Green Science 10 Final PDF (2076)

Gas jar Mixture of NH4Cl Stand and Ca(OH)2 CaO Hard glass test tube Bunsen burner 5. What happens when (write with a balanced chemical equation for each): a. Carbon dioxide is passed through lime water for a while. b. Carbon dioxide is passed through lime water for a long time . c. Carbon dioxide reacts with potassium hydroxide. d. A burning magnesium ribbon is inserted in the gas jar containing carbon dioxide gas. e. Ammonia reacts with conc. hydrochloric acid. f. Ammonia is heated with carbon dioxide at about 1500°C. 6. Give reason: a. Carbon dioxide is collected by upward displacement air. b. Carbon dioxide cannot be collected in the gas jar by passing it through water. c. Moist blue litmus is used to test carbon dioxide gas. d. Ammonia is passed through lime tower. e. Ammonia gas is collected by downward displacement of air. f. Ammonia gas cannot be collected in the gas jar by passing it through water. 7. How is urea prepared ? Write with a balanced chemical equation. 8. What is Haber's process? Write down the conditions required for Haber's process. GREEN Science (Chemistry) Book-10 201

Grid-based Exercise 2 Group ‘A’ (Knowledge Type Questions) (1 Mark Each) 1. Name two chemicals which are required to prepare carbon dioxide gas in laboratory. 2. Which gas is obtained by reacting slaked lime and ammonium chloride? 3. Write down the molecular formula and molecular weight of carbon dioxide. 4. What is the percentage of carbon dioxide in atmosphere ? (Ans: 0.03%) 5. Write the molecular formula and molecular weight of ammonia. 6. Write any two physical properties of carbon dioxide gas. 7. What is Haber’s process? 8. Which gas is obtained by reacting limestone and dilute hydrochloric acid? 9. Which gas is used to take out blue print? 10. What happens if ammonia gas is passed into water containing a few drops of phenolphthalein solution ? 11. What happens when carbon dioxide gas is cooled to -78°C ? 12. What is promoter? Give an example of it. 13. Which gas is produced in the chemical reaction of dilute hydrochloric acid and marble pieces ? 14. What is dry ice? 15. Write any two physical properties of ammonia gas. Group ‘B’ (Understanding Type Questions) (2 Marks Each) 16. It is dangerous to clean well remaining closed for a long time, why? 17. Write any two differences between carbon dioxide and ammonia gas. 18. Why is carbon dioxide gas used in fire extinguisher? 19. Ammonia gas cannot be collected in an erect gas jar, why? 20. Lime water turns milky when carbon dioxide gas is passed through it, why ? 21. Carbon dioxide gas can be tested with the help of moist blue litmus paper, why? 22. Which gas is collected in the gas jar laboratory by downward displacement of air ? Why ? 23. Carbon dioxide gas is important for green plants,why? 24. A moist red litmus paper is used for testing ammonia gas, why? 25. Carbon dioxide gas is not collected over water, why? Group ’C’ (Application Type Questions) (3 Marks Each) 26. Draw a neat and labelled figure showing the laboratory preparation of carbon dioxide gas with balanced chemical equation. 27. How is carbon dioxide gas manufactured in industries ? Write with chemical equation. 28. Write any three utilities of carbon dioxide gas. 202 GREEN Science (Chemistry) Book-10

29. How is ammonia gas manufactured in industries ? Explain. 30. Write any three utilities of ammonia gas. 31. Which gas is obtained by heating the mixture of Ammonium chloride and Calcium hydroxide? What happens when glass rod dipped in hydrochloric acid is brought in contact with this gas? Also, write the chemical equation. 32. Draw a neat and labelled figure showing laboratory preparation of ammonia gas with balanced chemical equation. Group ‘D’ (Higher Abilities Type Questions) (4 Marks Each) 33. Answer the questions after observing the given figure: Delivery tube i. Which gas is being collected Dil. hydrochloric acid in the gas jar? Thistle funnel ii. Write an equation for the Gas jar chemical reaction of the gas preparation. Pieces of CaCO3 iii. This gas cannot be collected by downward displacement of water, why? iv. What happens when a burning magnesium ribbon is inserted into the jar containing this gas ? 34. Ammonia gas can be prepared by heating two solid substances in laboratory. Answer the following questions: 2+2 i. Write down the name of two Gas jar solid substances are used in it with their molecular formulae. Mixture of NH4Cl Stand and Ca(OH)2 ii. Draw a well labelled diagram Hard glass test tube CaO of the laboratory preparation Bunsen burner of this gas. 35. Answer the following questions with the help of the given figure. 1 +2+1 i. Which gas preparation does the given figure show ? Gas jar Gas jar ii. Write down a balanced chemical equation involved in it. iii. What substance will be produced when Gas the above gas reacts with water ? Write the Marble chemical equation. GREEN Science (Chemistry) Book-10 203

UNIT Metals 11 Weighting Distribution Theory : 7 Practical: 1 Before You Begin Scientists have discovered 118 elements so far. Among them, most elements are metals. The elements that form electropositive ions (except hydrogen) and conduct heat and electricity are called metals. They are very useful for human beings. Metals are being used by human beings from ancient time. Metals are malleable and ductile. They are good conductor of heat and electricity. They are shiny and lustrous. Most metals are hard and exist in solid state. Metals are used for making construction materials, cooking utensils, automobiles, ornaments, electric wires, coins, equipment, weapon and so on. In this unit, we will study some common metals (iron, aluminium, copper, silver and gold), their occurrence in nature physical properties and uses in brief. Learning Objectives Syllabus After completing the study of this unit, students will be able to: i. explain the metals (iron, aluminium, copper, silver • Introduction to metals • Some important metals and gold) and their occurrence in nature. – Iron – Aluminium ii. state physical properties of above given metals. – Copper – Silver iii. explain the uses of above given metals – Gold • Physical properties and uses of metals Glossary: A dictionary of scientific/technical terms metals : electropositive elements which conduct heat and electricity malleability : the property of a body by virtue of which it can be beaten into a thin sheet ductility : the property of a body by virtue of which it can be drawn into a long wire ore : the mineral from which a metal can be extracted for commercial purpose minerals : those naturally occurring substances that contain metals in more or less lustrous amount lustre : having lustre; shining : the shine from the surface of a mineral 204 GREEN Science (Chemistry) Book-10

Some Important Metals 1. Iron Iron is an abundant metal found on the earth's crust. In Latin language, iron is called ferrum. So the symbol of iron is 'Fe'. The atomic number of iron is 26 and its atomic weight is 56. The electronic configuration of iron is given below: Shell K L M N No. of electrons 2 8 14 2 Orbital 1s² 2s² 2p6 3s² 3p6 3d6 4s² Position of iron in Modern Periodic table Iron belongs to d-Block, group 8 and 4th period of Modern periodic table. The valency of iron is 2 or 3. The outermost s-sub-shell of iron consists of 2 electrons. So the position of iron should be in group 2 but it is placed in group 8 of the modern periodic table because it is a transitional metal. The properties of iron differ from those of normal elements. Iron forms ferrous ion (Fe++) by losing two electrons and ferric ion (Fe+++) by losing three electrons. Occurrence and Ores of Iron Iron is found in very less amounts in free state in nature as it is a reactive element. Iron is found in the from of ores in nature. Very less amount of iron is found in the body of living beings. It is found in blood in the form of haemoglobin. The main ores of iron are haematite Do You Know (Fe2O3), magnetite (Fe3O4), limonite (Fe2O3.3H2O)iron pyrite (FeS2) and Ores are the minerals from which metals can siderite (Fe CO3). Haematite is the be extracted in a large amount for commercial principal ore of iron. It consists of purpose, e.g. haematite, bauxite, etc. about 72.5% iron. Generally, iron is extracted from haematite ore as it is abundant on the earth's crust. Fig. 11.1 Magnetite ore Iron pyrite ore Siderite ore Haematite ore Physical properties of iron 1. Pure iron is an ash coloured grey white metal. 2. It is good conductor of heat and electricity. GREEN Science (Chemistry) Book-10 205

3. It is malleable and ductile. 4. Its specific gravity is 7.86. 5. Iron melts at 1500° C and boils at 2500° C. 6. Iron loses magnetic properties when heated above 770° C. Uses of Iron 1. Iron is used for manufacturing building materials like rods, pipes, wires and machinery parts. 2. It is used for making parts of vehicles, railway tracks, etc. 3. It is used for making nails, nuts and bolts and household utensils. 4. It is used for making cooking utensils and agricultural tools. 5. It is used for making weapons and different types of tools. 6. It is used in various chemical reactions as a catalyst. 7. It is used to manufacture steel. Fig. 11.2 Weapon made of iron Cooking utensils made of iron Construction of building using iron rods 2. Aluminium Aluminium is an abundant metal found on the earth's crust. Its symbol is Al. Its atomic number is 13 and atomic weight is 27. The electronic configuration of aluminium is given below: Shell K L M No. of electrons 2 8 3 Orbitals 1s² 2s² 2p6 3s² 3p1 Position of Aluminium in Modern Periodic Table The outermost shell of aluminium consists of three electrons. So it is kept in group 13 of modern periodic table. It is kept in p-Block and 3rd period of modern periodic table. 206 GREEN Science (Chemistry) Book-10

