Q 1 – Name the plastic whose sheets are used for packing liquids.
Ans. Polythene
Q 2 – What are polymers?
Ans.Polymers are compounds that are made up of same, small repeating units, joined together through bonds in a linear pattern.
Q 3 – Name one naturally occurring polymer.
Ans. Cellulose
Q 4 – Name the fibre used for making parachutes and ropes for rock climbing.
Ans Nylon
Q 5 – Which synthetic fiber is known as artificial silk?
Ans. Rayon fiber is known as artificial silk.
Q 6 – Which is the first fully synthetic fibre?
Ans. Nylon is the first fully synthetic fibre.
Q 7 – Write one disadvantage of synthetic fibre.
Ans. Synthetic fibres melt on heating.
Q 8 – What is cellulose?
Ans. Cellulose is a polymer made up of large number of glucose units.
Q 9 – What are the advantages of nylon?
Ans. Nylon fibre is strong, elastic and light. It is lustrous and easy to wash.
Q 10 – Write uses of bakelite.
Ans. It is used for making electrical switches, handles of various utensils, etc.
Q 11 – Write uses of melamine.
Ans. It is used for making floor tiles, kitchenware and fabrics which resist fire.
Q 12 – List the two ways in which synthetic fibres can be synthesised.
Ans. Synthetic fibres may be synthesised by two ways:
- By regenerating them from natural fibres, like in rayon.
- By using entirely chemicals and chemical reactions, like in nylon.
Q 13 – What are esters?
Ans. Esters are the chemicals which give fruits their smell.
Q 14 – What is rayon?
Ans. Rayon is a man-made fibre which is produced by the chemical processing of wood pulp, i.e., a natural substance.
Q 15 – What is polythene?
Ans. Polythene (Poly + ethene) is a type of plastic that is used for making commonly used polythene bags.
Q 16 – Is plastic bag non-biodegradable? Why?
Ans. Plastic bag is non-biodegradable because it takes several years to degenerate.
Q 17 – Can we store jams and pickles in plastic containers? Give reason.
Ans. We can store jams and pickles in plastic containers because plastics do not react with water and air and do not get corroded easily.
Q 18 – Do all plastics have same type of arrangement of units?
Ans. All plastics do not have the same type of arrangement of units. In some it is linear, whereas in others it is cross-linked.
Q 19 – Why is nylon used for making parachutes and ropes for rock climbing?
Ans. Nylon is used for making parachutes and ropes for rock climbing because nylon fibre is strong and can hold heavyweight.
Q 20 – List two uses of rayon.
Ans. The two uses of rayon are:
- It is used to make apparels like shirts, blouses, etc.
- It is used to make furnishings and upholstery.
Q 21 – List any two properties of rayon.
Ans. The two properties of rayon are:
- Rayon is a versatile fibre.
- It can be dyed in different colours.
Q 22 – Draw a diagram to show the:
(a) the linear arrangement of units in plastic.
(b) cross-linked arrangement of units in plastic.
Ans.
Q 23 – Write some advantages of synthetic fibres.
Ans. Advantages of synthetic fibres are:
- Synthetic fibres are strong and durable.
- They do not shrink.
- They are moth and insect resistant.
Q 24 – Define petrochemicals.
Ans. All the synthetic fibres are prepared by a number of processes using raw materials of petroleum origin, called petrochemicals.
Q 25 – What are plastics?
Ans. Plastics are those substances that are mostly synthetic in nature, obtained mainly from petrochemical sources and can be moulded into different shapes.
Q 26 – What is plasticity?
Ans. Plasticity is the property of materials by which they can be moulded into any shape.
Q 27 – What are thermosetting plastics?
Ans. Thermosetting plastics are those which when moulded once, cannot be softened again and lose their plasticity.
Q 28 – List any three properties of plastics.
Ans. The three properties of plastics are:
- They are non-corrosive in nature.
- They are light in weight and durable.
- They do not conduct heat.
Q 29 – Plastic bags create which kinds of problems?
Ans. Following problems are created by plastic bags:
- Plastic bag keeps on accumulating in the environment.
