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Up Topic Welding Industry / Metallurgy / Atomic weights
- - By Superflux (****) Date 05-19-2011 12:46
Atomic weight vs volume
Ok,
W is 183.84 and Pb 207.2
Is a cc of each metal going to be in the same proportion of volume vs. weight?
Its been 40 years since hi-school chemistry class.
Parent - By rlitman (***) Date 05-19-2011 16:20
No.  Material density has very little to do with atomic weight.  It's more related to molecular arrangement.
Oh, and tungsten is significantly more dense than lead, even though it has a lower atomic weight.
Parent - - By G.S.Crisi (****) Date 05-20-2011 00:19
In the case of metals, density is related both to atomic mass (formerly called atomic weight) and atomic arrangement. In the case of salts (called ceramics by Material Science) instead of atoms they have molecules, that are formed by at least two atoms but can be many more.
In this case, molecular masses and arrangements are valid. 
The atomic (or molecular) arrangement is described by the "unit cells", that are the way, or geometric figures, in which the atoms (or molecules) organize themselves. To see how the unit cells look like (there are 14), enter Google and write "unit cells".

Let's give an example: iron. Knowing its atomic mass, atomic radius and its unit cell (body centered cube at room temperature), you can calculate theoretically its density, that will be almost equal to the actual one. Reason of the very little difference is that solid materials are not absolutely compact, they have empty spaces not occupied by atoms or molecules, called "vacancies" by Material Scientists. 
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - - By Superflux (****) Date 05-20-2011 04:51
rlitman,Crisi,
Thank you for the information. I should have known or remembered that. I was late and I took the easy way out by posting here. However all knowlege leads to more knowlege, and I now have other questions to investigate
I'm working on a personal project in my spare time. I know the machine will NOT work, but it is the finding out why and how that makes it fun.

Found this and thought I'd share after having my mind jogged
http://www.matweb.com/tools/weightcalculator.aspx
Parent - By Cumminsguy71 (*****) Date 05-21-2012 01:25
Boy, I want to thank them because that was just interesting reading!
Up Topic Welding Industry / Metallurgy / Atomic weights

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