Please change the answers to your own words Not from Google

Please change the answers to your own words.

Not from Google or any sources. ANSWER IT ON YOUR OWN WORDS.

Thanks!

4. Polyethylene consists of fibrous molecules of covalently bonded atoms tangled and interacting like the fibers of cotton ball. Weaker van der Waals forces act between the molecules with a strength that is inversely related to separation distance.

What properties of polyethylene can be attributed to the covalent bonding?

Properties of polyethylene that can be attributed to the covalent bonding are its strength, high ductility and malleability, low hardness, and low electrical conductivity.

What properties are most likely the result of the weaker van der Waals forces?

Weaker van der Waals forces would cause materials to be much less strong and the polymer chains that make up polyethylene would break apart much more easily.

If we pull on the ends of a cotton ball, the cotton fibers go from a random arrangement to an array of somewhat aligned fibers. Assuming we get a similar response from deformed polyethylene, how might properties change? Why?

- The deformed polyethylene would be stronger now that the molecules are more aligned.

Solution

The Pauling electronegativity of carbon is very close to the Pauling electronegativity of hydrogen. Due to the minute difference between these values , I would expect polyethylene to have carbon-hydrogen bonds with nearly 100% covalent character; and, of course, I would expect the carbon-carbon bonds present to also be covalent in nature.

It must be noted here that covalent carbon-hydrogen and carbon-carbon bonds are not the only types of bond present in our material, however. If the polymer chains were not held together by other forces, one might expect that they would slide past each other with great ease, and as a result, polyethylene would be a very weak material. In fact, van der Waals bonds hold adjacent chains close to one another.

Polyethylene contains covalent bonds within the polymer chains, and van der Waals bonds between the polymer chains. A single chain has strength similar to that of diamond, due to the covalent carbon-carbon bonds. The van der Waals bonds dominate the bulk properties, however, as they are what links the polymer molecules together. Thus, I would not expect polyethylene to be too strong, compared to the other materials mentioned here. I would expect it to have a very low hardness, and to be both very malleable and very ductile . but comparing to cotton Polyethylene would be stronger as the molecules are now aligned