Saturday, September 18, 2010
Chapter 17, Problems 1-3
For 2 and 3, you need to convert a given mass or density of metal to charge or charge density. I think it's easiest to visualize this as a unit conversion problem, for example, the density of Al is 2.7 g/cm^3, which you want to convert to electrons/m^3. So multiply by unity in various forms to clear the dimensions. For example (1 mole / 27 g of Al), (How many atomis is it? / mole), (conduction electrons / atom), ...
Subscribe to:
Post Comments (Atom)
2 comments:
I'm still not understandign how to solve this problem. I know that the equation is
Vd= I/nqA
but I can't seem to figure out what n is. I have done denisty*atomic mass*avogadro's number and I'm not understanding it. I don't even know where to plug in the 3 for the electrons.
I suppose you're talking about problem #3? I did a very similar problem in lecture on September 16, around slides #11 and 12. (Slides from lectures are available on Blackboard as Course Documents, or you can watch a video recording of the lecture, avaiable from the same place.) The factor of three means that the number of electrons per volume is 3 times the number of atoms per volume.
Post a Comment