5. In the BeF2 crystal structure you may expect to have: a. the fluoride ion sur

ID: 1000557 • Letter: 5

Question

5. In the BeF2 crystal structure you may expect to have:

a. the fluoride ion surrounded by beryllium ions due to the smaller size of the anion.

b. the beryllium ion surrounded by fluoride ions due to the smaller size of the cation.

c. the structure exhibit directional bonding due to the percent ionic character of the bonds.

d. the fluoride and beryllium ions not equally distributed in the crystalline network.

6. A condition that will make a polymer totally non-crystalline is:

a. it is atactic

b. it is semicrystalline

c. it has a low glass transition temperature

d. the melting temperature is high

7. The following point defects cannot be present in metal crystalline structures:

a. vacancy

b. self interstitial

c. screw dislocation

d. Frenkel defect

8. Fick’s Second Law does not predict.

a. The concentration profile and time scale in diffusion.

b. Diffusion at steady state conditions follows a linear profile.

c. Diffusion at non-steady state conditions has curvature in the concentration profile.

d. The natural timescale in diffusion is temperature dependent.

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Please help

5. (b)

6. (b)

7. (c)

8. (c)

Best wishes

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