Aluminium loses three electrons from the valence shell and forms aluminium ion (Al+++). The valency of aluminium in 3. Occurrence and ores of aluminium Aluminium is a highly reactive metal. So it is not found in free state in nature. It is found in the form of compounds and ores in nature. The main ores of aluminium are: i. Bauxite (Al2 O3. 2H2O) ii. Feldspar (KAlSi3O8) iii. Cryolite (Na3AlF6) iv. Kaolin (Al2Si2O7.2H2O) Bauxite is the principal ore of aluminium. Therefore, aluminium is generally extracted from this ore. Fig. 11.3 Cryolite Feldspar Bauxite Physical properties of aluminium 1. Aluminium is a shiny and silvery-white colured metal. 2. It is good conductor of heat and electricity. 3. It is highly malleable and ductile. 4. Its specific gravity is 2.7. 5. It melts at about 660°C and boils at about 1800°C. 6. It is very light and strong metal. Used of Aluminium 1. Aluminium is used for making cooking utensils due to its light weight and rust free nature. 2. It is used for making bodies and parts of aeroplane, ship, car, motorcycle, etc. 3. It is used for making electric wires, photo frames, etc. 4. It is used for making materials for construction like windows, doors, roofs, etc. 5. It is used for making silver paint by mixing its powder with oil. GREEN Science (Chemistry) Book-10 207

6. It is used for making aluminium foil for packaging medicines, chocolates, etc. and packing foods. 7. It is used for making coins and alloys. 8. It is used for making overhead electric cables. Fig. 11.4 Parts of aeroplane made of Aluminium foil Utensils made of aluminium aluminium 3. Copper Copper is a reddish-brown shiny metal. Its Latin name is cuprum. So its symbol is Cu. The atomic number of copper is 29 and its atomic weight is 63.57. The electronic configuration of copper is given below: Shell K L M N No. of electrons 2 8 18 1 Orbital 1s² 2s² 2p6 3s² 3p6 3d10 4s1 Position of copper in modern periodic table Copper has one electron in its outermost shell. So it is placed in group 11 of the modern periodic table. It belongs to d-Block and 4th period of the modern periodic table. Its valency is 1 or 2. It forms cuprous ion (Cu+) by losing one electron and cupric ion (Cu++) by losing two electrons from the valence shell. Occurrence and ores Copper is found in pure as well as in combined state in nature. The main ores of copper are: i. Copper pyrite or chalcopyrite (CuFeS2) [Principal ore] ii. Chalcocite (Cu2S) or copper glance and iii. Cuprite (Cu2O). iv. Malachite [Cu(OH)2.CuCO3] v. Azurite [Cu(OH)2.2CuCO3] Copper is generally extracted from copper pyrite or chaolcopyrite. 208 GREEN Science (Chemistry) Book-10

Fig. Fig.11.5 Chalcocite ore Cuprite ore Chalcopyrite ore Physical properties of Copper 1. Copper is a shiny reddish - brown metal. 2. It is a very good conductor of heat and electricity. 3. It is highly malleable and ductile. 4. Its specific gravity is 8.95. 5. It melts at about 1083°C and boils at about 2350°C. 6. It is soft in nature. Uses of Copper 1. Copper is used for making household utensils. 2. It is used for making electric wires, electric motor, dynamo and other electric and electronic appliances. 3. It is used for making steam pipe, vacuum pan and calorimeter. 4. It is used for electroplating 5. It is used for making coins. 6. It is used for making various chemicals, insecticides, germicides and fungicides. 7. It is used in electrotyping. 8. It is used for making alloys like brass, bronze, bell metal, etc. 11.6 Coins of Copper Copper wire Utensils made of Copper GREEN Science (Chemistry) Book-10 209

Copper is used in different alloys. Some of the alloys with their composition and uses are given below: i. Brass : Brass is the mixture of copper and zinc. It Fig. Fig. is used to make nutbolts, medals, condenser tube and household utensils. 11.7 Brass utensil ii. Bronze: It is the mixture of copper, tin and zinc. It is used for making coins and household utensils. 11.8 Bronze utensil iii. German silver: It is the mixture of copper, zinc and Fig. nickel. It is used for making bells and household utensils. 11.9 German silver iv. Bell metal: It is the mixture of copper and tin. It is Fig. Fig. used for making bells and decorative items. 11.10 Bell metal v. Gun metal: It is the mixture of copper, tin, zinc and lead. It is used for making ball bearings and parts of machines. 11.11 Gun metal wheel 210 GREEN Science (Chemistry) Book-10

4. Silver Silver is a shiny white metal. Its Latin name is Argentum. So its symbol is Ag. The atomic number of silver is 47 and atomic weight is 107.9. The electronic configuration of silver is given below: Shell K L M N O No. of electrons 2 8 18 18 1 Orbitals 1s2 2s² 2p6 3s² 3p6 3d10 4s² 4p6 3d10 5s1 Position of Silver in Modern Periodic Table The outermost shell of silver consists of only one electron. So it is kept in group 11 of Modern Periodic table. It is placed in d-Blcok and 5th period of modern periodic table. The valency of silver is 1. It forms silver ion (Ag+) by losing one electron form its valence shell. Occurrence and Ores of silver Silver is a less reactive metal. So it is found in free as well as combined state in nature. It is found in the from of ores. The main ores of silver are argentite or silver glance (Ag2S), Silver copper glance [(AgCu2)2S], horn silver (Ag Cl), Ruby Silver (Pyrargylite) [Ag2Sb2S3,] etc. The principal ore of silver is argentite. Fig. 11.12 Horn silver Silver Copper Glance Argentite ore Physical properties of silver 1. Silver is a shiny white metal. 2. It is a very good conductor of heat and electricity. 3. It is highly malleable and ductile. 4. Its specific gravity is 10.5. 5. It melts at about 960° C and boils at about 1955° C. Uses of silver 1. Silver is used for electroplating. 2. It is used for making coins, decorative items, idols, satues, etc. GREEN Science (Chemistry) Book-10 211

3. It is used for making medals and ornaments. 4. It is used for shining mirrors. 5. It is used for making ornaments and idols. 6. It is used for making medicines and silver salts. 7. It is used in photography in the form of silver bromide in the negative of a photograph and x-rays. 8. It is used for filling teeth as silver amalgam. 9. Silver is used for making watch, hearing equipment and battery of calculator. 10. It is used for making solar panel. 11. It is used in water purifiers to prevent algae and bacteria from growing in the filters. 12. Silver nitrate is used as a laboratory reagent. 5. Gold Gold is a shiny yellow metal. It is a very expensive metal which is used for making jeweleries and medals. The Latin name of gold is Aurum. So its symbol is Au. The atomic number of gold is 79 and its atomic weight is 197.2. The electronic configuration of gold is given below: Shell K L M N O P No. of electrons 2 8 18 32 18 1 Orbitals 1s² 2s² 2p6 3s² 3p6 3d10 4s² 4p6 3d104f14 5s2 5p6 5d10 6s1 Position of gold in modern periodic table The outermost shell of gold atom consists on only one electron. So, it is kept in group 11 of modern periodic table. Gold belongs to d-block and 6th period of modern periodic table. Its valency may be 1 or 3. Gold forms aurous ion (Au+) by losing one electron and auric ion (Au+++) by losing three electrons. Occurrence of Gold Gold is a very less reactive or noble metal. So, it is mostly found in free state in nature. Gold is found in sandy alluvial soil and quartz veins (reef gold). It is also found in sulphide, oxide, carbonate, sulphate ores. Gold is generally extracted from sandy alluvial soil and calaverite (Au Te2.). 212 GREEN Science (Chemistry) Book-10

11.13Fig. Fig. Calaverite Sandy alluvial soil rich in gold Physical properties of gold 1. Gold is a soft and bright-yellow metal. 2. It is a very good conductor of heat and electricity. 3. It is a very less reactive metal. 4. Its specific gravity is 19.3. 5. It melts at about 1063°C and boils at about 2530°C. Uses of gold 1. Gold is widely used for making jeweleries, statues and other ornaments. 2. It is used for making medals and idols of god. 3. It is used for making coins. 4. It is used for electroplating. 5. It is used in photography and dentistry. 6. It is used for making anti-inflammatory medicines. 7. It is used for making alloys. 8. It is used for making gold leaf electroscope. 9. It is used for making corrosion resistant electrical connectors in computerized devices. 11.14 Gold coins Gold ornaments GREEN Science (Chemistry) Book-10 213

