process of burning. Then my statement, which you were critical of, is perfectly OK. Namely one can say "HCl is Chlorine combustion ash of Hydrogen." etc. for fluorine and oxygen combustion to produce HF and H2O respectively.

Again if you want to specify, in lay usages, that the combustion is by oxygen then you say things like "Carbon burns with oxygen to produce CO2." or "Carbon combusted by oxygen yields CO2." and one can say: "Carbon combusted by Fluorine yields CF." (I think, not sure of my chemistry here)

Summary: Oxidation, in lay usage, is one form of combustion where the oxidizing (technical sense = removing electrons from the fuel) agent is Oxygen.

The oxidizing agent can also be Fluorine or Chlorine and combustion still is happening as "combustion" (as I said earlier) is just a fancy word for "burning." I assure you the Carbon, Hydrogen, wood, etc. can be burned if in a Fluorine or Chlorine atmosphere. Oxygen is not required for combustion. It just happens to be the most common oxidizing agent (technical sense) as Earth has Oxygen in its atmosphere.

 

guys

so is water more than the sum of its parts ?