Q-3 (a) Compute the density of totally crystalline polyethylene. The orthorhombic unit cell for polyvinylchloride shown in figure below, also, the equivalent of four repeat units is contained within each unit cell. (b) Using the answer to part (a), calculate the percent crystallinity of a branched polyvinylchloride that has a density of 0.905 g/cm³. The density for the totally amorphous material is 0.810 g/cm³. 0.255 nm 0.494 nm 0.741 nm