Self Assess 4.2 – Chemistry Form 5 Chapter 4


Question 1:
Name the polymer for natural rubber.

Answer:
Polyisoprene


Question 2:
The presence of acid in latex causes latex to coagulate.
(a) State the function of acid in the coagulation process of latex.
(b) Describe the coagulation process of latex.

Answer:
(a) The presence of hydrogen ions, H+ in the acid neutralises the negatively charged protein membrane.

(b)
– Hydrogen ions, H+ in the acid neutralise the negatively charged protein membrane.

– Rubber particles collide with one another that lead the protein membrane to break.

– Rubber polymers entangle that cause latex to coagulate.


Question 3:
What is the advantage of the irradiation vulcanisation process over sulphur vulcanisation process?

Answer:
Free from sulphur and chemical allergies.


Question 4:
Compare and contrast vulcanised and unvulcanised rubber.

Answer:
Similarity: Vulcanised and unvulcanised rubber originate from latex.