Which of the following statements is/are correct?
Synthetic fibres do not absorb moisture and polyester is not derived from cellulose, it is a synthetic fibre.
Pre-weighed pieces of cloth of nylon, cotton, silk and wool of equal measurements are taken and soaked in a beaker filled with water. After a few minutes, the cloth pieces were taken out of the beaker and weighed again. Which of the following options places them in the correct order of their final weights?
Higher the water absorption capacity, more will be the final weight. Thus, the correct order of their final weights will be, Wool > Cotton > Silk > Nylon.
Why is it not advisable to wear clothes made up of synthetic fibres in hot and humid weather?
Clothes made up of synthetic fibres do not absorb water and do not allow the air to pass through. In hot and humid weather, these clothes stick to the body and make us feel uncomfortable.
A brief information about three different plastics is given below :
The correct option is C.
Polyethylene is the thermoplastic that can be rolled into sheets.
Polyvinyl chloride (PVC) is one type of thermoplastic polymer that is currently construction-related to simple electric wire insulation and coatings.
Bakelite is a kind of thermosetting plastic which is a bad conductor of heat and electricity. Because of this property it is used for making electric plugs, switches, plug boards, etc.
Which of the following statements about plastics are true?
The correct option is C.
Plastic polymer unit can be arranged either in a linear or cross-linked pattern. Linear polymers are those in which the polymer chains do not contain long-chain branches. Plastic polymer can also be classified as branch polymer. Cross-linked polymers, on the other hand, are those in which chemical bonds are formed between adjacent polymer chains, so that a network structure forms.
Melamine is a plastic which can tolerate heat better than other plastics and resist fire. It is used for making floor tiles,unbreakable kitchenware,ashtray and fire resistant fabric. Special plastic cookware made of melamine is used in microwave ovens for cooking food.
Match column I with column II and select the correct answer from the codes given below.
The correct option is Option B.
The types that resemble silk are often called artificial silk. It is obtained by chemical treatment of wood pulp of cotton. The fibre is used to make textiles for clothing and other purposes. Rayon production involves solubilizing cellulose.
Spandex, Lycra or elastane is a synthetic fiber known for its exceptional elasticity. It is a polyether-polyurea copolymer that was invented in 1958 by chemist Joseph Shivers at DuPont's Benger Laboratory in Waynesboro, Virginia.
Acrylic fiber is a synthetic fiber that closely resembles wool in its character. Acrylic fiber is a synthetic fiber that closely resembles wool in its character. It can be used 100% alone, or in blends with other natural and synthetic fibers.
Nylon, the first synthetic fiber in the "fully synthetic" sense of that term, was developed by Wallace Carothers, an American researcher at the chemical firm DuPont in the 1930s. It soon made its debut in the United States as a replacement for silk, just in time for the introduction of rationing during World War II.
Which of the following materials is the best for making garments and jackets that can be used in wet or damp environment?
Polyester is a water-resistant synthetic fibre which makes it ideal for making garments and jackets that are to be used in wet or damp environment.
Match column I with column II and mark the correct option from the codes given below.
The correct option is B.
The permanent press or perma press setting is basically for polyester fabrics. ... The warm air dries the garments, but the cool air "sets" the garment, so it resists wrinkles.
The modern non-stick pans were made using a coating of Teflon (polytetrafluoroethylene or PTFE). PTFE was invented serendipitously by Roy Plunkett in 1938, while working for a joint venture of the DuPont company.
Rayon is made from cellulose obtained from wood pulp–usually from pine, spruce, or hemlock trees—and cotton linters, which are residue fibres clinging to cotton seed after the ginning process.
Nylon has since become a popular choice, as it has excellent wind resistance, good elasticity, mildew resistance, and is comparatively cheaper. ... Nylon fabric for parachutes is woven in a specialized manner with extra thick threads to create a pattern of small squares – this is known as ripstop nylon.
Choose the correct option for the given statements.
Correct Answer :- b
Explanation:- Conduction of heat and electricity requires free electrons. Plastics, whose molecules are made from long combinations of carbon and hydrogen atoms, have few or no free electrons.
Ropes made by nylon are used in cranes and elevators.
Read the given statements and mark the appropriate answer.
