3.Why is slow cooling required to produce pure crystals?

13. Show that the maximum packing ratio in the diamond structure is n/3/16. [Hint: The structure may be viewed as two interpenetrating fcc lattices, arranged such that each atom is surrounded by four other atoms, forming a regular tetrahedron.] 14. A quantitative theory of bonding in ionic crystals was developed by Born and Meyer along the following lines: The total potential energy of the system is taken to be ae? E = N-

An isotropic amorphous vitreous substance (meaning that it has the same refractive index regardless of the direction of vibration of light passing through it and that it does not have a regular crystal structure). crystals O spectrometer O fragments Glass

Proteins are chains of amino acids that can form in a variety of arrangements, one of which is a helix. What kind of IMF is responsible for holding the protein strand in this shape? On the protein image, show the locations of the ¡MFs that hold the protein together:

The closed structures ccp and hcp have the same number of coordination. Illustrate the difference in the arrangement of the spheres in both structures.

Why are there no more than 7 crystal systems ? What are quasicrystals ?

A crystal has a cubic unit cell of 4.2 Å. Using a wavelength of 1.54 Å at which 2θ value would you expect tomeasure the (111) peak?

Explain why each molecule has a higher melting point than the other in the pair. Match the words in the left column to the appropriate blanks in the sentences on the right. Make certain each sentence is complete before submitting your answer. Reset has a higher molar mass The main reason why Ti(s) has a higher melting point than Ne(s) is that Ti(s) has stronger dipole-dipole interactions The main reason why Fe(s) has a higher melting point than CCl (s) is that Fe(s) is an ionic compound can form hydrogen bonds The main reason why KCI(s) has a higher melting point than HCI(s) is that KCI(s) has metallic bonds The main reason why H20(s) has a higher melting point than H2S(s) is that H2O(s)

Please ans Q7. Correctly. (Gpt/Ai wrong ans not allowed)