**** Avogadro's Number

[ManBearPig]

!!!!!!!!!!

Hate this shit. Tell me if my understanding of this is correct. This works because atoms are composed of protons and neutrons of standards mass and its basically just a conversion to make micro into macro (something tangible). So Avogadro's Number of whatever compound = mass in grams?

For some reason I can't wrap my mind around this lol...

 

[PsiStar]

it is not a ground hog ... but a ... ... ... mole

 

[PieIsAwesome]

Avocado's number describes how many "things" per mol. Things per mol.

 

[Rockinacoustic]

avagadro's number is the same thing as 1 mole. It's nomenclature (i.e. saying 12 equals 1 dozen)

It simply means that 1 mole of potassium chloride has the same number of particles as 1 mole of carbon monoxide. But they won't weigh the same.

 

[ManBearPig]

I just get confused with the conversion to grams I guess. I think I've got it more or less. It's just weird.

 

[Paperdoc]

By far, the "particles" referred to are molecules. One mole of any material contains an Avogadro's number of molecules of that. The mass of that amount is the Molecular Weight (in grams) of that material.

So, Hydrogen gas consists of two hydrogen atoms bonded together into a molecule. An Avogadros' Number of those molecules (6.023 x 10^23) will weigh the Molecular Weight of Hydrogen gas, which is 2.0 grams. Chlorine gas contains, again, two atoms (this time, chlorine atoms) bonded together into chlorine molecules. The Atomic Weight of Chlorine atoms is 35.5, so the Molecular Weight of Chlorine is 71.0 Thus, 6.023 x 10^23 molecules of chlorine gas weigh 71.0 grams.

A water molecule contains 2 hydrogen atoms plus one oxygen atom bonded together, for a total Molecular Weight of 18. So 6.023 x 10^23 molecules of water weigh 18 grams. (Because of the density of water, that amount is 18 ml in volume, or just over one tablespoon.)

A block of pure iron follows the same rule. It consists of just iron atoms, all kind of linked together in a matrix of shared electrons. Thus, the iron "molecule" is just one iron atom. Iron's Atomic Weight is 55.85, so an Avogadro's Number of iron atoms (molecules) weight 55.85 grams.

 

[esquared]

avagadro's number is the same thing as 1 mole. It's nomenclature (i.e. saying 12 equals 1 dozen)

It simply means that 1 mole of potassium chloride has the same number of particles as 1 mole of carbon monoxide. But they won't weigh the same.

This^

Based on the atomic weight/molecular weight, whether it is an element, say Carbon (atomic weight of 12) or a molecule, say NaCl (molecular weight of 58.44).


12 grams of carbon has 6.02^23 atoms of carbon.
and 58.44 grams of NaCl which has 6.02 ^23 molecules of NaCl.

Conversely, one mole of carbon weighs 12 grams and one mole of NaCl weighs 58.44 grams.

 

[SKORPI0]

http://en.wikipedia.org/wiki/Avogadro_constant

 

[ManBearPig]

I understand that all it is is a certain amount of "things." What I do not understand is how to go from carbon is 12 amu/atom to 12g/mol. I feel like a fucking retard! I understand all you have to do is just tack a "grams" on the end (basically), but I want to know how exactly I get from one unit to the other.

Thanks a lot for your help everyone!

 

[Gibsons]

I understand that all it is is a certain amount of "things." What I do not understand is how to go from carbon is 12 amu/atom to 12g/mol. I feel like a fucking retard! I understand all you have to do is just tack a "grams" on the end (basically), but I want to know how exactly I get from one unit to the other.

Thanks a lot for your help everyone!

That's kind of what's cool about it, you don't have to worry about any weird conversions. If you know the molecular weight, you know how many grams make a mole. Or a millimole, etc, You don't need to worry about the 6.023... part, it just works.

 

[esquared]

I understand that all it is is a certain amount of "things." What I do not understand is how to go from carbon is 12 amu/atom to 12g/mol. I feel like a fucking retard! I understand all you have to do is just tack a "grams" on the end (basically), but I want to know how exactly I get from one unit to the other.

Thanks a lot for your help everyone!

You just need to multiply the atomic number by the molecular mass constant, which is 1 g/mole


This may help:
http://en.wikipedia.org/wiki/Molar_mass_constant

 

[DrPizza]

What if you had a mole of moles?
http://whatif.xkcd.com/4/

 

[KaOTiK]

8675309

 

[T_Yamamoto]

I hate chem. Only reason I got an A was my friend.

 

[Squisher]

Avocado's number describes how many "things" per mol. Things per mol.

I'm pretty sure Avocado is more about Guaca-moles.

 

[alkemyst]

avocado is awesome.

 

[James3shin]

Each carbon atom has 12 amu (6 amu from protons + 6 amu from neutrons).

1 g = 6.022 x 10^23 amu

1 mol = 6.022 x 10^23 atoms

Using those conversion factors, 12 amu/atom = 12 g/mol of Carbon

 

[James3shin]

(12 amu / atom of C) * (6.022x10^23 atoms of C / 1 mol of C) * (1 mol of C / 12 g of C) =

6.022x10^23 amu per gram

 

[Ken g6]

The "things" are protons and neutrons. 1 mol of protons is approximately 1g. One mol of neutrons is also approximately 1g, even though it's slightly heavier than 1 mol of protons. Electrons are so light you can generally ignore their mass. So the "amu" above is roughly the mass of a proton.

 

[ManBearPig]

Gotcha, thanks all. I get stuck on these things sometime, lol. So it was basically as I thought, 1 mol of protons and neutrons is a gram, so it all works out. FUCK!

Appreciate it ATOT! :awe:

 

[OverVolt]

Call for a good time 6.022x10^23 everybody's got his number.

Protons and Neutrons are meh. Each element has its own mixture of isotopes. Thats why Carbon doesn't just have a molec. weight of 12, there is carbon 13, carbon 14, etc.

 

[Farmer]

What I do not understand is how to go from carbon is 12 amu/atom to 12g/mol.

That's the whole point. It is like that by construction, i.e., the mole was chosen to be what it is so this works out.

 

[Printer Bandit]

http://www.wimp.com/howbig/

 

[OverVolt]

Great chemists never die, they just reach equilibrium.

 

[OverVolt]

This was a story told to us by our chemistry master at school. A female student wished to make some potassium hydroxide solution (aqueous) and decided to throw a large lump of potassium into a bucket of water. Her professor observed what she was about to do, out of the corner of his eye and hurried towards her, and after confirming this was what she was intending to do, asked her first to stir the water in the bucket for five minutes before adding the potassium. She was puzzled and ran after him to ask the purpose of this action.
'It will give me time to get away' said the professor.

http://www.youtube.com/watch?v=uixxJtJPVXk