This topic contains a solution. Click here to go to the answer
« previous next »

Author Question: Why is the cis form of polyisoprene softer than the trans form? What will be an ideal ... (Read 42 times)

Redwolflake15

  • Hero Member
  • *****
  • Posts: 569
on: Aug 19, 2018
Why is the cis form of polyisoprene softer than the trans form?
 
  What will be an ideal response?

Question 2

In some applications, such as grilles for automobiles, engineering plastics such as PET compete with SMC and also with some metals such as zinc, which can be cast or even injection-molded. What would be the three inherent advantages of each of the material types in this kind of application?
 
  What will be an ideal response?

Question 3

What is the mechanism and thermodynamic explanation for why elastomers recover to their original shape after being elastically stretched?
 
  What will be an ideal response?


Related Topics

Need homework help now?

Ask unlimited questions for free

Ask a Question
Marked as best answer by a Subject Expert

Carliemb17

  • Sr. Member
  • ****
  • Posts: 325
Reply #1 on: Aug 19, 2018
Answer to Question 1

The cis form will not pack together as easily as the trans form. Hence, there are fewer intermolecular attractions in the cis form and the molecules can slide over each other more easily. This ease of sliding and absence of intermolecular attractions means that the cis form is softer than the trans.

Answer to Question 2

PET: cost, production time, and processability SMC: strength, durability, and equipment costs
Zinc: weatherability, appearance, and marketability

Answer to Question 3

When an elastomer is stretched the molecules become more ordered. This causes a decrease in entropy. Since entropy naturally tends to increase, when the stretching force is removed the natural tendency of entropy to increase supplies the energy for the molecules to return to their more energetically favored, random configuration.


Redwolflake15

  • Member
  • Posts: 569
Reply 2 on: Aug 19, 2018
Gracias!

JCABRERA33

  • Member
  • Posts: 344
Reply 3 on: Yesterday
Wow, this really help

« previous next »
 

Did you know?

Dogs have been used in studies to detect various cancers in human subjects. They have been trained to sniff breath samples from humans that were collected by having them breathe into special tubes. These people included 55 lung cancer patients, 31 breast cancer patients, and 83 cancer-free patients. The dogs detected 54 of the 55 lung cancer patients as having cancer, detected 28 of the 31 breast cancer patients, and gave only three false-positive results (detecting cancer in people who didn't have it).

Did you know?

There are approximately 3 million unintended pregnancies in the United States each year.

Did you know?

In most cases, kidneys can recover from almost complete loss of function, such as in acute kidney (renal) failure.

Did you know?

Patients who have been on total parenteral nutrition for more than a few days may need to have foods gradually reintroduced to give the digestive tract time to start working again.

Did you know?

If you use artificial sweeteners, such as cyclamates, your eyes may be more sensitive to light. Other factors that will make your eyes more sensitive to light include use of antibiotics, oral contraceptives, hypertension medications, diuretics, and antidiabetic medications.

Bipolar disease. The term bipolar means “pertaining to two poles.” The individual with this form of Bipolar disease. The term bipolar means “pertaining to two poles.” The individual with this form of
Asthma. (a) A normal bronchiole. (b) An asthmatic bronchiole. During an asthma “attack,” the bronchi Asthma. (a) A normal bronchiole. (b) An asthmatic bronchiole. During an asthma “attack,” the bronchi
Instructions for Completing the CMS-1500 (02/12) Claim Form Continued Instructions for Completing the CMS-1500 (02/12) Claim Form Continued
Instructions for Completing the CMS-1500 (02/12) Claim Form Continued Instructions for Completing the CMS-1500 (02/12) Claim Form Continued
How to graph quadratic equations that are in factored form y=a(x−r)(x−s) How to graph quadratic equations that are in factored form y=a(x−r)(x−s)
The B-form DNA double helix The B-form DNA double helix
Video: HIV Infection: Viral life cycle

For a complete list of videos, visit our video library