Occurrence of Metals in Nepal S.No. Metals Ores/sources Occurrence (Districts of Nepal) 1. Chalcopyrite Udaypur, Dhading, Makawanpur, 1. Copper Solukhumbu 2. Copper glance 2. Gold 1. Free gold Rapti Mustang 2. Sandy alluvial soil Kathmandu Lalitpur 3. Iron 1. Haematite Bhojpur 2. Magnetite Ramechhap Tanahun 4. Calcium Limestone Chitwan Pyuthan 5. Magnesium Magnesite Makawanpur Dhading 6. Bismuth Bismuth Udaypur Kathamandu 7. Lead Lead deposit Dolakha Udaypur 8. Zinc Zinc deposit Makawanpur 9. Cobalt Cobaltite (Bhimphedi) Lalitupr Rasuwa (Ganesh Himal) Lalitupr Rasuwa (Ganesh Himal) Gulmi Palpa Key Concepts 1. The elements that form electropositive ions (except hydrogen) and conduct heat and electricity are called metals. 2. Iron is an abundant metal found on the earth's crust. In Latin language, iron is called ferrum. So the symbol of iron is 'Fe'. 3. Iron belongs to d-Block, group 8 and 4th period of Modern periodic table. The valency of iron is 2 or 3. 4. The main ores of iron are haematite (Fe2O3), magnetite (Fe3O4), iron pyrite (FeS2) and siderite (Fe CO3). Haematite is the principal ore of iron. 214 GREEN Science (Chemistry) Book-10

5. Ores are the minerals from which metals can be extracted in a large amount, e.g. haematite, bauxite, etc. 6. The outermost shell of aluminium consists of three electrons. So it is kept in group 13 of modern periodic table. It is kept in p-Block and 3rd period of modern periodic table. 7. Aluminium is a light - white colured metal. It is good conductor of heat and electricity. 8. Aluminium is used for making cooking utensils, bodies and parts of aeroplane, ship, car, motorcycle, etc. It is also used for making electric wires, photo frames, etc. 9. Copper is a reddish-brown shiny metal. Its Latin name is cuprum. So its symbol is Cu. 10. Copper is used for making household utensils, electric wires, electric motor, dynamo and other electric and electronic appliances. 11. Brass is the mixture of copper and zinc. It is used to make nutbolts, medals, condenser tube and household utensils. 12. Silver is a shiny white metal. Its Latin name is Argentum. So its symbol is Ag. 13. The outermost shell of silver consists of only one electron. So it is kept in group 11 of Modern Periodic table. It is placed in d-Blcok and 5th period of modern periodic table. 14. Silver is a less reactive metal. So it is found in free as well as combined state in nature. 15. Gold is a shiny yellow metal. It is a very expensive metal which is used for making jeweleries and medals. 16. Gold belongs to d-block and 6th period of modern periodic table. Its valency may be 1 or 3. Gold forms aurous ion (Au+) by losing one electron and auric ion (Au+++) by losing three electrons. 17. Gold is a very less reactive or noble metal. So, it is mostly found in free state in nature. 18. Gold is generally extracted from sandy alluvial soil and calaverite (Au Te2.). 19. Gold is widely used for making jeweleries, medals and idols of god. Sequential General Exercise 1 1. Choose the best answer from the given alternatives. a. What is the atomic weight of iron? 27 26 56 79 b. Which of the following is the principal ore of aluminium? Bauxite Feldspar Cuprite Haematite GREEN Science (Chemistry) Book-10 215

c. Which of the given metals is used to make overhead electric cables? Iron Copper Gold Aluminium d. Which of the given metals is found in free state in nature? Iron Copper Gold Aluminium e. What is the valency of gold? 1 and 2 2 and 3 1 and 3 2 and 4 2. Answer the following questions. a. What are metals? Give any three examples. b. Write any tree properties of metals. c. What are ores? Give any five examples. d. Write down any two ores of each iron, aluminium, copper and silver. e. Why is copper used for making electric wires and cooking utensils? f. Write down the occurrence of iron and aluminium in brief. 3. Write down any three physical properties any three uses of given metals. – Iron – Aluminium – Copper – Silver – Gold 4. Give reason: a. Iron is used for making cooking utensils. b. Aluminium is used for making bodies and parts of aeroplane. c. Gold is found in free state in nature but not iron. d. Gold is used for making jeweleries. 5. Write any four uses of each copper, silver and gold in our daily life. 6. Where is gold found in nature? Write. 7. Name the metals that can be extracted from each of the given ores. – Cuprite – Magnetite – Bauxite – Calaverite – Haematite – Siderite – Chalcopyrite 8. Write a short note on occurrence of metals in Nepal. 216 GREEN Science (Chemistry) Book-10

Grid-based Exercise 2 Group ’A’ (Knowledge Type Questions) (1 Mark Each) 1. Name any two ores of iron. 2. Write any two physical properties of iron. 3. Name the chief ores of aluminium. 4. Write any two physical properties of copper. 5. Where and in which state is gold found in nature ? Write. 6. Which metal is extracted from magnetite ore ? 7. Name the metal that can be obtained from the given ores: i. Pyrolite ii. Haematite 8. Write any two physical properties of gold. 9. Name any two ores of copper. 10. Write any two physical properties of silver. 11. What metal is extracted from Bauxite? 12. In which parts of Nepal are given metals found? Write. i. Magnesium ii. Cobalt 13. Name the metal that can be obtained from the given ores: i. Azurite ii. Cryolite 14. Write any two physical properties of iron. 15. Name the metals which can be extracted from the ores Argentite and Chalcopyrite. Group ’B’ (Understanding Type Questions) (2 Marks Each) 16. Iron is used for making cooking utensils, why? 17. Copper is used for making electric wires, why? 18. Write any two differences between iron and aluminium. 19. Why are iron and aluminium used for making cooking utensils? 20. Write a difference between metal and non-metal on the basis of their density. Why is gold called noble metal ? 21. State any two properties of copper that make it suitable for making pots and pans. 22. The external cover of the aeroplane is made from aluminium instead of iron. Why is it done ? Give two reasons. 23. Gold is found in pure state in nature but not the iron, why ? GREEN Science (Chemistry) Book-10 217

24. Why are gold and silver used for making ornaments? 25. Aluminium is a very reactive metal. Then, why is it that the foods in aluminium pots don’t react with the pots ? Group ‘C’ (Application Type Questions) (3 Marks Each 26. Write any three uses of iron. 27. Write down three uses ot aluminium. 28. What are the uses of copper ? 29. Write any three uses of silver. 30. Write down the main uses of gold. Group ‘D’ (Higher Abilities Type Questions) (4 Marks Each) 31. Write down the electronic configuration of iron and mention the position of iron in the Modern periodic table. 32. Write down the position of silver in periodic table and write a short note on occurrence and ores of silver. 33. Write down the position of copper in periodic table and write a short note on occurrence and ores of copper. 34. Arrange aluminium, iron, gold, silver and copper in the increasing order of their melting points and boiling points. 35. Describe in brief the occurrence of metals in Nepal. 36. Write down the periodic position and electronic configuration (on the basis of sub- shells) of silver and gold. 218 GREEN Science (Chemistry) Book-10

UNIT Hydrocarbon and Its 12 Compounds Weighting Distribution Theory : 4 Practical: 1 Before You Begin A variety of substances are found in our surroundings. Thousands of compounds exist in nature. These compounds can be divided into two types, viz. inorganic compounds and organic compounds. The compounds which are obtained from minerals are called inorganic compounds, e.g. water (H2O), carbon dioxide (CO2), calcium carbonate (CaCO3), magnesium carbonate (MgCO3), etc. The compounds which are obtained from living beings and contain hydrocarbon are called organic compounds. All compounds of carbon except oxide, carbonate, bicarbonate and carbide are called organic compounds, e.g. methane (CH4) propane (C3H8), alcohol, glycerol, ether, etc. Organic compounds consists of hydrogen and carbon. So, they are also called hydrocarbons. Learning Objectives Syllabus After completing the study of this unit, students will be able to: i. introduce hydrocarbons and their types. • Introduction to hydrocarbons ii. state the types of hydrocarbons and define them with • Types of hydrocarbons examples. - Saturated hydrocarbons iii. give general introduction to compounds of hydrocarbons (methane, alcohol, glycerol, sucrose) - Unsaturated hydrocarbons and explain their uses. • Alkanes, alkenes, and alkynes • Homologous series of hydrocarbons • Some hydrocarbons and their compounds – Methane, ethane, propane, butane, alcohol, glycerol, and glucose Glossary: A dictionary of scientific/technical terms hydrocarbons : compounds made of carbon and hydrogen inorganic : obtained from minerals organic : obtained from living beings alcohol : organic compound having hydroxyl (OH) group glycerol : a sweet organic compound having molecular formula C3H5(OH)3 GREEN Science (Chemistry) Book-10 219

