# Number of particles

1. Sep 20, 2011

### scientifico

1. The problem statement, all variables and given/known data
Do 5 L of Ne contain the same number of particles contained in 5 L of O ?

2. The attempt at a solution
The book say yes but I know that 5 L of Neon are 4.5 g and 5 L of Oxygen are 7.15 g.
So dividing them for their molecular weight I obtain 0.22 u and 0.44 u that aren't tha same :(
Where do I wrong?

Thank you!

2. Sep 20, 2011

### Dickfore

What kind of particles? If you are referring to atoms, then, according to Avogadro's Law yes, it is true. But, if you consider 20Ne as the most abundant isotope being consisted of 10 protons, 10 electrons and 10 neutrons, then there are 30 particles per atom of neon, while if you consider 16O as the most abundant isotope of oxygen, then there are 8 protons, 8 electrons and 8 neutrons per atom, i.e. 24 particles per atom. So, in this sense, neon would have more particles in the same volume.

3. Sep 20, 2011

### Staff: Mentor

O or O2?

4. Sep 20, 2011

### scientifico

if would be O2 it's right to me but it says O

5. Sep 20, 2011

### Staff: Mentor

I don't like nonsensical questions. If it contains just O, in a blink it will contain O2, and the number of "particles" goes down by half.