This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
Do any Atoms and Molecules(?) stick to each other WITHOUT heating above 200 degrees F.
ANWSER: YES NO
THERE ARE: FEW MANY
Were(?) can I find the details.
How do you break ELECTRON BONDS, just methods used (passing one molecule over another (at room temp, while heating them))? I do not need to know the exact proccess.
thanks - Anonymous
From the article: "An example of a macroscopically-sized molecule is DNA, a macromolecule" Being a macromolecule has nothing to do with being macroscopic. You could manufacture a DNA molecule that was long enough to become a macroscopic object, but must DNA molecules are microscopic objects. Memenen 14:21, 27 Dec 2004 (UTC)
Abstractly, a single atom may be considered a molecule, as it is when referred to collectively with molecules of multiple atoms, but in practice the use of the word molecule is usually confined to chemical compounds, of multiple atoms.
I am removing this from the article -- Not only is it confusing, but it contradicts the preceeding definition of molecule (two or more atoms, or before a previous edit, multiple atoms). Tygar 06:55, Feb 25, 2005 (UTC)
Avogadro's Law is stated a couple of times in the Wikipedia
[1] &
[2]
"equal volumes of gases, at the same temperature and pressure, contain the same number of molecules"
Therefore the noble gases (He, Ne, Ar etc) are made up of atoms that can also be described as monatomic molecules. There are intermolecular forces of attraction between the atoms of noble gases and they follow all the gas laws as do other simple molecules.
I agree with Unconcerned.
I believe that the DNA visibility example is useful in providing a feeling about the size and tangibility of molecules, and in making the concept less abstract. The way it was formulated also allowed for a few useful wikilinks. Therefore, I re-included the removed fragment.-- Unconcerned 17:33, 30 Mar 2005 (UTC)
I have reverted the edits from user:202.141.141.10 for the following reasons:
I felt these explanations were necessary since user:202.141.141.10 seems to have complained in the past about other editors' conservatorism.-- Unconcerned 10:54, 13 December 2005 (UTC)
Dr. Hallen, I am copying a question I have asked of you above, and you still have not answered. Please check below: --
Unconcerned 09:12, 15 December 2005 (UTC)
::You insist upon stating that a molecule is "the smallest particle of a pure substance composed of more than one atom". Take for example the substance
benzene; the fragment
C
H is the smallest particle of benzene that is composed of more than one atom. Yet, CH is not a molecule, and particularly not a benzene molecule. Your definition is
flawed and therefore should not replace a perfectly valid one.--
Unconcerned
17:44, 14 December 2005 (UTC)
I've grouped all possible definitions in a single paragraph, and included a few external links in support of each def. -- Unconcerned 12:26, 15 December 2005 (UTC)
Dr. Hallen, when did in your opinion the kinetic theory of gases abandon the concept of monatomic molecule? From what I know the concept is still very much being used in physics. -- Unconcerned 09:12, 15 December 2005 (UTC)
Dr. Hallen, please read through the following two fragments and explain why do you think the first one is not as concise and explicit as the second one?
*Molecules have fixed
equilibrium (or
average) geometries—bond lengths and angles—. A pure substance is composed of molecules with the same equilibrium geometrical structure.
*A molecule can be visualized as an entity having a fixed
equilibrium geometry—bond lengths and angles— however this geometry is constantly changing in an ensemble of molecules (a sample of a pure substance). Thus, a pure substance is composed of molecules with varying geometries, but averaged out on time it is a geometrical structure.
I've slightly re-worded the molecular geometry section in the hope to capture the idea of average geometry without conflicting with the rest of the paragraph. Please let me know how that works.
Many thanks and looking forward for a fruitful collaboration. -- Unconcerned 09:12, 15 December 2005 (UTC)
This will be an amusing and obvious answer for chemist, but nonetheless important for people discovering the entry of molecule.
Does the structural formula of a molecule represent, at any degree, the concrete, physical form of this molecule? If so, at what level does the shape is more precisely relating to the structural formula?
For example, one of the fatty acid in a phospholipid molecule seems to be a strait line because it is a chain of CH2. Does that mean part of this molecule is actually a real, concrete line(or a lineal form)?
Thanks in advance!
-- Enigma 21:11, 26 December 2005 (UTC)
Figure 1 of the article pretty much answers your question. A 2D formula does not tell you much about the 3D structure - at least not if you are not experienced in translating 2D into 3D (although good structural formulas will give you many 3D-hints). As you can see in figure 1, carbon atoms have four bonds in an tetrahedral manner so it is impossible for CH2 chains to build "lines". Instead they will form zig-zag lines which are, however, flexible due to bond-rotation. The best way to get an idea about 3D molecule structures is to use molecule model kits (real ones or computer-based ones). Cacycle 00:48, 27 December 2005 (UTC)
Thanks Cacycle, I appreciate. --
Enigma
08:54, 30 December 2005 (UTC)
Also it is important to note that a molecule can be in many different conformations (different shapes without changing connectivity) and be the same molecule. In fact most molecules are constantly changing such conformations as tmany bonds allow for rotation.