Statement 1: Polyester is synthesised from petrochemicals by linking ester units.
Statement 2: Polyester is a natural fibre
The most common type of chemical reaction used to make polyester takes place at high temperatures in a vacuum. A petroleum by-product, alcohol, and carboxyl acid are mixed to form a compound known as monomer or “ester.” This reaction is known as polymerization.
Polyester is a synthetic petroleum-based fibre, and is therefore a non-renewable carbon-intensive resource. Nearly 70 million barrels of oil are used each year to make polyester around the world, which is now the most commonly used fiber in making clothes.
Which of the following is not a characteristic of plastics?
Plastics are inflammable i.e., they burn easily.
See the figure given below and select the correct statements regarding polymers.
1. Figure (X) shows structure of a monomer while figure (Y) shows structure of a polymer.
2. Small boxes in the structure represent monomers which are joined to give a polymer.
3. Figure (X) shows structure of a linear polymer while (Y) shows structure of a cross-linked polymer.
The monomer units of plastics differ in the arrangement, wherein certain cases, they are linear and sometimes cross-linked.
Choose the option containing correct words word to replace P,Q,R and S:
Fibres are materials which are usually thin and have thread-like structure. They are generally classified as P and Q, on the basis of their origin. Natural fibres may be plant fibres like R or animal fibres like S.
The correct option is Option B.
Fibres are materials which are usually thin and have thread-like structure. They are generally classified as Natural and Synthetic, on the basis of their origin. Natural fibres may be plant fibres like cotton or animal fibres like silk.
Sneha has classified a few materials as shown in the table.
The materials which are classified incorrectly are
As a fiber, jute is biodegradable (it degrades biologically in 1 to 2 years) and compostable.
Coir fiber is the natural fiber extracted from the husk of the coconut. The coir fiber is the thickest and most resistant of all commercial natural fibers.
Acrylic is not easily recycled nor is it readily biodegradable.
Hence the correct answer is (c) as they possess incorrect information.
Anisha prepared a flowchart to show classification of fibres and plastics. She left few columns blank. Fill in the blanks by choosing the option with correct words.
B is the correct option.
The fibres which are obtained from natural sources like plants(Q) and animals(P) are called natural fibres. Natural fibres are a collection of tiny threads obtained from plants and animals. For Ex: cotton, wool ,Silk ,flax, jute. Flax and jute are the natural fibres obtained from plants
There are two main types of plastics and these are named Thermoplastics(S) and Thermosetting(R) Plastics. Thermoplastics are made up of lines of molecules with few cross linkages. This allows them to soften when heated and to be bent into a variety of shapes and forms. They become stiff and solid again when cold.
A few polymers are grouped together on the basis of some common property as follows: Group I: Rayon, acrylic, nylon, jute Group II: PVC, melamine, teflon Group III: Polycot, terrywool, acrylic
Choose the odd one out in group I, II and III.
Group I: Jute is a natural fibre while others are synthetic. Group II: Melamine is a thermosetting polymer while others are thermoplastics. Group III: Acrylic is not a blended fibre.
Plastics are generally made from
Read the given passage and fill in the blanks by choosing an appropriate option. Cellulose is a naturally occurring fibre. The walls of i are made of cellulose. It is used in making a synthetic fibre ii which resembles the most expensive natural fibre iii in appearance hence, it is also called iv .
Read the following statements carefully.
P. I am extensively used in the healthcare industry but my one disadvantage is that I am non-biodegradable.
Q. I am very familiar form of polyester and used for making bottles, utensils, films, wires, etc.
R. I am artificial silk and mixed with wool to make carpets. P, Q and R are respectively
The correct answer is D as plastic is non biodegradable , and PET is used for making bottles and rayoon is mixed with wool.
Match column I with column II and choose the correct option from the codes given below.
Nylon after flame burn slowly and melt. They are self-extinguishing but drip dangerously. Their odor is like celery and they leave no ash but the fume is very hazardous with the smell of burning hair.
Wool burns slowly and shrinks or curls away from the flame. Will not stay lit after flame is removed. Very little smoke is produced but it smells like burnt hair (wool) or feathers (silk).
Rayon is a natural fiber made of cellulose, it will burn fast and single quickly with the smell of burning hair.