Hydrocarbons Compounds like methane (CH4), ethane (C2H6), propane (C3H8), etc. made of two types of elements, i.e. carbon (C) and hydrogen (H). Such types of compounds are called hydrocarbons. The organic compounds made of carbon and hydrogen are called hydrocarbons. Methane (CH4), ethane (C2H6), propane (C3H8), propene (C3H6), methyl alcohol (CH3OH), glycerol [C3H5(OH)3], etc. are some examples of hydrocarbons. Living beings and petroleum products are the main sources of hydrocarbons. Fig. 12.1 Ethane Propane Methane Types of Hydrocarbons Do You Know On the basis of types of bond present The full form of IUPAC is International Union between carbon atoms, hydrocarbons of Pure and Applied Chemistry. This is an are classified into two types. They are organization which suggests us the system of : naming of hydrocarbons. According to IUPAC system of nomenclature, hydrocarbons are named 1. Saturated hydrocarbons with the formula, prefix + word root + suffix. 2. Unsaturated hydrocarbons 1. Saturated hydrocarbons Hydrocarbons like ethane, propane, butane, etc. have a single covalent bond between carbon atoms. Such type of hydrocarbons are called saturated hydrocarbons. The hydrocarbons containing a single covalent bond between two carbon atoms are called saturated hydrocarbons. These hydrocarbons are stable in nature and nothing can be added in these compounds and hence are called saturated hydrocarbons. Saturated hydrocarbons are less reactive. So, they are also called paraffins. Saturated hydrocarbons are commonly known as alkanes. Their general formula is CnH2n+2 where 'n' represents the number of carbon atoms in the given hydrocarbon which may be 1, 2, 3, 4, 5, ……… The first ten members of alkane series (saturated hydrocarbons) with their IUPAC name, molecular formula, condensed formula and structural formula are given below: 1. Methane : CH4 Do You Know Molecular formula H Methane is the smallest known hydrocarbon. It consists of one carbon Structural formula : H C H atom and four hydrogen atoms. H 220 GREEN Science (Chemistry) Book-10

Condensed formula : CH4 H 2. Ethane Molecular formula : C2H6 H Structural formula : H C C H HH H Condensed formula : CH3 – CH3 3. Propane Molecular formula : C3H8 HH Structural formula : H C C C H H HH H Condensed formula : CH3 – CH2 – CH3 4. Butane Molecular formula : C4H10 H HH Structural formula : H C C C C H H HH H H H C Condensed formula : CH3 – CH2 – CH2 – CH3 5. Pentane Molecular formula : C5H12 H HH H Structural formula : H C C C C H HH H H H Condensed formula : CH3 – CH2 – CH2 – CH2 – CH3 6. Hexane Molecular formula : H6H14 H HH HH Structural formula : H C C C C C C H H HH HHH Condensed formula : CH3 – CH2 – CH2 – CH2 – CH2 – CH3 GREEN Science (Chemistry) Book-10 221

7. Heptane Molecular formula : C7H16 H HH H H H H Structural formula : H C C C C C C C H H HH H H H H H Condensed formula : CH3 – CH2 – CH2 – CH2 – CH2 – CH2 –CH3 8. Octane Molecular formula : C8 H18 H HH H H H H H Structural formula : H C C C C C C C C H HH H H H H H H Condensed formula : CH3 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 9. Nonane Molecular formula : C9H20 H HH H H H H H H Structural formula : H C C C C C C C C C H HH H H H H H H Condensed formula : CH3 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 10. Decane Molecular formula : C10H20 H HH H H H H H H H Structural formula : H C C C C C C C C C C H H HH H H H H H H H Condensed formula : CH3 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 2. Unsaturated Hydrocarbons Hydrocarbons like ethene, propene,, butene, etc. have a double covalent bond between any two carbon atoms. Similarly, hydrocarbons like ethyne, propyne, butyne, etc. have a triple covalent bond between any two carbon atoms. Such type of hydrocarbons are called unsaturated hydrocarbons. The hydrocarbons having a double covalent bond or a triple covalent bond between any two carbon atoms are called unsaturated hydrocarbons. Some atoms or molecules can be added in these hydrocarbons. So they are called unsaturated hydrocarbons. The general formula of unsaturated hydrocarbons may be CnH2n or CnH2n – 2. Unsaturated hydrocarbons are unstable in nature. 222 GREEN Science (Chemistry) Book-10

On the basis of type of bond between any two carbon atoms, unsaturated hydrocarbons are of two types. They are as follows: i. Alkenes ii. Alkynes i. Alkenes Hydrocarbons like ethene (H2C = CH2), propene (H2C = CH – CH3), etc. have a double covalent bond between any two carbon atoms. Such types of hydrocarbons are called alkenes. The hydrocarbons having a double covalent bond between any two carbon atoms are called alkenes. Their general formula is CnH2n. Ethene, propene, butene, pentene, etc. are some examples of alkenes. In alkenes, the first member consists of two carbon atoms having a double covalent bond between them. The first nine members of alkene series with their IUPAC name, molecular formula, structural formula and condensed formula are given below: 1. Ethene H Do You Know Molecular formula : C2H4 H Alkenes are also called olefins HH C because they produce oil-like substances. Structural formula : Alkenes are more reactive than HC C alkanes. Condensed formula : H2C = CH2 When alkenes react with sufficient 2. Propene hydrogen, they form alkanes. Molecular formula : C3H6 H The general formula of alkenes is HH CnH2n. Structural formula : H C C H H Condensed formula : H2C = CH – CH3 3. Butene Molecular formula : C4H8 H HH Structural formula : H C C C C H HH H Condensed formula : H2C = CH – CH2 – CH3 4. Pentene Molecular formula : C5H10 H HH H Structural formula : H C C C C C H HHH Condensed formula : H2C = CH – CH2 – CH2 – CH3 GREEN Science (Chemistry) Book-10 223

5. Hexene Molecular formula : C6H12 H HH H H H Structural formula : H C C C C C C H HHHH Condensed formula : H2C = CH – CH2 – CH2 – CH2 – CH3 6. Heptene Molecular formula : C7H14 H HH H H H H Structural formula : H C C C C C C C H HHHHH Condensed formula : H2C = CH – CH2 – CH2 – CH2 – CH2 – CH3 7. Octene Molecular formula : C8H16 H HH H H H H H Structural formula : H C C C C C C C C H HHHHHH Condensed formula : H2C = CH – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 8. Nonene Molecular formula : C9H18 H HH H H H H H H Structural formula : H C C C C C C C C C H HHHHHHH Condensed formula : H2C = CH – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 9. Decene Molecular formula : C10H20 H HH H H H H H H H Structural formula : H C C C C C C C C C C H HHHHHHHH Condensed formula : H2C = CH – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 224 GREEN Science (Chemistry) Book-10

ii. Alkynes Hydrocarbons like ethyne (HC CH), propyne (HC C – CH3), etc. contain a triple covalent between any two carbon atoms. Such type of hydrocarbons are called alkynes. The unsaturated hydrocarbons having a triple covalent bond between any two carbon atoms are called alkynes. Their general formula is CnH2n – 2. Ethyne, propyne, butyne, pentyne, etc. are some examples of alkynes. Alkynes are also called acetylenes because the first member of alkyne series is called acetylene. Alkynes are the most unstable and most reactive hydrocarbons. The first nine members of alkyne series with their IUPAC name, molecular formula, structural formula and condensed formulas are given below: 1. Ethyne Molecular formula : C2H2 Do You Know Structural formula : H C C H Ethyne or acetylene is the smallest Condensed formula : HC CH and the first member of alkyne 2. Propyne series. Molecular formula : C3H4 Alkynes are the most reactive and H unstable hydrocarbons. The general formula of alkynes is CnH2n–2. When alkynes react with sufficient hydrogen they form alkanes. Structural formula : H C C C H Condensed formula : HC H 3. Butyne C – CH3 Molecular formula : C4H6 H H Structural formula : H C C C C H Condensed formula : HC HH 4. Pentyne C – CH2 – CH3 Molecular formula : C5H8 HH H Structural formula : H C C C C C H HHH Condensed formula : HC C – CH2 – CH2 – CH3 GREEN Science (Chemistry) Book-10 225

5. Hexyne Molecular formula : C6H10 HHHH Structural formula : H C C C C C C H Condensed formula : HC HHHH 6. Heptyne C – CH2 – CH2 – CH2 – CH3 Molecular formula : C7H12 HHHH H C Structural formula : H C C C C C C H Condensed formula : HC HHHHH 7. Octyne C – CH2 – CH2 – CH2 – CH2 – CH3 Molecular formula : C8H14 HHHHHH Structural formula : H C C C C C C C C H Condensed formula : HC HHHHHH 8. Nonyne C – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 Molecular formula : C9H16 HHHHHHH Structural formula : H C C C C C C C C C H Condensed formula : HC HHHHHHH 9. Decyne C – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 Molecular formula : C10H18 HHHHHHHH Structural formula : H C C C C C C C C C C H HHHHHHHH Condensed formula : HC C – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH2 – CH3 226 GREEN Science (Chemistry) Book-10

