# What to say: "one mole of C atoms" or "one mole of C molecules"?

As we know, Please point out if I am wrong here
one molecule of CO = one mole of CO molecules = 6.223 X 10^23 number of CO molecules
If I split one molecule of CO, we get one C and one O. Here are my questions, What to say these ''one C and one O" one mole of C atoms and one mole of O atoms or ''one mole of C molecules and one mole of O molecules'' or just like above like ''one C and one O''?
Could you clarify it, please? I am confused

scottdave
Homework Helper
If you do a search, you can find some definitions of molecule as a "group of atoms" bonded, or "2 or more atoms...". I also found ones which stated it could be a single atom molecule, being the smallest unit of the substance which maintains all of the properties.

Single oxygen atoms are probably not going to stay that way. They are going to pair up and form O2 Oxygen molecules. Carbon atoms can be single or bond with other carbons in a lattice structure.
I would state a mole of atoms, if you are talking about the atoms. If it is a molecule (like O2) then I would say molecules.

DrClaude
DrClaude
Mentor
I also found ones which stated it could be a single atom molecule, being the smallest unit of the substance which maintains all of the properties.
The only case where I've seen this actually used is for noble gases.

In the present case, I see no reason to call C or O molecules.

The only case where I've seen this actually used is for noble gases.

In the present case, I see no reason to call C or O molecules.
Then what should I call ''C'' and ''O'' here in CO?

DrClaude
Mentor
Then what should I call ''C'' and ''O'' here in CO?
Atoms. Dissociating one mole of CO gives you one mole of C atoms and one mole of O atoms.

scottdave
Atoms. Dissociating one mole of CO gives you one mole of C atoms and one mole of O atoms.
One mole of CO means one mole of CO molecules here?

DrDu
I would speak of neither atoms nor molecules, here. Just say one mole of carbon or one mole of carbon monoxide or one mole of oxygen. With elements, it is understood that you refer to C or O, and not to O2. If you want to speak of moles of molecular oxygen, say one mole of dioxygen or O2. The mole is a macroscopic unit of substance, so usually it is not necessary to refer to the atomistic basis.

Borek
Mentor
One mole of CO means one mole of CO molecules here?
Yes.

Borek
Mentor
With elements, it is understood that you refer to C or O, and not to O2.
This is tricky, "one mole of oxygen" is ambiguous. It is best to elaborate what one really means by that.