The definition of a molecule as "the smallest indivisible portion of a substance that retains chemical and physical properties" is widespread among encyclopaedias and vocabularies. However,it looks *very puzzling* to me. Most chemical and physical properties of a substance have sense only when we talk of a *set* of molecules together. For example,I see as plain nonsense asking something like "at what temperature/pressure will that single isolated water molecule boil/ice/melt?". I think no one will deny phase transitions of a substance are among the most basic physico-chemical properties of a substance,but at what number of molecules does this make sense?
Isn't the "word analogy" thingy a little too puerile? I mean, if I follow the paragraph and add carbon atoms (carbon black in a first approximation) to water molecules (tap water in another approximation)... Isn't there any other analogy -- if necessary at all?-- Unconcerned 10:08, 19 May 2004 (UTC)
I put the following "image caption" stuff here; generally, it's not advisable to try to put a full paragraph in a caption. Rather it's better to describe the caption in the body of the work; I'll leave it here for now.-- Sadi Carnot 13:34, 7 April 2006 (UTC)
A molecule really is the smallest unit of a substance which retains its chemistry. Thus, molecules of elemental He, Ne, Ar, Kr, Xe are monatomic. That's true whether these substances are in the form of gases, liquids, or solids. This isn't only a "kinetic theory of gases" thing; rather it's a general extension of the idea of a molecule as the last division you can naturally make and still retain the same chemical stuff (or the last division you can amplify and get the same chemical stuff). I think the article ought to start out that way, and then note that most molecules contain 2 or more atoms. There should also be mention of the fact that "molecule" has definition problems in many solids: where are the molecules in a salt crystal, a diamond, or bit of graphite? Many common solids aren't really composed of classical molecules. They just aren't! The concept really is a fully natural one ONLY in gases, and it is there of course that some molecules consist only of one atom.
Wiki should be simple, but never so simple as to tell the reader what isn't so. Do you want me to make a first pass at fixing this? Sbharris 02:30, 11 June 2006 (UTC)
i want to know about the molecular medicine!But in this page, i can't search this key words!Please help me!
please contact me on my yahoo messenger:" supershiva2006 "
thanks for your helping!
This is an archive of past discussions. Do not edit the contents of this page. If you wish to start a new discussion or revive an old one, please do so on the current talk page. |
Archive 1 |
Do any Atoms and Molecules(?) stick to each other WITHOUT heating above 200 degrees F.
ANWSER: YES NO
THERE ARE: FEW MANY
Were(?) can I find the details.
How do you break ELECTRON BONDS, just methods used (passing one molecule over another (at room temp, while heating them))? I do not need to know the exact proccess.
thanks - Anonymous
From the article: "An example of a macroscopically-sized molecule is DNA, a macromolecule" Being a macromolecule has nothing to do with being macroscopic. You could manufacture a DNA molecule that was long enough to become a macroscopic object, but must DNA molecules are microscopic objects. Memenen 14:21, 27 Dec 2004 (UTC)
Abstractly, a single atom may be considered a molecule, as it is when referred to collectively with molecules of multiple atoms, but in practice the use of the word molecule is usually confined to chemical compounds, of multiple atoms.
I am removing this from the article -- Not only is it confusing, but it contradicts the preceeding definition of molecule (two or more atoms, or before a previous edit, multiple atoms). Tygar 06:55, Feb 25, 2005 (UTC)
Avogadro's Law is stated a couple of times in the Wikipedia
[1] &
[2]
"equal volumes of gases, at the same temperature and pressure, contain the same number of molecules"
Therefore the noble gases (He, Ne, Ar etc) are made up of atoms that can also be described as monatomic molecules. There are intermolecular forces of attraction between the atoms of noble gases and they follow all the gas laws as do other simple molecules.
I agree with Unconcerned.
I believe that the DNA visibility example is useful in providing a feeling about the size and tangibility of molecules, and in making the concept less abstract. The way it was formulated also allowed for a few useful wikilinks. Therefore, I re-included the removed fragment.-- Unconcerned 17:33, 30 Mar 2005 (UTC)
I have reverted the edits from user:202.141.141.10 for the following reasons:
I felt these explanations were necessary since user:202.141.141.10 seems to have complained in the past about other editors' conservatorism.-- Unconcerned 10:54, 13 December 2005 (UTC)
Dr. Hallen, I am copying a question I have asked of you above, and you still have not answered. Please check below: --
Unconcerned 09:12, 15 December 2005 (UTC)
::You insist upon stating that a molecule is "the smallest particle of a pure substance composed of more than one atom". Take for example the substance
benzene; the fragment
C
H is the smallest particle of benzene that is composed of more than one atom. Yet, CH is not a molecule, and particularly not a benzene molecule. Your definition is
flawed and therefore should not replace a perfectly valid one.--
Unconcerned
17:44, 14 December 2005 (UTC)
I've grouped all possible definitions in a single paragraph, and included a few external links in support of each def. -- Unconcerned 12:26, 15 December 2005 (UTC)
Dr. Hallen, when did in your opinion the kinetic theory of gases abandon the concept of monatomic molecule? From what I know the concept is still very much being used in physics. -- Unconcerned 09:12, 15 December 2005 (UTC)
Dr. Hallen, please read through the following two fragments and explain why do you think the first one is not as concise and explicit as the second one?
