LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034

B.Sc.

AC 11

DEGREE EXAMINATION –CHEMISTRY

SIXTH SEMESTER – APRIL 2007

CH 6602 – CHEMISTRY OF MATERIALS

 

 

Date & Time: 20/04/2007 / 9:00 – 12:00          Dept. No.                                                     Max. : 100 Marks

 

 

Part A

Answer all the questions.                                                                                      10×2=20

1. Calculate the miller indices of crystal planes, which cut through the crystal axis at (3a, b, c).
2. Mention the differences between phosphorescence and fluorescence.
3. State the law of cryatallography.
4. Mention the differences between diamagnetic and paramagnetic materials?
5. Give one example of crystal growth by chemical vapor deposition method.
6. Mention the uses of the following crystals
7. a) Si b) quartz c) GaAs           d) CaF₂
8. Define liquid crystals.
9. An organic compound crystallizes in an orthorhombic system with two molecules per unit cell. The unit cell dimensions are 12.05, 15.05 and 2.69A^o. If the density of the crystal is 1.419g/cm³ , calculate the molar mass of the organic compound.
10. Differentiate anisotropy and isotropy.
11. State Curie-Weiss law.

Part B

Answer any eight questions.                                                                                  8×5=40

11. Explain BCS theory with an example.
12. How is the structure of compounds determined by single crystal X-ray diffraction             method?
13. Explain the process of crystallization by Bridgeman method?
14. Discuss the phenomenon of antiferromagnetism. How does it differ from ferromagnetic materials?
15. Describe the structure of sodium-β-alumina.
16. A paramagnetic material has a magnetic field intensity of 10⁴ A/m. If the susceptibility of the material at room temperature is 3.7 x 10^-3, calculate the magnetization and flux density in the material.
17. Mention the differences between ferroelectric and piezoelectric crystals with examples.
18. Explain the photo reduction of water with an example.
19. What is Schottky defect? Explain with an example.

 

 

 

20. What is Kirkendall effect? Explain.
21. The TG curve of 125.7 mg of sample that contained a mixture of

CaC₂O₄.H₂O (MW 146) and a thermally stable salt exhibited a weight loss of

6.98 mg at a temperature of 140°C corresponding to the loss of water. Determine the percentage of CaC₂O₄.H₂O in the sample.

22. How is flame fusion method helpful for the growth of crystals?

 

Part C

Answer any four questions.                                                                                 4X10=40

23. What are the types of non-stoichiometric defects? Explain with examples.
24. Explain the following:
25. a) Meissner effect b) working principle of sodium-sulphur battery. (5+5)
26. Draw and explain the crystal structure of spinel and inverse spinel with examples.
27. Describe the photolysis of water with an example.
28. Explain the following with examples:
29. a) Cheveral phases
30. b) hard and soft magnets (5+5)
31. a) Name the seven basic crystal systems and fourteen Bravais lattices. Give examples

with their interfacial angles and primitive values.

1. b) What are the types of lattices available depending upon the shape of the unit cell

and calculate the number of atoms per unit cell in each case.                         (6+4)

 

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