[yellowrose87]

Hello all, 

I have the following question which I do not know how to answer:

I have silicon dioxide molecules (SiO2).
I know that the density is 6.83 x 10^22 atoms/cm^3.
I also know that there are 5 x 10^15 oxygen atoms/cm^2.

I was wondering how I could isolate that equation for either oxygen atoms or silicon atoms, in order to reduce the equation so that the only units remaining are "cm".

Thank you very much!

[shaggybill]

I might be way wrong here, but I thought dividing cm³ by cm² left you with just cm. Somebody will correct me, I'm sure.

[yellowrose87]

I might be way wrong here, but I thought dividing cm³ by cm² left you with just cm. Somebody will correct me, I'm sure.

The difference is that the first number involves "atoms" (meaning a mix of both the silicon and oxygen atoms), and the second number involves only "oxygen atoms".

[Borek]

Just because division of these two values gives cm doesn't mean that the result makes any sense.

YRose: what are you trying to calculate? And what do these densities mean? Especially the second one?  Where did you got it from?

[yellowrose87]

Just because division of these two values gives cm doesn't mean that the result makes any sense.

YRose: what are you trying to calculate? And what do these densities mean? Especially the second one?  Where did you got it from?

I am trying to calculate the length (thickness) of the silicon dioxide layer.
I got the second value from a journal paper.

[Borek]

But what does the second value mean? In what circumstances do you have such surface density of oxygen? And what do you know about your silicon dioxide layer?