Last modified: Wed 12/31/1969 06:00:00 pm

Oklahoma State University

This is ACA # 7. It is OK to use your textbook or lecture notes from class, but if you can answers the questions without it that is OK too.

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Answer all of the questions below. If you do not know an answer enter CNA. However, it will help me the most if you answer each question with your best intuition/idea about what would be a reasonable answer.

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For an element that crystallizes in a face-centered cubic unit cell the relationship between the edge length (l) and the radius (r) of the element is

1. Calculate the radius (in centimeters) of a krypton atom. Krypton crystallizes in a face-centered cubic cell with an edge length of 5.59 x 10-8 cm. (NOTE: When entering numbers with exponents enter 1.98 x10-8 as 1.98e-8.)


2. Calculate the volume of the face-centered cubic unit cell for krypton.


3. How many krypton atoms are in a face-centered cubic unit cell?

krypton atoms

4. What is the mass of 1 mol of krypton in grams?


5. How many krypton atoms are in one mole of krypton?


6. Using the information in Q4 and Q5 calculate the mass of one krypton atom (in grams)?


7. Using your answers from Q3 and Q6 calculate the mass of krypton in a face-centered cubic unit cell.


8. Using you answers from Q2 and Q7 calculate the density of krypton in the solid phase.

grams cm-3

9. Is there anything about the questions that you feel you do not understand? List your concerns/questions.

10. If there is one question you would like to have answered in lecture, what would that question be?