In: Mechanical Engineering
Mark Each One True (T) or False (F)
33. Polymers have only covalent bonding and no other type of bonding.
34. Weight average molecular weight and number average molecular weight are the same.
35. Teflon is the same structure as polyethylene but with one out of every four H replaced by F.
36. Organic polymers have C-C bonding.
37. Thermoset plastics are easily melted to form recycled products.
38. Ceramics at room temperature can have both elastic and plastic deformation in tension if the stress is high enough.
39. The lowest density structural metal is Mg.
40. Ti is used in biomedical implants.
41. Wrought iron has less than 0.008 wt.% C and is very soft and easy to form.
42. Cast iron has high amounts of carbon (2-4.5 wt.%) are is relatively hard and brittle.
43. Stainless steels contain Cr to prevent corrosion.
44. The higher the hardenability, the more difficult it is for a steel to transform to martensite when quenched from an annealing temperature.
45. Ceramics can have mixed ionic-covalent bonding.
46. In general, polymers are more ductile than metals.
47. The fracture stress for most polymeric materials is lower than most metals.
48. Polyvinyl chloride (PVC) is made with only Cl and C atoms.
49. SiO2 based glasses have an amorphous structure.