Polymer Chemistry Book Back Questions 7th Science Lesson 16
7th Science Lesson 16
16] Polymer Chemistry
Book Back Questions with Answer and Do You Know Box Content
Do You Know?
Nylon is very strong and can be used for rock climbing! Nylon is a plastic polymer made chemical units called polyamides. Polyamides are made with monomers – hexamethylenediamine and adipic acid. Solid chips of these polyamides are melted and forced through a heated spinneret which has very, very tiny holes.
Synthetic fibres are made from the by-products of processing petroleum oil and gas. You will learn about fractional distillation of petroleum in your higher classes.
It is estimated that every year we use a trillion plastic carry bags (2 million a minute) around the world and out of which only 1 to 3% are recycled.
Plastic has been around for less than 200 years. Edmund Alexander Parkes was the creator of the first plastic called ‘Parkesine’.
We have seen that synthetic clothes are made from plastic. Every time we wash synthetic clothes, small fibres called microfibers escape and end up in the soil, streams, rivers and oceans. Dangerous pollution called Persistent Organic Pollutants (POPs) floating in the ocean sticks to these small pieces of plastic making them toxic. Marine animals such as shrimp and fish often east micro plastics, confusing them for their natural source of food. The toxins build up in these animals and move up the food chain and can end up in our bodies. Micro plastics can be found in the food we eat, the water we drink and the air we breathe.
A recipe for PLA a compostable plastic.
What you need.
i) 1 tablespoon of corn starch.
ii) 1 teaspoon of vegetable glycerine (available at the pharmacy)
iii) 1 teaspoon of vinegar (5% acidity)
iv) 4 Tablespoons of water.
v) Cooking spoon
vi) Cooking pot
vii) Stove
viii) Aluminium foil
Method: Mix the water with the starch in a cooking pot. Add the vinegar and the glycerine. Mix all the ingredients on medium heat. Make sure you continuously stir. The mixture should turn from liquid white into a clear gel. When it begins to bubble, then it is ready and should be taken off the stove. Spread the gel onto the aluminium foil. Let it cool down for one hour. You can then shape the material to form a cup or bowl. Let the article you made cool for another 24 hours before you try and use it.
Choose the best answers:
1. The first man-made fibre is _____________
(a) Nylon
(b) Polyester
(c) Rayon
(d) Cotton
2. Which of the following is the strongest?
(a) Rayon
(b) Nylon
(c) Acrylic
(d) Polyester
3. When you place a natural fibre in a flame it ______________
(a) Melts
(b) Burns
(c) Gets nothing
(d) Explodes
4. A synthetic fibre which has similar properties to wool is ____________
(a) Nylon
(b) Polyester
(c) Acrylic
(d) PVC
5. A good application of plastic is the use of ____________
(a) Blood bags
(b) Plastic cutlery
(c) Plastic straws
(d) Plastic carry bags
6. _______________ is a non-biodegradable material.
(a) Paper
(b) A plastic bottle
(c) Cotton cloth
(d) Wool
7. PET is the acronym for _____________
(a) Polyester
(b) Polyester and Terylene
(c) Polyethylene terephthalate
(d) Polyetheneterylene
Fill in the blanks:
1. _______________ is an example of polyester fabric.
2. ____________ are used to identify different types of plastics.
3. A _______________ is a long chain made up of many repeated small units called monomers.
4. A natural fibre is called ____________
5. A natural fibre obtained by boiling cocoons is called ________________
State true or false. If false, correct the statement:
1. A lot of plastic pollutes our environment.
2. Refuse (avoid) is the best way to manage plastic.
3. It is good to wear clothes made of synthetic fibres while cooking.
4. Degradable plastics break down into tiny pieces called micro-plastics.
5. Cotton is a natural polymer.
Match the following:
A – B
1. Nylon – Thermoplastic
2. PVC – Thermosetting plastic
3. Bakelite – Fibre
4. Teflon – Wood pulp
5. Rayon – Non-stick cookware’s
Arrange in sequence:
1. Mix water, starch, vinegar and glycerine in a cooking pot.
2. Let the article cool for 24 hours before we use it.
3. Shape material to form a cup of bowl.
4. Continuously mix on medium heat until the liquid turns clear.
5. When the liquid begins to bubble it is ready to be taken off the stove.
6. Spread the gel onto aluminium foil and cool.
Complete the analogy:
1. Cotton: natural: Polyester: _______________
2. PLA spoon: compostable: Plastic spoon: ____________
3. Nylon: melts on heating: Silk: _____________
Consider the statements given below and choose the correct option:
1. A: Vegetable peels buried in the soil disappear within two weeks.
R: Vegetable peels are compostable.
2. A: It takes a very long time for nylon clothes to breakdown into microfibers but cotton clothes need only six months to decompose.
R: Nylon made out of petrochemicals is non-biodegradable.
3. A: It is good to avoid plastics.
R: Plastics end up polluting the environment.
Answers:
Choose the correct answers:
1. Rayon 2. Nylon 3. Burns 4. Acrylic 5. Blood bags 6. A plastic material 7. Polyethylene terephthalate
Fill in the blanks:
1. PET water bottles, Soda bottles 2. Resin code 3. Polymer 4. Plant or animal fibres 5. Silk
Say True or False:
1. True
2. True
3. False
Correct Statement: Cotton clothes are good to wear while cooking. Synthetic fibres are not heat resistant and easily catch fire.
4. True
5. True
Match the following:
1. Thermosetting plastic 2. Fibre 3. Thermoplastic 4. Non-stick cookware’s 5. Wood pulp
Arrange in sequence:
1. Mix water, starch, vinegar and glycerine in a cooking pot.
2. Continuously mix on medium heat until the liquid turns clear.
3. When the liquid begins to bubble it is ready to be taken off the stove.
4. Spread the gel onto aluminium foil and cool.
5. Shape material to form a cup of bowl.
6. Let the article cool for 24 hours before we use it.
Complete the Analogy:
1. Artificial 2. Non-Compostable 3. Transfer the heat
Consider the statements given below and choose the correct option:
1. Both A and R is correct and R is the correct explanation of A.
2. Both A and R is correct and R is the correct explanation of A.
3. Both A and R is correct and R is the correct explanation of A.