- It chokes drains.
- A stray animal can die if it accidentally swallows plastic bag.
Q 30 – What are the uses of polyester?
Ans. The uses of polyester are:
- It is used in making home furnishings and apparels.
- Polyester is used for finishing on guitars and pianos.
Q 31 – Why is it advised not to wear synthetic clothes while working in a laboratory or working with fire in the kitchen?
Ans. The synthetic fibres melt on heating. This is actually a disadvantage with synthetic fibres. If the cloth catches fire it can be very disastrous. The fabric melts and sticks to the body of the person wearing it. It is therefore advised not to wear synthetic clothes while working in a laboratory or working with fire in the kitchen.
Q 32 – Write some properties and uses of melamine.
Ans. Melamine is a versatile material. It resists fire and can tolerate heat better than other plastics. It is used for making floor tiles, kitchenware and fabrics which resist fire.
Q 33 – Describe about nylon. Write its uses and properties.
Ans. Nylon is the strongest amongst all the synthetic fibres. It is a fully synthetic polymer that is prepared from coal, water and air. It is a polymer of amides. It was made in 1931 for the first time. It was used as a supplement of silk when silk got deficient during World War II for many military applications. Uses of Nylon
- Nylon is used in toothbrushes, combs, etc.
- It is used to make parachutes, tents, ropes, etc.
- It is used to make socks and stockings as it is elastic.
- It is widely used for making clothes, carpets, etc.
Properties of Nylon
- It melts on heating.
- It absorbs less water.
- It is resistant to moths and fungi.
- It has high tensile strength.
- It is durable.
Q 34 – Write the advantages of synthetic fibres.
Ans. Synthetic fibres have many advantages as compared to natural fibres. Some of them are as follows:
- They are very strong and durable.
- They are cheaper in cost as compared to natural fibres.
- They absorb less water and are quick to dry.
- They do not shrink.
- They are very useful for saving our trees and animals as they are made up of chemicals.
- They are moth and insect resistant.
Q 35 – List the common varieties of polyester. Also, mention the natural fibres which are used for blending to enhance their properties.
Ans. Polyester could be blended with natural fibres to enhance its properties. The common varieties of polyester are:
- PET (Polyethylene terephthalate)
- Terrycot: It is made by blending polyester and cotton.
- Terrysilk: It is made by blending polyester iaiid silk.
- Terrywool: It is made by blending polyester and wool.
Q 36 – Explain the properties of plastics.
Ans. Plastics are those substances that are mostly synthetic in nature.
Following are the properties of plastics:
- Plastics are non-corrosive in nature, i.e., they do not react easily with air and water. They are unaffected by most of the chemicals in normal conditions.
- Plastics are the bad conductor of heat. They do not get heated up like metals.
- Plastics are non-biodegradable, i.e., they do not get decomposed by microorganisms.
- Plastics are very durable.
Q 37 – ‘Plastics are a hazard to the environment. Explain this statement.
Ans. Yes, plastics are a hazard to the environment. They make versatile materials but are very dangerous to the environment. Plastics are non-biodegradable in nature. It takes more than 100 years to decompose. If the use of plastics is not reduced, our earth would turn into a big garbage bin.
The major problems due to plastics are:
- If plastics are burnt, they evolve poisonous gases. These gases destroys the ozone layer of the earth and also pollute the environment.
- If the plastics are disposed in drains, they choke the drains causing waterlogging.
- If these plastics are swallowed by the innocent animals along with their food, they harm their di-gestive system which leads to their death.
- They are manufactured by the consumption of a large amount of petroleum.
Q 38 – List the strategies for plastic waste management.
Answer:
Some of the strategies for plastic waste management are:
- We should use paper bags and jute bags instead of using plastic bags.
- The government should ban the use of plastic bags.
- Plastics should be recycled to make other useful products which do not harm the environment.
- We should use a special garbage bins to dispose plastic wastes.
- We should not throw plastic wastes in water bodies.
- Practicing 4R’s principle, i.e., Reuse, Recycle, Reduce and Recover should be encouraged.