Problem Set 3

Here is problem set:

Ch. 4: 4.1, 4.2 (to be handed in), 4.3, 4.4, 4.6, 4.7, 4.9.

Extra Problems:

    When Cu is heated its density will decrease for two reasons: thermal expansion and the fomation of vacancies. Calculate the drop in density when a piece of Cu is heated from 20 C to 1000 C assuming, a) no vacancies form. b) vacancies form.  Assume energy of vacancy formation is 0.9 eV/atom.  You can also assume that the volume coefficient of thermal expansion is equal to 3 x linear thermal expansion coefficient (see problem 4.9).  Comment on the relative values of each of the terms.

In class I said that thermal expansion is inversely proportional to the melting point or bond energy.  Look up the thermal expansions of NaCl and MgO. Do they support this conjecture? If not, what possible explanation can you give?  PS. I do not know the answer ;-) 

 Have fun y'all,