F5 4.2 Natural rubber

Which of the following is not the example of natural polymers and its corresponding monomer?

• Natural rubber (isoprene)

• Starch (glucose)

• Cellulose (glucose)

• Protein (fatty acid)

What chemical is the most suitable to be used to speed up the coagulation of latex?

• Sodium hydroxide solution

• Sulphuric acid

• Methanoic acid

• Ammonia

What chemical is suitable to prevent the coagulation of latex?

• Ammonia

• Sodium hydroxide

• Sulphuric acid

• Methanoic acid

Which of the following is not the property of natural rubber?

• Sensitive to heat

• Elasticity decreases over time

• Easily oxidized by air

• Hard and brittle

What is vulcanization?

• A process whereby rubber is reacted with oxygen.

• A process whereby rubber is reacted with sulphur

• A process whereby rubber is reacted with methanoic acid

• A process whereby rubber is reacted with ammonia

What is the IUPAC name of the molecule shown in the diagram?

• 2-methylbut-1,3-diene

• Isoprene

• 3-methylbut-1,3-diene

Which of the following is true about vulcanized and unvulcanized rubber?

• Vulcanized rubber is less elastic than unvulcanized rubber

• Vulcanized rubber become soft and sticky easily compared to unvulcanized rubber

• Vulcanized rubber is stronger than unvulcanized rubber

• Vulcanized rubber is more easily oxidised than unvulcanized rubber

Based on diagram, what is X?

• Oxygen

• Hydrogen

• Sulphur

• Chlorine

What is the name of the Process Y?

• Sulphuration

• Vulcanization

• Unvulcanization

• Oxidation

This is the characteristics of unvulcanised rubber except..

• Low strength

• Easier to be oxidised

• More elastic

• Soft