Atomic % & Weight % of Phosphorous in Solid Solution

[somebodyelse5]

Homework Statement

Given: 5x10^21 Phosphorous atoms/m^3 in solid solution in silicon

Find: atomic percent and weight percent of Phosphorous atoms

The Attempt at a Solution

I know how to solve for at. % and wt. % when given two values, I am not sure how to get the second value given the mixture is a "solid solution"

Do i have enough information to solve this?

Solid solution means that it is completely mixed, but how would that lead me to a density of silicon that I could used to solve for at.% and wt.%?

 

[wukunlin]

phosphorous in silicon...

this sounds like semiconductor doping to me
without any other information given I would assume this is the case, therefore I would decide the density of silicon by its cell structure and lattice parameter

 

[Borek]

Or just take density from any reliable source listing densities of elements. Amount of P is low enough to not change the density substantially.

 

[somebodyelse5]

My book has nothing to do with "Doping" and my class has not covered this. My book actually, does not even cover at. % or wt. %.

So I could just look up the density of silicon in as a solid and calc from there? Temperature does not matter here? (assuming that it doesn't, since the problem does not say)

 

[Borek]

Temperature doesn't matter - much. Density of solids doesn't change significantly with temperature (doesn't mean it doesn't change at all).

 

[somebodyelse5]

thanks guys, looks like i just made this problem a bit more difficult than it had to be. I am going to use a density in g/cm^3 and convert it to atoms/m^2 and calculate at.% and wt. % from there.