Hon Chemistry 12-1-21 Chapter 7 Test Overview

HONORS CHEMISTRY: God bless you as you study for the test! Here’s our overview of the test from today. By the way, in case you didn’t hear it, the answer to that last review problem was 2.798 x 10^23 formula units.

Have you been using the “Chapter 7 Stuff to Know & Know How to Do” sheet? It’s a great way to get organized in studying for the test. I know it seems like a lot, but you can do it!

First priority – make sure that you have memorized EVERYTHING. Then, go to The Physics Classroom and/or sciencegeek.net and make sure you can write and name chemical formulas. Practice, practice, practice!!! Then start practicing the different kinds of problems – do at least three of each one of them. And also try those on sciencegeek.net. That’s always some good practice. God bless – I’ll be praying for you!

Photo by Alexandre Chambon on Unsplash

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10 thoughts on “Hon Chemistry 12-1-21 Chapter 7 Test Overview

  1. Question: Is Kevlar actually bulletproof? Explain.
    Answer: Nothing in the world is purely bulletproof. Kevlar is pretty close…being extremely bullet resistant. Kevlar is a crosslinked polymer so it is very strong. It is also thermosetting due to it being crosslinked. The strength and heat resistance allows for a deflection of bullets and the heat they give off.

  2. Ask- Since there are natural polymers, are they all addition polymers? Because if they’re natural someone wouldn’t crosslink them or they would become synthetic.

    Answer- Actually most natural polymers are condensation polymers because when the monomers connect, they release a water molecule. So that water is a natural biproduct.

  3. Question: Like Luke insisted, is Teflon carcinogenic?

    Answer: Prior to 2013, Teflon was made using a manmade chemical called perfluorooctanoic acid (PFOA). There is some research linking PFOA to cancer, but not linking Teflon itself directly to cancer. After 2013, all Teflon branded prouducts are now PFOA-free.

  4. Ask: How did Goodyear discover vulcanization and what can we learn from his process?

    A: For years, Goodyear had been trying to discover a way to make a more temperature-unaffected rubber. It wasn’t until 1839 when he accidentally dropped some rubber and sulfur on a hot stove, and to his surprise, it resulted in the exact product he was looking for. We can learn a lot from this. As learning scientists, it may seem like we aren’t really going anywhere with our research sometimes, but we should keep going because a revolutionary discovery may hit us when we least expect it.

  5. Ask: If Goodyear found out a way to vulcanize rubber (cross-link the polymer chains of natural rubber with sulfur) can cross-linked polymers be broken down to become a linear structure? Kind of like reverse vulcanization.

    Answer: There is a process called “Inverse vulcanization” which uses large amounts of sulfur and a small amount of an additive. However, the structure of the polymers does not become linear. Scientists have merely synthesized a chemically stable sulfur-rich material from the result of refining petroleum and gas.

  6. Why is Styrofoam able to keep drinks both hot and cold?
    The tiny air bubbles present in the polystyrene foam or styrofoam slow down the progression of heat into the foam, and this slow rate can keep the contents inside cold. In the case of keeping things warm, the heat energy also moves very slowly out of the tiny air bubbles, and this reduces overall heat loss inside the styrofoam. This is why styrofoam makes for such a good insulator- the heat energy has a hard time flowing through the bubbles.

  7. Ask: how can we tell how different polymers are made up, like cross link, branched, or linear.
    Answer: you have to study the polymer at a molecular level to determine it’s bonds.

  8. If we are able to vulcanize a polymer with sulfur and make it stronger, are you able to add something to the polymer to make it not as strong?
    Answer: You can use inverse vulcanization reactions which is when a small amount of the polymer is combined with a mass amount of sulfur, weakening the bonds and so, it’s the opposite of vulcanization

  9. Ask: How did Carothers make nylon 66? What was its significance, and what is it used for today?

    Answer: He made it by synthesized using diamines which are used as monomers to prepare polyamides, polyimides, and polyureas. It was the first successful thermoplastic polymer which was used commercially. They are used as many things including brushes, tennis strings, and fishing lines.

  10. Ask-Why does polystyrene in Styrofoam appear differently than polystyrene in a plastic container?

    Answer- When mixing polystyrene with air, the air caused the polystyrene to create a foam that con be molded into different shapes. That’s how Styrofoam is made. Plastic can also contain polystyrene. It does not have a foamy appearance like styrofoam because this polystyrene has not been combined with air.

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