The number of vacancies in some hypothetical metal increases by a factor of 3 when the temperature is increased from 981 C to 1250 *C. Calculate the energy for vacancy formation (in J/mol) assuming that the density of the metal remains the same over this temperature range. i J/mol Germanium forms a substitutional solid solution with silicon. Compute the weight percent of germanium that must be added to silicon to yield an alloy that contains 3.44 1021 Ge atoms per cubic centimeter. The densities of pure Ge and Si are 5.32 and 2.33 g/cm, respectively. The atomic weights for germanium and silicon are 72.64 and 28.09 g/mol, respectively. wt% For Si to which has had added 4.0 10-6 at% of arsenic, calculate the number of As atoms per cubic meter. (Hint: use Equation N1 = CA Pl NAC1 + Al (100 - C1) P2 -). i atoms/m