11. Write advantages of synthetic Fibres over natural Fibres. State how the production of synthetic fibre helps in the conservation of forest
12. What are plastics? Write the properties of thermosetting and thermoplastics. Write their uses.
13. Explain the following process: (a) Pasteurisation. (b) Fermentation
Answers
Answer:11.Synthetic fibers are more durable than most natural fibers and they readily pick-up different dyes. Natural fibers are much more sensitive than synthetic blends. Synthetic fibers burn more readily than natural which is a disadvantage of synthetic fibers.
12.thermosetting plastics have primary bonds between molecular chains and held together by strong cross-links. Thermoplastics have low melting points and low tensile strength. Thermosetting plastics have high melting points and tensile strength.
13.Pasteurization is the process of heating the object what ever it is for example milk it is heated then the harm full things are killed and made safe.. .. fermentation is the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat.
Explanation:
Answer:
11. Advantages. Synthetic fibers are more durable than most natural fibers and will readily pick-up different dyes. In addition, many synthetic fibers offer consumer-friendly functions such as stretching, waterproofing and stain resistance.
12. Thermosetting plastics have primary bonds between molecular chains and held together by strong cross-links. Thermoplastics have low melting points and low tensile strength. Thermosetting plastics have high melting points and tensile strength.
13. Pasteurization
Partial sterilization of a substance and especially a liquid (such as milk) at a temperature and for a period of exposure that destroys objectionable organisms without major chemical alteration of the substance.
Fermentation is the process in which a substance breaks down into a simpler substance.