*Molecules have fixed
equilibrium (or
average) geometries—bond lengths and angles—. A pure substance is composed of molecules with the same equilibrium geometrical structure.
*A molecule can be visualized as an entity having a fixed
equilibrium geometry—bond lengths and angles— however this geometry is constantly changing in an ensemble of molecules (a sample of a pure substance). Thus, a pure substance is composed of molecules with varying geometries, but averaged out on time it is a geometrical structure.
I've slightly re-worded the molecular geometry section in the hope to capture the idea of average geometry without conflicting with the rest of the paragraph. Please let me know how that works.
Many thanks and looking forward for a fruitful collaboration. -- Unconcerned 09:12, 15 December 2005 (UTC)
This will be an amusing and obvious answer for chemist, but nonetheless important for people discovering the entry of molecule.
Does the structural formula of a molecule represent, at any degree, the concrete, physical form of this molecule? If so, at what level does the shape is more precisely relating to the structural formula?
For example, one of the fatty acid in a phospholipid molecule seems to be a strait line because it is a chain of CH2. Does that mean part of this molecule is actually a real, concrete line(or a lineal form)?
Thanks in advance!
-- Enigma 21:11, 26 December 2005 (UTC)
Figure 1 of the article pretty much answers your question. A 2D formula does not tell you much about the 3D structure - at least not if you are not experienced in translating 2D into 3D (although good structural formulas will give you many 3D-hints). As you can see in figure 1, carbon atoms have four bonds in an tetrahedral manner so it is impossible for CH2 chains to build "lines". Instead they will form zig-zag lines which are, however, flexible due to bond-rotation. The best way to get an idea about 3D molecule structures is to use molecule model kits (real ones or computer-based ones). Cacycle 00:48, 27 December 2005 (UTC)
Thanks Cacycle, I appreciate. --
Enigma
08:54, 30 December 2005 (UTC)
Also it is important to note that a molecule can be in many different conformations (different shapes without changing connectivity) and be the same molecule. In fact most molecules are constantly changing such conformations as tmany bonds allow for rotation.
The definition of a molecule as "the smallest indivisible portion of a substance that retains chemical and physical properties" is widespread among encyclopaedias and vocabularies. However,it looks *very puzzling* to me. Most chemical and physical properties of a substance have sense only when we talk of a *set* of molecules together. For example,I see as plain nonsense asking something like "at what temperature/pressure will that single isolated water molecule boil/ice/melt?". I think no one will deny phase transitions of a substance are among the most basic physico-chemical properties of a substance,but at what number of molecules does this make sense?
Isn't the "word analogy" thingy a little too puerile? I mean, if I follow the paragraph and add carbon atoms (carbon black in a first approximation) to water molecules (tap water in another approximation)... Isn't there any other analogy -- if necessary at all?-- Unconcerned 10:08, 19 May 2004 (UTC)
I put the following "image caption" stuff here; generally, it's not advisable to try to put a full paragraph in a caption. Rather it's better to describe the caption in the body of the work; I'll leave it here for now.-- Sadi Carnot 13:34, 7 April 2006 (UTC)
A molecule really is the smallest unit of a substance which retains its chemistry. Thus, molecules of elemental He, Ne, Ar, Kr, Xe are monatomic. That's true whether these substances are in the form of gases, liquids, or solids. This isn't only a "kinetic theory of gases" thing; rather it's a general extension of the idea of a molecule as the last division you can naturally make and still retain the same chemical stuff (or the last division you can amplify and get the same chemical stuff). I think the article ought to start out that way, and then note that most molecules contain 2 or more atoms. There should also be mention of the fact that "molecule" has definition problems in many solids: where are the molecules in a salt crystal, a diamond, or bit of graphite? Many common solids aren't really composed of classical molecules. They just aren't! The concept really is a fully natural one ONLY in gases, and it is there of course that some molecules consist only of one atom.
Wiki should be simple, but never so simple as to tell the reader what isn't so. Do you want me to make a first pass at fixing this? Sbharris 02:30, 11 June 2006 (UTC)
i want to know about the molecular medicine!But in this page, i can't search this key words!Please help me!
please contact me on my yahoo messenger:" supershiva2006 "
thanks for your helping!