Question

Chemical analysis of a silicon crystal reveals gallium at a level of 3.091X10^-2 atomic percent. Assuming that the concentration of thermally excited charge carriers from the Si matrix is negligible, what is the density of free charge carriers (free carriers/cm3) in this Si crystal?
stranik
1.598e14.
help
an explanation please?
i need a formula!
babol
The answer is not right, at least for me. anyone who knows how to do it and could write how ?
qwerty
Please, I need the formula!
Odesa
The answer 1.598e14 was not right for me too. Any ideas what happen and how to write it out?
chelo
What is the formula to use
chelo
Please, I need the formula!
Anon
The data for everyone of us is different as you noticed formula is required
Anon
Go to back to H4P2
Odesa
As its Si: 5.00*10^22 / (gallium level*10^-2) by someguy
Odesa
1.5455*10^19
aaa
gallium level*10^-2) what is this?
qwerty
What is the formula, please?
School girl
What about 3.091*10^-7? please
anon2
H4P2
Anonymous
1.6265*10^14 i have the answer for 3.091*10^-7
here the caculation
atomic percent*NA(avogadro number)

the solution/atomic volume of gallium
Anonymous
1.5442*10^14
this is the corect ones
qwerty
step1
(6.023*10^23)/(12.05)=m

step 2
m*(level of atomic percent)*(10^-2)