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PAPER-10th Science Notes


Industrial Inorganic Chemistry


Text Book Question and Answers

I. Fill in the blanks with suitable answer

1. The major natural polymer present in paper is Cellulose.

2. The coating chemical used to coat paper in the final stage of manufacturing paper is Calcium carbonate or china clay

3. Paper turns yellowish with age due to the presence of the chemical Lignin

4. The type of paper used in the separation of mixtures in the laboratory is Filter paper

II. Answer the following questions

1. It is easy to tear the wet paper instead of dry paper. Why?

The tensile strength radically reduces on wetting.

2. Why paper is considered eco-friendly substance?

Since paper is biodegradable it is considered eco-friendly

3. Describe the steps involved in the process of paper making

a. Pulping: the wood is chipped and made into fibres; pulp is bleached before additives are used.

b. Mixing additives: pulps may contain fillers such as chalk or china clay which improve the characteristics of paper.

The pulp is then fed to a paper machine where water is removed from it by pressing and drying and it forms paper web.

c. Drying: this involves using air and heat to remove water from the paper sheet.

d. Finishing: Paper at this point is uncoated which is coated with a thin layer of calcium carbonate or china clay.

4. List any four uses of paper

a. Filter paper is used to separate fine solids from liquids or air.

b. Tissue paper is used as facial tissue napkins and household towels

c. Wax paper is used in wrapping food for storage

d. Card board paper is used in post care, poster and display board drawing.

e. Paper is used for writing and printing.

f. Paper is used in origami and kirigami activities

g. Paper is used for bags

h. Paper is used for cups

5. Paper absorbs water/oil, why?

Since paper is porous it absorbs water/oil


Additional Questions

1. Why does paper yellow with age?

A major component of wood is lignin. In the presence of light and oxygen lignin reacts to give yellow material hence paper yellows with age.

2. Define paper

Paper is a thin material produced by pressing together cellulose pulp derived from wood and drying them into flexible sheets.

3. Why is paper considered as eco-friendly substance?

Paper is made from biodegradable materials such as-wood pulp and fibrous plants. Secondly, paper is easily recyclable. Therefore, paper is an eco-friendly substance.

4. Name the types of paper

a. Filter paper

b. Tissue paper

c. Wax paper

d. Cardboard paper

5. List the steps involved in paper manufacturing

a. Pulping

b. Mixing additives

c. Drying

d. Finishing

6. What is wood pulp?

A fibrous material prepared by separating cellulose fibres from wood or fibre crops is called wood

7. What is meant by pulping with respect to the manufacture of paper?

The process of obtaining a fibrous material from wood chips either through mechanical or chemical means is called pulping

8. What additives are mixed to the wood pulp while making paper? Why is it done? '

Wood pulp is mixed with certain filler materials such as chalk or china clay and other chemicals. This is done to improve the quality of paper for smoother writing or printing

9. How is paper dried during its manufacture?

Paper is pressed in rollers in a huge machine to remove water from it. Then air and heat are used to remove the remaining moisture. The heating is done by using steam drier.

10. What is done at the ‘finishing’ stage of manufacture of paper?

The final stage of making paper is called ‘finishing’. At this stage, the dried paper is wound onto large reels, where it will be further processed depending on its ultimate use. Paper is smoothened and compacted further by passing through heavy metal rollers. A particular finish, whether soft, dull, hard or shiny, is imparted to the paper by these compacting rollers.

The paper is subjected to further finishing by giving a thin coating of calcium carbonate or china clay. Then the paper is cut to the desired size,

11. Explain briefly the process of manufacture of paper.

Paper is made from wood chips. Wood chips are first processed either mechanically or chemically to obtain a fibrous wood pulp. The pulp so obtained is bleached. Suitable additives like chalk or china clay are added to improve the quality of paper. The pulp is then fed into a paper machine where the slurry is pressed into a sheet as water content is squeezed out. The sheet is further pressed to remove leftover water using felt and a series of steam driers. The dried paper is given finishing touch by giving a fine coating of calcium carbonate or china clay. The paper is then cut to the desired size and packed.

12. What are the main limitations of paper?

a. Unlike plastic, they are not perfectly non porous.

b. Their tensile strength radically reduces on wetting

13. Why does the paper turn brittle and yellow with aging?

Paper loses its residual moisture with time. This is why it becomes more brittle with time. Secondly, paper contains fair amount of lignin which reacts with oxygen in the presence of light to give a yellow coloured material. This is why paper turns slightly yellow with aging.

14. Paper absorbs water/oil. Why?

Paper usually contains tiny pores through which water/oil rise by capillary action. .

15. What is filter paper? Mention its properties.

A piece of porous semipermeable paper which is usually used for filtering liquids is called filter paper.

Filter paper is porous. It contains tiny pores all over it. We get filter papers with pores of various sizes,

16. List the uses of filter paper.

Some of the uses of filter paper include the following:

1)It is used to filter tea and coffee.

2)It is used in the laboratory for carrying out chemical filtration.

3) It is used to separate solids from liquids or air,

4) Filter paper impregnated with various reagents is used to carry out certain tests like pH test.

17. What is tissue paper? What is it made from?

A thin, soft, translucent paper used for packing, wrapping, or protecting delicate articles is called tissue paper.

Tissue paper is made from virgin wood pulp or from recycled paper pulp.

18. List some of the uses of tissue paper.

Tissue paper is used to make facial tissue napkins, toilet paper, paper towels, wrapping tissues, table napkins etc.

19. What is wax paper? What is it otherwise called?

Paper that has been made moisture-proof by treatment with wax or paraffin is called wax paper.. Paper is made non-porous by the application of wax or paraffin. Therefore, it is also called paraffin paper.

20. Mention some of the uses of wax paper.

Wax paper is commonly used for wrapping food for storage. It is also used in arts and crafts.

21. What is cardboard paper? Mention some of its uses.

A thick and stiff paper made from wood pulp used especially for making boxes is called cardboard paper.

Cardboard paper is used to make drawing sheets, post card, display boards, paper cartons and packing boxes.

22. State any two limitations of paper when compared to plastic.

Paper, unlike plastic, is porous and hence is not moisture-proof Secondly, the tensile strength of the paper dips radically on wetting.

23. How is wax paper made?

Wax paper is also known as paraffin paper, is made moisture proof through the application of wax which makes paper non-porous.

24. Now a days paper machine use steam heated drier.

25. The tensile strength of paper is decided by its thickness

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