interatomic spacing of iron atoms


by sailormoon
Tags: density, interatomic spacing, iron atoms
sailormoon
sailormoon is offline
#1
Jun30-11, 09:16 AM
P: 2
3.2kg of iron is required to make a hollow spherical shell having inner radius (r=3cm).outer radius(r=5cm).

i)estimate density of iron. (ans :6.585g/cm^3) -not sure if its correct though
ii) using (i),est interatomic spacing of the iron atoms. the atomic mass of iron is 55.9u.

need help in (ii).is there like a formula for it?
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SpectraCat
SpectraCat is offline
#2
Jun30-11, 09:34 AM
Sci Advisor
P: 1,395
Quote Quote by sailormoon View Post
3.2kg of iron is required to make a hollow spherical shell having inner radius (r=3cm).outer radius(r=5cm).

i)estimate density of iron. (ans :6.585g/cm^3) -not sure if its correct though
ii) using (i),est interatomic spacing of the iron atoms. the atomic mass of iron is 55.9u.

need help in (ii).is there like a formula for it?
Just report the avg. distance between the atomic centers ... in other words, assume atoms are point particles ... you should be able to answer the question using the appropriate manipulation of the quantities you have (i.e. density, mass, volume and atomic mass of iron).
Jacques_L
Jacques_L is offline
#3
Jul1-11, 01:42 PM
P: 82
Your calculation of density is false - and not plausible, by the way.

You lack a data to be able to evaluate the interatomic distance : the crystallograpic cell and the motive in the cell.
The most simple lattice for the calculation is the face-centered cubic, but it rarely occurs in steels at room temperature, only in nickel alloys and manganese alloys (The Hadfield steel for instance). In a cfc an iron atom has 12 close neighbours. There are 4 atoms in the cubic cell.

All the other steels and pure iron are centered cubic at room temperature, with 8 + 6 neighbours. And they are ferromagnetic.
You easily find the parameter of the cc cell in the litterature, and on the net. There are 2 atoms in the cubic cell.


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