Question

Chapter 2 Problems 1. Calculate the molecular weight of a polyethylene molecule with n = 1000, and acrylic polymer, polymethyl methacrylate with n = 400. The isomers of the two are нсн. Polyethylene Polymethyl methacrylate mo 2. Estimate the coordination number (CN) for the cation in zinc blende (Zn) 3. Calculate the minimum radius ratio for a coordination number (CN) - 8 from the table 2.1. 4. Answer the following question in few sentences. (a) Briefly cite the main differences between ionic, covalent, and metallic bonding. (b) What is electronegativity? Metals generally have low electronegativity values of about 1.8. How do you associate this with high conductivity of metals? (c) Write down the typical bond strengths of C-C,C - HH - H covalent bonds and a H - H secondary bond. Briefly explain the mechanism behind the secondary bonding. (d) Based on the atomic number and valence electrons determine the possible number of covalent bonds for atoms of the elements: germanium, phosphorus, selenium, and chlorine.

Answer 1

And Molecular weight (number of carbon atoms). (Catomic weight), + (number of Hatoms) (Hatomic weight) + (number of O atoms ) Co atomic weight) Polyethene - C₂ Hy atomic weight c =R-01 h = 1000 H = 1.01 Molecular weight of Polythere = (2x12.01)+ (4x1-01) = 24.02 + 4.04 = 28.069/mol Total molecular weight of polythere = hx 28.06 = 1000x28.06 = 28060 Polymethyl methacrylate - CGO24g n=you Molecular weight = (5x12.0D + (8x101)+(2416) = 60.05 +8.08 + 32 = 100.13 g/mol Total molecular weight = nx 100.13 - 400 x 100.13 =40052 g/mol.