Question 2 the empty space that exists within a

Question 2
The empty space that exists within a crystal and surrounds the host species is called ______ .
(A) interstitial space
(B) vacancies
(C) phase boundaries
(D) substitutional impurities
(E) dislocation
A
Correct! Correct!
B
C
D
E
1 / 1 pts
Question 3
The ability of ________ to move is a critical factor that contributes to a given metal's mechanical
behavior.
1 / 1 pts
Question 4
For polycrystalline materials, crystal structure and chemical composition are preserved across a
grain boundary, whereas the crystal structure and/or chemical composition vary across a phase
boundary.

12/6/2018 Quiz 09 - Defects: Mat E 273
3/8
3 / 3 pts
Question 6
Compute the concentration (count per volume) of vacancies in copper at room temperature if the
lattice parameter of FCC copper is 0.3615 nm at room temperature (25 C, 298 K), and the
o
3 / 3 pts
Question 5
Compute the atomic density (the number of atoms per cm ... rather than the mass density
g/cm ) for a perfect crystal of silicon at room temperature, given that the room temperature
density and atomic weight of silicon are 2.33 g/cm and 28.09 g/mol, respectively.
Be sure to use values exactly as given and do not round until the final answer.
Use 6.022x10 , exactly, for Avogadro's Number.
(Soon I'll stop reminding you, but you can always go to the Quiz Info page to reference
conversions and constants.)
Be sure to use values exactly as given and do not round until the final answer.
Use 6.022x10 , exactly, for Avogadro's Number.
3
3
3
23
Hint:
An alternative way to solve this problem is to count the number of atoms within the unit cell (you
did this on Quiz 05 for the APF of the diamond cubic structure).
Dividing this count of atoms by the volume they occupy (the unit cell volume) yields the value we
are interested in here (atoms / cm ).
The lattice parameter of silicon is 5.431 Å.
Be sure you can compute this value using both approaches.
3
5e+22
Correct! Correct!
Correct Answers
Correct Answers