Differences between saturated and unsaturated hydrocarbons Saturated hydrocarbons Unsaturated hydrocarbons 1. They have a single covalent bond 1. They have a double or triple covalent between carbon atoms. bond between any carbon atoms. 2. They are stable compounds . 2. They are unstable compounds. 3. They are less reactive. 3. They are more reactive. 4. Their general formula is CnH2n + 2. 4. Their general formula may be CnH2n or CnH2n – 2. Activity 1 Take a chart paper. Write molecular formula, structural formula and condensed formula of the first ten numbers of alkane series and present it in the classroom. Homologous series Chemist studied the properties of hydrocarbons like methane, ethane, propane, butane, pentane, etc. and found that these compounds have similar structure and chemical properties. But the successive compounds differ by – CH2 group. Such a series of organic compounds is called homologous series. The group of organic compounds having similar structures and chemical properties in which the successive compounds differ by – CH2 group is called homologous series. The same general formula is used to denote all the members of a homologous series. Methane, ethane, propane, butane, pentane, hexane, heptane, octane, nonane and decane are the first ten members of alkane series. They are represented by the same general formula. The first five members of homologous series of alcohol are given below: 1. CH3OH (Methanol) 2. CH3CH2OH (Ethanol) 3. CH3CH2CH2OH (Propanol) 4. CH3CH2CH2CH2OH (Butanol) 5. CH3CH2CH2CH2CH2OH (Pentanol) Alkyl radical The group of organic compounds which is formed by removing one hydrogen atom from alkane is called alkyl radical. Examples : methyl radical (CH3+), ethyl radical (C2H5+), propyl radical (C3H7+), etc. Alkyl radical is represented by CnH2n+1. It is denoted by 'R'. CH4 – 1H CH3+ (methyl radical) C2H6 – 1H C2H5+ (ethyl radical) C3H8 – 1H C3H7+ (propyl radical) GREEN Science (Chemistry) Book-10 227

Functional Group Atoms or group of atoms like hydroxyl (– OH), ether (– O –), carboxylic acid (– COOH), etc. determine the chemical properties of hydrocarbons, which are commonly known as functional groups. An atom or group of atoms that determine the chemical properties of a hydrocarbon is called a functional group. Alkyl radicals combine with functional groups and from different types of organic compounds. Some common functional groups and compounds formed by them are given below: Functional group Structure Compounds formed 1. Hydroxyl (– OH) Alcohol 2. Ether (– O –) – OH Ether –O– 3. Carboxylic acid ( – COOH) Acid O C OH IUPAC system The full from of IUPAC system is International Union of Pure and Applied Chemistry. This system was introduced to maintain uniformity in the nomenclature of inorganic and organic compounds throughout the world. On the basis of this system, a compound gets only one name. It helps in understanding of a certain compound by its unique name throughout the world. Nomenclature of Hydrocarbons 1. First of all, the word root of the given hydrocarbon is found by counting the number of carbon atoms in the given hydrocarbon as follows: No. of carbon atoms Word root Notation C=1 Meth – C1 C=2 Eth – C2 C=3 Prop – C3 C=4 But – C4 C=5 Pent – C5 C=6 Hex – C6 C=7 Hept – C7 C=8 Oct – C8 C=9 Non – C9 C = 10 Dec – C10 2. After finding the word root, – ane, – ene or – yne is added after the word root on the basis of type of bond between carbon atoms. It is done as follows: 228 GREEN Science (Chemistry) Book-10

i. If a hydrocarbon has a single covalent bond among all the carbon atoms, – ane is added after the word root. HH HC C H HH \\ No. of carbon atoms = 2 Word root = Eth – Type of bond = single covalent = + ane \\ Name of hydrocarbon = Eth + ane = Ethane ii. If a hydrocarbon has a double covalent bond between any two carbon atoms, – ene is added after the word root. H HH Example: H C C C H H No. of carbon atoms = 3 \\ Word root = Prop – Type of bond between any two carbon atoms = double covalent = + ene \\ Name of hydrocarbon = Prop + ene = Propene iii. If a hydrocarbon contains a triple covalent bond between any two carbon atoms, – yne is added after the word root. Example : HHH HC C C C C H HHH No. of carbon atoms = 5 \\ Word root = Pent Type of bond between any two carbon atoms = triple covalent = + yne \\ Name of the hydrocarbon = Pent + yne = Pentyne GREEN Science (Chemistry) Book-10 229

Some Common Hydrocarbons 1. Methane Methane is the simplest aliphatic hydrocarbon. Its molecular formula is CH4. It is the smallest and first member of alkane series. Molecular formula : CH4 Structural formula Condensed formula: CH4 H HC H H Methane gas is found is marshy places. So, it is also called a marsh gas. It is formed due to decomposition of organic matter. Mathane gas is commonly found above the mineral oil. This gas is found in gobar gas, biogas and sewage gas. Methane gas is colourless, odourless and tasteless. It does not dissolve in water but dissolves in organic solvents like ether, alcohol, etc. Uses of methane 1. Methane gas is used as a source of heat (fuel) for cooking purpose in rural areas. 2. It is used to produce carbon black. Carbon black is used for making colour, paint, shoe polish, ink, etc. 3. It is used in the manufacture of hydrogen gas. 4. It is used for making chloroform and carbon tetrachloride. 5. It is used for making methyl alcohol, formaldehyde, etc. 2. Ethane Ethane is a saturated hydrocarbon having two carbon atoms. It is the second member of alkane series. Its molecular formula is C2H6. Ethane gas is found along with methane in natural gas, coal gas and petroleum mines. Molecular formula : C2H6 Structural formula Condensed formula: CH3 CH3 HH HC C H HH Ethane gas is colourless, odourless and tasteless. It does not dissolve in water but dissolves in organic solvents like ether, alcohol, etc. Uses of ethane gas 1. Ethane gas is used for welding as it produces more heat while burning. 2. It is used as a source of heat for cooking purpose in the form of bio gas. 230 GREEN Science (Chemistry) Book-10

3. It is used for making shoe polish and diethyl ether. 4. It is used for making ethyl alcohol (ethanol). 3. Propane Propane is a saturated hydrocarbon having three carbon atoms. It is the third member of alkane series. Its molecular formula is C3H8. Propane gas is found in natural gas and petroleum mines. This gas is colourless and odourless. It does not dissolve in water but dissolves in organic solvents like ether, alcohol, etc. Molecular formula : C3H8 Structural formula Condensed formula: CH3 CH2 CH3 H HH HC C C H Uses of propane H HH 1. Propane gas is highly inflammable. So it is used as a fuel. 2. It is used for cooling purpose in petroleum industries. 3. It is used for making propyl alcohol and other organic compounds. 4. It is used in gas lighters. 4. Butane Butane is a saturated hydrocarbon having four carbon atoms. It is the fourth member of alkane series. Its molecular formula is C4H10. Butane gas is found in natural gas and petroleum mines. This gas is colourless and odourless. Butane is insoluble in water but soluble in organic solvents like alcohol, ether, etc. Molecular formula : C4H10 Structural formula Condensed formula: CH3 CH2 CH2 CH3 H HHH HC C C C H H HHH Uses of butane 1. Butane gas is used in LPG (liquefied petroleum gas) along with methane because butane gas easily becomes liquid on applying pressure. 2. It is used as a raw material for making synthetic rubber. Isomers and Isomerism Isomers are the organic compounds having similar molecular formula but different structures and properties. Similarly, the existence of two or more organic compounds having the same molecular formula but different structures nad properties is called isomerism. GREEN Science (Chemistry) Book-10 231

For example, Butane (C4H10) shows isomerism. The two isomers of butane are m-butane and iso-butane. H H HHH H CH HH HC C C C H HC C C H H HHH H HH n-butane (C4H10) iso-butane (C4H10) (Straight chain) (Branched chain) Pentane also shows isomerism. The three isomers of Pentane are n-pentane, iso-pentane and neo-pentane. H H HHHH H CH H HH HC C C C C H HC C C C H H HHHH H HHH n-pentane (C5H12) iso-pentane (C5H12) H H CH HH HC C C H HH H HH H neo-pentane (C5H12) Alcohol The organic compound containing hydroxyl group (– OH) is called alcohol. Alcohol is prepared from alkane by replacing one or more hydrogen atom/s by hydroxyl radical/s. The general formula of alcohol is CnH2n+1(OH). The functional group found in an alcohol is hydroxyl (–OH) group. Examples of alcohol 1. Methyl alcohol (CH3 – OH) 232 GREEN Science (Chemistry) Book-10

2. Ethyl aocohol (CH3 – CH2 – OH) 3. Propyl alcohol (CH3 – CH2 – CH2 – OH), etc. On the basis of number of hydroxyl groups, alcohols are of three types. a. Monohydric alcohol b. Dihydric alcohol c. Trihydric alcohol i. Monohydric alcohol It is the alcohol having only one hydroxyl group (–OH). It can be prepared by replacing one hydrogen atom of an alkane by a hydroxyl radical (OH). Examples: Methyl alcohol (CH3OH) Ethyl alcohol (C2H5OH) Propyl alcohol (C3H7OH) The method of formation of monohydric alcohols is given below: HH HC H –H H C OH + OH H H (Methane) (Methyl alcohol or Methanol) HH HH HC C H –H H C C OH + OH HH HH (Ethane) (Ethyl alcohol or ethanol) HH H HH H HC C C H –H H C C C OH + OH HH H HH H (Propane) (Propyl alcohol or propanol) ii. Dihydric alcohol It is the alcohol having two hydroxyl groups (– OH). It can be prepared by replacing two hydrogen atoms of ethane by two hydroxyl (OH) radicals. GREEN Science (Chemistry) Book-10 233

