What Is The 12C Molecule?

[Gherkins]

Hello. What is the 12c (Or c12) molecule?

[sunny-dave]

Carbon (an element not a molecule) has atomic weight 12

https://en.wikipedia.org/wiki/Carbon-12

[bhg481]

Most elements exist in several forms, called isotopes. They are different by having a different number of neutrons in the nucleus.
C12 has 6 protons and 6 neutrons in the nucleus, hence atomic weight around 14.
C14 has 6 protons and 8 neutrons in the nucleus, hence atomic weight around 14.

[Kidas]

C-12 could be one of two things, depending on context.

As Dave says, could be carbon-12 (a stable isotope often used to date historical artefacts when the ratio of carbon-12 to cabon-14 (a slightly unstable isotope).

Or it could be a molecule (often organic) that comprises 12 carbon atoms as wel as others such as hydrogen, oxygne, nitrogen.

Common sugar (Sucrose) is a C-12, often described as C12 H22 O11.

[Gherkins]

Hello Sunny-Dave. Carbon 12 is a molecule, made of 12 carbon atoms no?

It apparently accounts up to 98.93% of the element carbon. Would this mean, as we're carbon lifeforms, we're majority composed of carbon 12?

[Gherkins]

Thank you for the other replies. bhg481, do you mean an atomic weight of 12?

Thank you for your reply Kidas. It was almost on the lines of my query.

[bhg481]

Carbon is an element. Carbon commonly comprises 2 main isotopes 98.93% C12 and the remainder C14.

[bhg481]

Sorry Gherkins, C12 has atomic weight 12 and C14 has atomic weight 14.

[Buenchico]

>>> Would this mean, as we're carbon lifeforms, we're majority composed of carbon 12?

Oxygen is the main element in the human body. (It's not there as a gas but bonded into hydrocarbons):
https://upload.wikimedia.org/wikipedia/commons/thumb/f/fd/201_Elements_of_the_Human_Body-01.jpg/1280px-201_Elements_of_the_Human_Body-01.jpg

[Gherkins]

If C-12 can be an organic molecule, would that not be what we're composed of? (Along side other elements)

[Kidas]

No.

Carbon can link to itself and make chains of 2 atoms (ethylene); 3 atoms (propylene), 4 atoms (butadiene), 5 atoms (isoprene, and so on, in more or les any combination.

All organic life (on this planet, at least) is made up of carbon-based molecules that might have any number of carbon atoms.

SOme are big molecules (proteins, for example could have hundreds of thousands of carbon atoms) some are smaller.

Look at this for some background:

https://opentextbc.ca/anatomyandphysiology/chapter/2-5-organic-compounds-essential-to-human-functioning/

[Kidas]

Gherkins, you might be confusing the two different meanings of C12.

Carbon-12 is an atom of carbon. It is made up of a nucleus containing 6 protons and 6 neutrons as well s a cloud of 6 electrons.

Carbon-14 is an atom of carbon (called an isotope because it is the same chemically as Carbon-12 but has a different neclear structure). it is comprised of 6 protons and 8 neutrons as well as a cloud of 6 electrons.

Carbon-12 is the most common isotope of atomic carbon.

Chemical interactions tend to be defined by the number and arrangements of the electrons, and are more or less independent of the nucleus.. Thus the chemical behaviour of carbon-12 is very similar to the chemical behaviour of carbon-14

As we move into chemistry (on a scale a few million times larger than the nucleus), most organic molecules are composed of a string of carbon atoms forming a backbone. Onto this backbone, other atoms arrange themselves to form organic molecules.

Those other atoms include oxygen, nitrogen and above all, hydrogen.

SO if you have a molecule (such as sucrose) of 12 carbon atoms, that would be a C12 compound. (usually the 12 is a subscript).

You would be right in saying that humans as well as other life forms are made up of various molecules based on carbon, in a wondrous variety of combinations.

Other atoms that have this ability to link to themselves include sulphr and silicon. So in theory, it would be possible to create life based on those atoms, rather than carbon. It would be life, but not as we know it, Jim.

[bhg481]

Gherkins - you seem to be confused as to what is an element, a molecule and a compound.
An atom is the smallest particle of a chemical element that can exist.
A molecule is two or more atoms of the same element bonded together.
A compound is atoms of different elements bonded together.
So oxygen is an element, O2 is a molecule (two oxygen atoms bonded together) and CO2 is a compound (a carbon atom bonded with 2 oxygen atoms).
To the best of my knowledge carbon does not form molecules but does form
compounds and, because of its nature, can form compounds containing long strings of carbon atoms with atoms of other elements hanging on to the string.

[Kidas]

bhg - good post

Strictly, there are molecules of carbon (with no other elements)
Graphite and diamond are the most well-known, but the most fun is Buckminster-fullerene (C50 and C60) (Buckyballs) as well as Bucky tubes, and that favourite of so many of gee-whizz science programmes, graphene

[Peter Pedant]

yeah I think he is confused between the atomic weight of carbon ( not molecular weight) and
di-saccharides.... which have 12 carbon atoms as a backbone

[Gherkins]

Thank you for the comments all. I find it takes me a while to respond sometimes, so other answers can come into play before I can conduct my own response.

My interpretation of 'c12' is that it is a stable carbon isotope. This is why I thought we could be made of c12, then when we 'die' our carbon goes from stable, to unstable. Being c14 or 13.

[bhg481]

Gherkins - I think you are misunderstanding "unstable". C-14 is unstable, with a half-life of nearly 6000 years, and is formed by atmospheric nitrogen reacting with cosmic rays. Living animals eat plants (directly or indirectly) so their body contains mainly C-12 but some C-14. After death the C-14, being unstable, decays to form other elements so the ratio of C-12 to C-14 increases with time, thus enabling the date of death to be estimated.

[Gherkins]

Fascinating bhg. Thank you very much for your insight. How amazing is it, that we have the ability to determine how long something has existed by the ratio of c12 to c14.