CAN YOU ANSWER QUESTION 3 THROUGH 9 FOR ME PLEASE

Questions to be investigated

What effect do intermolecular forces have on the properties of a substance?

Procedure/Description of Lesson

The objective of this experiment is to cross-link a polymer and observe the changes in the physical properties as a result of this cross-linking. The changes in physical properties of a cross-linked polymer are also studied as the temperature is varied.

Review of Scientific Principles:

If a substance springs back to its original shape after being twisted, pulled, or compressed, it is most likely a type of polymer called an elastomer. The elastomer has elastic properties (i.e., it will recover its original size and shape after being deformed). An example of an elastomer is a rubber band or a car tire.

The liquid latex (white glue) which you use contains small globules of hydrocarbons suspended in water. The silly putty is formed by joining the globules using sodium borate (a cross-linker). The silly putty is held together by very weak intermolecular bonds that provide flexibility around the bond and rotation about the chain of the cross-linked polymer.

Real-World Connections

The manufacture of synthetic fabrics, plastics, and rubbers are all based on the same science as this activity.

Materials and Supplies

4% Borax solution (sodium borate in washing soda)

55% White Glue solution in water

Beakers

Wooden sticks

Newspaper

Access to a light bulb and freezer

Procedure:

1. Put on safety gear- gloves, apron and goggles
2. Your sample container has 20 mL of the Elmer's glue solution.
3. To this, add the 10 mL of the cross-linker (borax solution) that is provided in small tube.
4. Immediately begin stirring the solutions together using the wooden stick.
5. After a couple of minutes of mixing, the silly putty should be taken out of the container and kneaded in the hands. Don't worry about the material sticking to your gloves as these pieces will soon mix with the larger quantity with which you are working. Continue to knead until the desired consistency is reached. (Material is no longer sticking/adhering to gloves)
6. Using a ruler to measure, drop the ball from a height of 30 centimetres. To what height does it rebound?
7. Stretch the silly putty slowly from each side.
8. Compress the silly putty back into a ball.
9. Pull the silly putty quickly from each side and compare the results.
10. Place the silly putty on some regular newsprint and press down firmly.
11. Remove the silly putty from the newsprint and make observations.
12. Repeat the same procedure on a comic section/picture of the newspaper. The silly putty is non-toxic and safe to handle so you can put it in a zip-lock bag and keep it at home.
13. Follow good laboratory procedure and wash your hands with soap and water when you have finished the experiment.

Data and Analysis:

Height of the rebound _________ cm.

Observations of pulling the silly putty slowly:

Observations of pulling the silly putty quickly:

Observations of the silly putty on newsprint:

Observations of the silly putty on the comic's section of the newspaper:

Questions:

1. How do the physical properties of the glue and water mixture change as a result of adding the sodium borate?

Ans:As I started adding sodium borate, the water mixture or the glue started to become gel and becomes more and more viscous due to formation of cross-linking bonds. It will become thick and stretchy.

2. What would be the effect (your thoughts) of adding more sodium borate solution?

Ans:The material will become more solid or rigid.

3. What does the ratio of the height drop to that of the rebound distance tell us/indicates?

4. Who in the class had the ball with the most elasticity?

5. How did you decide on whose ball was most elastic?

Place your ball in the refrigerator for 10 minutes. Recheck the bouncing portion of this experiment.

6. What are your observations? Was there a change in the rebound height?

7. Why do you think this was observed?

-Now place your ball about 6 inches from a light bulb for about 5 minutes and again recheck the bouncing portion of this experiment.

8. What are your observations? Was there a change in rebound height?

9. Why do you think this was observed?