Example : Ethyl glycol HH HH HCC H HC C H –2H OH OH + 2(OH) Ethyl glycol HH (Ethane) iii. Trihydric alcohol It is the hydrocarbon having three hydroxyl groups. It can be prepared by replacing three hydrogen atoms of propane by three hydroxyl (OH) groups. Example : Glycerol HH H HH H HC C C H –3H H C C C H + 3(OH) HH H OH OH OH (Propane) (Glycerol or Glycerine) Some Common Alcohols and their Uses 1. Methyl alcohol Methyl alcohol is a monohydric alcohol. Its IUPAC name is methanol and molecular formula is CH3OH. The structural formula of methyl alcohol is given below: H H C OH H Methyl alcohol is the first member of monohydric alcohol series. It is prepared by replacing one hydrogen atom of methane by one hydroxyl group. HH HC H –H H C OH + OH H H (Methane) (Methyl alcohol) Uses 1. Methyl alcohol is used for making methylated spirit. 2. It is used for making perfume, dyes, colour, medicine, etc. 3. It is used as fuel in spirit lamp as it produces heat without smoke. 4. It is used in dry cleaning. 234 GREEN Science (Chemistry) Book-10

5. It is used to dissolve fat, oil, paint, varnish, etc. 5. It is used for making formaldehyde which is used to make bakelite in plastic industries. 7. It is used for making synthetic fibers. 8. It is used for making methyl chloride. 2. Ethyl alcohol The molecular formula of ethyl alcohol is C2H5OH and condensed formula is CH3CH2OH. It is the second member of monohydric alcohol series. It can be prepared by replacing one hydrogen atom of ethane by one hydroxyl radical. The IUPAC name of ethyl alcohol is ethanol. It is commonly known as drinking alcohol. HH HH HC C H –H H C C OH + OH HH HH (Ethane) (Ethyl alcohol or ethanol) Uses 1. Ethyl alcohol is used as a thermometric liquid in alcohol thermometer. 2. It is used for making hard drinks like whisky, rum, vodka, wine, beer, etc. 3. It is used in biology lab to preserve specimen. 4. It is used in hospitals, clinics, health posts, etc. to clean cuts and wounds. 5. It is used for manufacturing polythene, terylene, soap, colour, paint, etc. 6. It is used as a solvent to dissolve resin, fat, oil, paint, etc. 7. It is used for making chloroform, ether, iodoform, etc. 8. It is used as a fuel. 9. It is used for making medicine. 10. It is used for making synthetic rubber. 3. Glycerol Glycerol is a trihydric alcohol having sweet taste. The word glycerol has been derived from the Geek word 'glyceros' which means sweet in taste. Glycerol is also called glycerine. Glycerol is a thick and colourles liquid having sweet taste. It is soluble in water and alcohol but insoluble in ether. The structural formula of glycerol its given below: HH H HCC C H OH OH OH The IUPAC name of glycerol is propane 1, 2, 3 triol. The molecular formula of glycerol is C3H5 (OH)3. GREEN Science (Chemistry) Book-10 235

Glycerol is prepared by replacing three hydrogen atoms (one from each carbon) by three hydroxyl radicals. HH H HH H HC C C H –3H H C C C H + 3(OH) HH H OH OH OH (Propane) Glycerol Uses 1. Glycerol is used in face creams, lip guards, etc. to prevent skin from cracking. 2. It is used for making printing ink and ink for stamp pads. 3. It is used as a sweetening agent in sweet house, confectioneries, beverages and medicines. 4. It is used for making high quality soap, lotion, cosmetics and shaving creams. 5. It is used for moistening tobacco. 6. It is used for preserving foods and fruits. 7. It is used as a lubricant in watches. 4. Glucose Glucose is a water-soluble white crystalline powder. Its molecular formula is C6H12O6. It is also called dextrose. Glucose is one of the three monosachharides that are used directly by our body to produce ATP (Adenosene triphosphate). Glucose is formed during photosynthesis from water and carbon dioxide in the presence of sunlight and chlorophyll. Similarly, glucose is broken down into water, carbon dioxide and energy during respiration. Glucose can be obtained by hydrolysis of carbohydrates like sugar, milk, cellulose, etc. found in foods and fruits. Glucose is an important source of energy in most organisms, i.e. bacteria to human beings. The taste of glucose is sweet. Glucose is a carbohydrate and monosachharide sugar. Glucose is found in fruits and honey. It helps in transportation of free sugar in the blood of animals. It is used as the main source of energy essential for cells. It also helps to maintain balance in metabolic activities. Glucose is both beneficial and harmful for animals. High sugar level in blood causes swelling of Do You Know different parts of body. On the other hand, low sugar level in blood is also harmful for the body. The word glucose has been derived from Therefore, there should be adequate amount of Greek word 'glukus' which means sweet glucose in our body to live a healthy life. in taste. 236 GREEN Science (Chemistry) Book-10

Activity 2 Take a chart paper and prepare a list of the hydrocarbons that are used in our daily life. Also, mention their uses. Present your work in your class. Key Concepts 1. The compounds which are obtained from living beings and contain hydrocarbon are called organic compounds. 2. The organic compounds made of carbon and hydrogen are called hydrocarbons, e.g. Methane (CH4), ethane (C2H6), propane (C3H8), propane (C3H6). 3. The hydrocarbons containing a single covalent between carbon atoms are called saturated hydrocarbons. 4. Saturated hydrocarbons are less reactive. So, they are also called paraffins. 5. The hydrocarbons having a double covalent bond or a triple covalent bond between any two carbon atoms are called unsaturated hydrocarbons. 6. The group of organic compounds having similar structures and chemical properties in which the successive compounds differ by – CH2 group is called homologous series. 7. The group of organic compounds which is formed by removing one hydrogen atom from alkane is called alkyl radical. 8. An atom or group of atoms that determine the chemical properties of a hydrocarbon is called a functional group. 9. The full from of IUPAC system is International Union of Pure and Applied Chemistry. 10. Ethane is a saturated hydrocarbon having two carbon atoms. Its molecular formula is C2H6. 11. The organic compound containing hydroxyl group (– OH) is called alcohol. Alcohol is prepared from alkane by replacing one or more hydrogen atom/s by hydroxyl radical/s. 12. Ethyl alcohol is used as a thermometric liquid in alcohol thermometer. It is also used for making hard drinks like whiskey, rum, vodka, wine, beer, etc. 13. Glycerol is a thick and colourless liquid having sweet taste. It is soluble in water and alcohol but insoluble in ether. 14. Glucose is a water-soluble white crystalline powder. Its molecular formula is C6H12O6. It is found in fruits and honey. It helps in transportation of free sugar in the blood of animals. GREEN Science (Chemistry) Book-10 237

Sequential General Exercise 1 1. Choose the best answer from the given alternatives. a. Which of the given hydrocarbons is saturated? Propene Propane Propyne Butene b. Which of the following is the general formula of alkene? CnH2n CnH2n + 1 CnH2n+2 CnHn ethanol c. Which of the following is the IUPAC name of drinking alcohol? methanol ethylene ethanol d. Which of the following is the molecular formula is glycerol? C2H5OH C3H5(OH)3 C3H5(OH)2 C2H5(OH)2 e. Which of the given organic compounds is used in face creams and sweets? glycerol alcohol glucose ethane 2. Answer the following questions. a. What is a hydrocarbon? Give any three examples. b. What are the sources of hydrocarbons? c. Name two types of hydrocarbons. d. What are saturated hydrocarbons? Give examples. e. Define alkanes. Write their general formula and five examples. f. What are unsaturated hydrocarbons? Give any five examples. g. Define alkenes with any three examples. h. What are alkynes? Write any four examples. i. Write down the general formula of alkenes and alkynes. j. What is meant by homologous series? Explain with examples. k. Define functional group with any two examples. l. Write down the full from of IUPAC. 3. Write down the molecular formula, structural formula and condensed formula of the given organic compounds: a. ethane b. butane 238 GREEN Science (Chemistry) Book-10

c. ethyne d. propene e. pentane f. pentyne g. octane h. octene i. acetylene j. ethyl alcohol 4. Write down the molecular formula, source, two features and two uses of a. methane b. ethane c. propane d. butane 5. What is alcohol? Write down the general formula of alcohol. 6. How is alcohol prepared? Write with examples. 7. Name three types of alcohol with one example of each. 8. Write down the structural formula and three uses of methyl alcohol. 9. Write down the structural formula and three uses of ethyl alcohol. 10. What is glycerol? Write its structural formula and three uses. 11. What is glucose? Write down its molecular formula and use in the body. 12. Why is glucose necessary for our body? 13. Give reason: a. Alkanes are called saturated hydrocarbons. b. Alkenes and alkynes are called unsaturated hydrocarbons. c. Alkenes are also called paraffins. d. Alkynes are called acetylenes. e. Methanol is called monohydric alcohol. f. Glycerol is called trihydric alcohol. 14. Differentiable between: a. Saturated hydrocarbons and Unsaturated hydrocarbons b. Alkanes and Alkenes c. Alkenes and Alkynes d. Butane and Butyne e. Ethane and Ethyne f. Monohydric alcohol and Trihydric alcohol 15. Name the given hydrocarbons. H C CH a. H b. H C OH H GREEN Science (Chemistry) Book-10 239

c. H H H d. HH H HC C C H HCC C H H OH OH OH e. HH H C C OH HH 16. Name any two organic compounds that are used at our homes. Also, write down the main use of each. Grid-based Exercise 2 (1 Mark Each) Group ‘A’ (Knowledge Type Questions) 1. What is a hydrocarbon ? 2. How many types of hydrocarbon are there ? Write them. 3. What is the full form of IUPAC ? 4. Where is propane gas found ? 5. What are isomers ? 6. Write down the structural formula of butane. 7. What is glycerol ? 8. Write any two properties of glycerol. 9. What is glucose? 10. Write the molecular formula of glucose. 11. What type of hydrocarbons are called paraffins ? 12. Define unsaturated hydrocarbon. 13. Name the hydrocarbon which is used to make chloroform. 14. Draw structural formula of ethyl alcohol. 15. What is homologous series ? Group ’B’ (Understanding Type Questions) (2 Marks Each) 16. Write any two differences between saturated hydrocarbon and unsaturated hydrocarbon. 17. Butane is called a saturated hydrocarbon, why? 18. Propene is called an unsaturated hydrocarbon, why? 19. Glucose is both useful as well harmful for animals. Justify this statement. 240 GREEN Science (Chemistry) Book-10

