chem question (STP)

[xlr8]

The number of atoms in 22.4 L of oxygen at STP = Avogadros number

I'm having trouble with this. The way I see it is that at STP and 22.4L, there is 1 mol O2 = 6x10^23 molecules of O2 for each 22.4 L, and so there are 2 atoms of oxygen in each molecule, giving me 12 x 10^23 atoms.

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[werd]

The number of atoms in 22.4 L of oxygen at STP = Avogadros number

I'm having trouble with this. The way I see it is that at STP and 22.4L, there is 1 mol O2 = 6x10^23 molecules of O2 for each 22.4 L, and so there are 2 atoms of oxygen in each molecule, giving me 12 x 10^23 atoms.

the initial premise is incorrect. the number of gas molecules in 22.4L at STP equals Avogadro's number. it's molecules, not atoms.

 

[xlr8]

According to kaplan:

the number of atoms in 22.4 liters of oxygen at STP = Avogadro's number

edit: (a PS discrete in FL 5)

 

[Bre]

Then Kaplan is wrong. You are correct in that the number of MOLECULES = Avogadro's Number, but the number of ATOMS = 2xAvogadro's Number

 

[xlr8]

I thought it was too, but I remember someone explaining why it was correct in a previous post.

 

[RPedigo]

You can read my explanation here:

http://forums.studentdoctor.net/showthread.php?t=423528

If you have any questions about it, just let me know and I'll clarify.

To summarize: 22.4L will give you a mole of oxygen molecules, so 2 moles of oxygen atoms. [oxygen is diatomic]
Therefore, if a question asked you how many liters for a mole of oxygen atoms, you'd say 11.2L.

 

[RPedigo]

This was addressed to me via private message, but I hate answering questions via PM since other people could benefit from a public discussion.

So 1 mol of O2 molecules = 2 mol O atoms?

STP confuses me sometimes because it seems like all the relations don't hold at times. But what I've learned is that:

1 mol X = 22.4 L

Is this correct?

In this case the reason is changes is because there are technically 2 mol atoms?

"So 1 mol of O2 molecules = 2 mol O atoms?"
This is correct. That's because there are two oxygen atoms per oxygen molecule.

"1 mol X = 22.4 L"
Yes, you just have to be careful: a mole of what?

1 mole of oxygen molecules contains 2 moles of oxygen atoms.

Just remember a mole is a really big number, so for visualization, we can simplify it... let's do a dozen

O2, O2, O2, O2, O2, O2, O2, O2, O2, O2, O2, O2

That's twelve oxygen molecules.
There are twenty-four oxygen atoms.