20. Write any two differences between Propane and Propyne. 21. What type of hydrocarbon is called an unsaturated hydrocarbon? Write with one example. 22. What is isomerism ? Write with an example. 23. Methane is called a hydrocarbon, why? 24. Acetylene is an unsaturated hydrocarbon. Write down its cause on the basis of its structural formula. 25. What happens when the amount of glucose becomes more or less than the required amount in human blood? Group ‘C’ (Application Type Questions) (3 Marks Each) 26. Write any three uses of methane gas. HH 27. Write the name and three uses of the compound whose structural H C C OH formula is given alongside: HH 28. Write down three uses of glycerine. 29. Write any three uses of ethyl alcohol. OH OH OH 30. Write down the name and two uses of given compound. HC C CH H HH Group ‘D’ (Higher Abilities Type Questions) (4 Marks Each) 31. What are the compounds having the following structural formula? Write the type of hydrocarbon on the basis of bond. Write with reason. i. H H ii. H H H HC C C H C C C OH HHH 32. Mention the method of naming hydrocarbons. 33. Is the given hydrocarbon saturated or unsaturated? H H Name the compound formed by the reaction of above H C C C C H compound with sufficient hydrogen. Also, give one use H HHH of that compound. 34. What are the compounds of the following structural formula ? Write the type of hydrocarbon on the basis of the bond. Write with reason. i. H H H ii. H – C = C – H HC C C H H HH 35. Write the name of compound and its structural formula which is formed by displacement of three hydrogen atom with three hydroxide radical from propane through various chemical reactions. Write a short note on glucose. GREEN Science (Chemistry) Book-10 241

UNIT Materials Used 13 in Daily Life Weighting Distribution Theory : 10 Practical: 0 Before You Begin Chemistry is the branch of science in which we study about different types of chemical substances. Among many branches of chemistry, industrial chemistry is one of them. In industrial chemistry, we study about formation, characteristics and use of chemicals that are used in our daily life. We use a variety of materials like cement, glass, ceramics, plastics, soap, detergent, insecticides, etc. in our daily life. In this unit, we will study some common materials of daily use and chemical pollution in brief. Similarly, we will study the ways to get rid of chemical pollution and solid waste management. Learning Objectives Syllabus After completing the study of this unit, students will be able to: • Cement and uses of cement i. introduce cement, glass, ceramics, plastics, soap and • Glass and its types • Ceramics detergent and to explain their utilities. • Plastics • Soap and detergent ii. explain the role of compost manure in agriculture. • Fertilizers (compost fertilizer iii. describe chemical pollution caused by plastics, and chemical fertilizers) chemical fertilizers, synthetic fibers, colours and • Chemical pollution insecticides. • Ways to get rid of chemical iv. analyze the chemical pollution caused due to over use pollution of chemical fertilizers. • Solid waste management v. identify, demonstrate and utilize biodegradable and non-biodegradable wastes. Glossary: A dictionary of scientific/technical terms cement : a fine gray powder which sets hard when mixed with water and is dried ceramics : the hydrated alumina silica used for making cups, plates, dishes, etc. biodgradable : which decomposes due to action of microbes non-biodegradable : which does not decompose due to action of microbes insecticide : the chemical substances which are used to kill insects fertilizers : the substances that are used to increase the fertility of soil water proof : which does not allow water to enter through it paste : a soft, wet mixture of usually a powder and a liquid 242 GREEN Science (Chemistry) Book-10

Materials used in daily life Cement Cement is a fine gray powder made by Fig. Fig.13.1 grinding limestone (CaCO3) and special type of clay (Al2O3.SiO2). It is used in Cement various construction works. When cement is mixed with sand and water and allowed to set, it becomes as hard as stone. In Nepal, production of cement was started in 1976 AD by Hetauda cement factory. The production of cement was started in England in 1825 AD, Germany in 1855 AD, Belgium in 1855 AD, USA in 1972 AD and India in 1904 AD. The raw materials which are essential for production of cement are as follows: i. Limestone (CaCO3) ii. Special type of clay (Al2O3.SiO2) Manufacture of cement Crushing, grinding and finish grinding are the three steps involved in the manufacture of cement. First of all, limestone pieces are grinded in a grinder to get the pieces of about 2cm. Then the crushed limestone pieces are mixed with clay in ratio 2:1. Then the mixture is again ground to obtain fine powder which is mixed with water to form cement slurry. The cement slurry is passed through a tall rotary kiln. Inside the kiln, cement 13.2 slurry is heated at 1400°C to 1600°C. Rotary kiln for making cement At this high temperature, chemical reaction takes place. As a result, cement clinker is obtained in the form of marble-sized balls. The cement clinker is allowed to cool and is mixed with 2 to 5% of gypsum. Then the mixture is ground to obtain fine powder of cement. Then the cement is packed in air-proof sacks and transported for storage. The chemical reaction involved in manufacture of cement is given below: Limestone + Aluminium oxide + Silicon dioxide Calcium silicate + Calcium aluminate CaCO3 + Al2O3 + SiO2 CaSiO3 + CaAl2O3 Cement GREEN Science (Chemistry) Book-10 243

Uses of cement 1. Cement is used for making mortar which Do You Know is used for joining bricks, plastering walls, roofs, etc. Mortar is the mixture of cement, sand and water. 2. Cement is used for making concrete by mixing cement, sand, water and gravel Gypsum is added to the cement to (pebbles). Concrete is used for flooring increase the setting time of cement and roofing. It is also used for making when mixed with water. walls and pillars. 3. Cement is used for making RCC (Reinforced Cement Concrete). It is a mixture of cement, gravel, sand and water in an iron framework. It is used for making framework of houses and buildings, gutters, tunnel, bridges, etc. Fig.13.3Concrete RCC Fig. Mortar Glass Glass is a solid and transparent industrial material. It is a super-cooled liquid because it flows downwards very slowly. Glass is a homogeneous mixture of alkali metals and alkaline earthmetals. The main raw material of glass is silica which is found in sand. Different types of glasses are used in our daily life. We prepare glass by heating the mixture of silica, sodium carbonate 13.4 and potassium carbonate. As a result, Silica glass silicates are formed. Actually, glasses are silicates of metals. Glass neither exists in solid state nor in liquid state. So, it is considered as the fourth state of matter. Silica glass or Quartz glass When silica is heated at about 1600°C, it melts. When it is cooled it forms a crystalline substance which is known as crystalline glass or silica glass. Pure silica (SiO2) 1600°C Quartz glass 244 GREEN Science (Chemistry) Book-10

Silica glass does not react with acid, water and other chemical substances. This glass has flexibility. So there is no effect of change in temperature in this glass. Silica glass is used to prepare glass glue, laboratory equipment and electrical equipment. Water glass Water glass is prepared by heating silica with sodium carbonate or potassium carbonate at about 800°C. Actually, water glass is a sodium silicate or potassium silicate. The chemical reaction involved in preparation of water glass is given below: SiO2 + Na2CO3 800°C Na2SiO3 + CO2 SiO2 + K2CO3 800°C K2SiO3 + CO2 Water glass dissolves in water. So it is called water glass. This glass is used for making silica garden, fire proof materials, glass paste and gum. Ordinary glass or Soda lime glass Ordinary glass is the glass which is prepared by heating silica with sodium carbonate and calcium carbonate. When the mixture of silica (50%), sodium carbonate (15%), calcium carbonate (10%) and glass pieces (25%) is heated at about 850°C in a tank furnace, ordinary glass is obtained. 2SiO2 + Na2CO3 + CaCO3 850°C Na2SiO3.CaSiO3 + 2CO2 (Sodium Silicate and Calcium Silicate) The liquid state of ordinary glass is poured into containers of various shapes through iron pipe to make various materials. Then these materials are allowed to cool. This process is called annealing. The glass materials become fragile without annealing. Ordinary glass does not dissolve in water. This glass melts at low temperature. So it is called soft glass. It is also called soda lime glass due to its composition. Ordinary glass or soda lime glass is used for making: i. window panes, bottles, light pipes and light bulbs. ii. lens and prism. iii. glass sheets and laboratory apparatus. Hard glass The glass which is prepared by heating silica with potassium carbonate and calcium carbonate is called hard glass. It is also called potash-lime glass because it is made by using potassium carbonate. 2SiO2 + K2CO3 + CaCO3 D K2SiO3.CaSiO3 + 2CO2 (Potassium silicate and Calcium silicate) GREEN Science (Chemistry) Book-10 245

The melting point of hard glass is very high and hence can withstand very high temperature. Therefore, hard glass is used to prepare electric bulb, tube light and laboratory equipment like hard glass test tube, beaker, round bottom flask, etc. which are used at high temperature. Borosilicate glass The glass which is prepared by heating silica with sodium carbonate, calcium carbonate and boric oxide is called borosilicate glass. It is very hard. So, it does not break easily. This glass is also called pyrex glass. 5SiO2 + Na2CO3 + CaCO3 + B2O3 D Na2SiO3.CaSiO3.B2(SiO)3 + 2CO2 (Sodium cilicate.Calcium silicate.Boron silicate) The effect of increase or decrease in temperature is very less in this glass due to presence of boric oxide. This glass does not react with water and acids. Borosilicate glass is used for making test tube, condenser, beaker, flasks, ovenware, ampoules, etc. due to its resistance to heat and chemicals. Lead crystal glass The glass which is prepared by heating silica with potassium carbonate and lead monoxide is called lead crystal glass. It is the homogeneous mixture of potassium silicate and lead silicate. 2SiO2 + K2CO3 + PbO D K2SiO3.PbSiO3 + CO2 (Potassium silicate and lead silicate) It is also called flute glass. The refractive index of this glass is very high due to presence of lead. Therefore, this glass is used for making lens, prism, radar tube, electric bulbs, TV screens, spectacles, expensive drinking glass, etc. It is also used to cut UV-radiation. Coloured glasses We can find the glasses of different colour in market. Coloured glasses are prepared by adding certain metal oxides in the mixture during the preparation of glasses. Some metal oxides and the colour obtained in glass are mentioned below: Colour obtained in glass Metal oxide to be added Blue Cobalt oxide White Tin oxide Red Copper oxide Black Nickel oxide Violet Manganese oxide Yellow/brown Iron oxide Green Chromium oxide Coloured glasses are used for making window panes, spectacles, glasses of car, train, aeroplane, etc. They are also used for making decorative items. 246 GREEN Science (Chemistry) Book-10

A brief account of different types of glasses and compounds found in them is given below: Types of glass Compounds found 1. Silica glass 2. Water glass Silica 3. Ordinary glass Silica and sodium carbonate or silica and potassium carbonate 4. Borosilicate glass Silica (50%), sodium carbonate (15%), 5. Hard glass calcium carbonate and glass pieces (25%) 6. Lead crystal glass Silica, sodium carbonate, calcium carbonate and boric oxide Silica, potassium carbonate and calcium carbonate Silica, potassium carbonate and lead monoxide Ceramics The special type of clay which consists of compounds of carbon, nitrogen, oxygen and silica is called ceramics. It consists of hydrated aluminium silicate. It may contain carbonates of calcium and magnesium and iron oxide. The word ceramics has been derived Fig. from the Greek word 'keramos' which means potter's clay. Ceramics is used for 13.5 making cups, plates, crucibles, mortars, tiles, bricks, etc. The clay which is used Ceramic cups to make white ceramics is called kaolin. To make ceramic utensils, special type of clay is collected, crushed and ground. Then it is sieved to obtain fine powder. Then it is mixed with water to make paste. The paste is cast into different materials (cup, plate, mortar, etc.) and these materials are dried in the sunlight. Then these materials are heated in a kiln at high temperature. As a result, the clay becomes hard and porous. Salt is added to make ceramic materials shiny and attractive. These materials are again heated by applying tin oxide or lead oxide. This process is called glazing. Glazing makes ceramic materials shiny, smooth, attractive and non-porous (water-proof). We can polish the ceramic materials to make them more attractive. Ceramic materials do not react with acid, base and water. They are not affected by increase on decrease in temperature. They are bad conductors of heat and electricity. They do not absorb water. Ceramics is used for making cups, bowls, plates, etc. It is used for making false teeth and bones. It is used for making bricks and tiles. It is used for making mortar and porcelain basin. GREEN Science (Chemistry) Book-10 247

Plastics The man-made polymers which can be changed into various shapes are called plastics. They are made by heating monomers like ethene, vinyl chloride, etc. The word plastic has been derived from a Greek word 'plastico' which means 'capacity to change shape'. All plastics contain numerous monomers connected together due to chemical process. When monomers are heated, they combine and form a long chain called polymer. The process of formation of polymer is called polymerization. H HH H H HH H ...... + C = C + C = C + ...... Polymerization – C – C – C – C – H HH H H HH H Monomers Polymer Types of plastics There are two types of plastics. They are as follows: 1. Thermoplastic 2. Thermosetting plastic 1. Thermoplastic The plastic which becomes soft and flexible on heating and hard on cooling is called thermoplastic. The molecules of this plastic are connected in the form of linear polymer. Therefore, it can be Fig. Fig. changed into various shapes. Examples: Polythene, polysterine, polyvinyl 13.6 chloride (PVC), etc. PVC, Polythene 2. Thermosetting plastic The plastic which becomes hard on heating and cannot be changed into different shapes is called thermosetting plastic. In this plastic, the molecules are combined to each other due to cross-linking in the form of cross-linkage polymer. Therefore, thermoplastic cannot be changed into various shapes after giving specific shapes. Examples: Bakelite, melamine, urea, formaldehyde, etc. Handle of pressure cooker Melamine 13.7 Bakelite 248 GREEN Science (Chemistry) Book-10

Bakelite is a thermosetting Fig. plastic. It is made by polymerization of carbolic 13.8 acid (C6H5OH) and formaldelyde (HCHO). It is very hard. It is used for making switches, plugs, sockets, handle of pressure cooker, lid of bottles, astrays, etc. Different types of plastics and their uses Plastics Uses 1. Polythene 2. PVC To make polybags, seat, polythene, etc. 3. Bakelite To make raincoat, pipe, hand bag, bottles, sole of shoe, etc. 4. Polyster To make switch, plug, socket, lid of bottle, handle of pressure 5. Polysterene cooker, astray, etc. To make thermocol, materials for packaging, and insulating materials To make container, toys and cases of refrigerator and television Characteristics of plastics 1. Plastics are bad conductors of heat and electricity. 2. They do not react with chemical substances. 3. Plastics can be recycled. 4. They are light. So, they can be transported easily. 5. They can be coloured easily. 6. They are transparent and unbreakable. 7. They do not rot. 8. They are cheap and durable. 9. They do not corrode. 10. They do not react with acids and bases. Uses of plastics 1. Plastics are used for insulating because they are bad conductor of heat and electricity. 2. They are used for making bags, pipes, bottles, etc. 3. They are used for making furniture, tunnels and parts of vehicles and aeroplanes. 4. They are used for storing various chemicals. 5. They are used for making toys, statue, windows, etc. 6. They are used for making clothes. 7. They are used for making shoes, socks, nets, etc. GREEN Science (Chemistry) Book-10 249

8. They are used for making water-proof materials. 9. They are used for making packing materials. 10. They are used for making kitchenwares. Soap Soap is a very important cleansing material. A Do You Know soap is a sodium or potassium salt of higher fatty acid. Sodium palmitate, sodium stearate and When soap is used for cleaning in hard sodium oleate are the common examples of soap. water, it reacts with salts of calcium and magnesium present in hard water and Soap was discovered before 5000 years by the forms a brown layer on the clothes called people of Babylone. They discovered the fact that scum, So soap is not suitable for cleaning when animal fat is mixed with ash and water, the purpose in hard water. mixture can be used as a cleansing agent. The first soap was used in textile factory and to treat skin diseases. The raw materials required for preparation of soap are given below: i. Animal fat or vegetable oil ii. Sodium hydroxide Simple soap is prepared by heating animal fat or vegetable oil (olive oil, coconut oil, cotton oil, etc.) with sodium hydroxide and sodium chloride. The process of making soap by heating animal fat or vegetable oil with sodium hydroxide and sodium chloride is called saponification. The chemical reaction involved in saponification is given below: Fat/Oil + Sodium hydroxide Soap + Glycerol C3H5 (OOCR)3 + 3NaOH 3NaOOCR + C5H5 (OH)3 Where, R represents hydrocarbon series i. R = C17 H35 (Stearate) ii. R = C16H33 (Oleate) iii. C15H31 (Palmitate) Soap is not suitable to wash clothes with hard water as it forms a curdy precipitate (scum) which is insoluble in water. Soap is biodegradable. So, it does not cause environmental pollution. Activity 1 Take a beaker and add 40 ml of vegetable oil into it. Take another beaker and make a solution of 15 gram sodium hydroxide in 50ml water. Mix both solutions and heat the mixture by stirring it. Add some salt and soda. Pour the mixture in a container of desired shape to make soap. This process is called saponification. 250 GREEN Science (Chemistry) Book-10