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Contents (Term II) Preface .............. ........................................................................................................................................... (v) Latest Syllabus ............................................................................................................................................ (vii) QUESTIONS 4. Carbon and its Compounds ............................................................................................................................. 2 5. Periodic Classification of Elements .............................................................................................................. 21 8. How do Organisms Reproduce ...................................................................................................................... 40 9. Heredity and Evolution ................................................................................................................................. 59 10. LightReflection and Refraction ................................................................................................................. 76 11. The Human Eye and the Colourful World ................................................................................................. 118 15. Our Environment ........................................................................................................................................ 145 16. Management of Natural Resources ............................................................................................................ 162 MCQs BASED ON PRACTICAL EXPERIMENTS Experiment 1.....................................................................................................................................................180 Experiment 2.....................................................................................................................................................183 Experiment 3 (i).................................................................................................................................................186 Experiment 3 (ii)...............................................................................................................................................189 Experiment 4.....................................................................................................................................................193 Experiment 5.....................................................................................................................................................199 Experiment 6.....................................................................................................................................................202 Value Based Questions.........................................................................................................................................205 Practice Papers (I-III).........................................................................................................................................213 xv Each chapter contains: ★ TIPS AND TRICKS ★ FORMATIVE ASSESSMENT ★ SUMMATIVE ASSESSMENT ● CBSE and Other Important Questions ● Objective Type Questions ● Higher Order Thinking Skills (HOTS) Questions ● NCERT Textbook Questions 4 Carbon and its Compounds CHAPTER Tips and Tricks l l Carbon is tetravalent and easily forms a large variety of compounds on combination with carbon and other atoms by sharing of electrons. It exhibits phenomenon of allotropy, i.e., exists in two or more forms in the same state, e.g., graphite and diamond. Covalent compounds: Some atoms share electrons among themselves or with other atoms to attain stable octet configuration. Bonds formed are covalent bonds and the compounds so formed are covalent compounds. Depending on the number of shared pair of electrons, there is single covalent bond, double covalent bond or triple covalent bond. H × × H HH Single covalent bond l l l ×× ×× × × × × × O × × O× O O Double covalent bond ethene (C2H 4), propene (C3H6), butene (C4H 8). Alkynes (CnH2n 2): ethyne (C2H2), propyne (C3H4) and butyne (C4H6). l Functional groups: Groups which determine the chemical nature of organic compounds. In a hydrocarbon, one or more hydrogen atoms are replaced by another element or group. These confer specific properties to the compound regardless of the length and nature of chain and hence are called functional groups. Name of functional group × × × × × N ×N × × × × N≡N Triple covalent bond These compounds have low m.pts. and b.pts., do not dissolve in water, do not conduct electricity and are directional in nature. Catenation is the property of carbon to get attached to other carbon atoms. Up to 60 carbon atoms are found to get attached in the shape of a ball (Fullerenes). Saturated hydrocarbons: Compounds of carbon and hydrogen attached in chains, branches or rings, by single covalent bonds, i.e., Alkanes (CnH2n + 2): methane (CH4), ethane (C2H6), propane (C3H8) and butane (C4H10). Unsaturated hydrocarbons are compounds of carbon and hydrogen with either carbon-carbon double bond (C = C) or carbon-carbon triple bond (C ≡ C) in their molecules, e.g., Alkenes (CnH2n): Formula of functional group Halo Cl, Br, I Alcohol OH Aldehyde C Ketone | C = O Carboxylic acid C H O O OH l l 2 Homologous series is a group or family of compounds which contain the same functional group but have different chain lengths. Two successive homologous differ by one carbon and two hydrogen atoms in their molecular formulae. (Note that alkanes, alkenes and alkynes are also different homologous series). Isomerism: In carbon compounds, different compounds are formed with different structures with the same molecular formula. These compounds are called isomers and the phenomenon is called isomerism. For example, butane (C4H10) can be written as CARBON AND ITS COMPOUNDS l 3 H3CCH2CH2CH3 (n-butane) and H3CCHCH3 (iso-butane) CH3 Nomenclature of carbon compounds (i) Identify the number of carbon atoms in the main chain, e.g., methane, ethane, propane, butane for one, two, three, four carbon atoms etc. (ii) The name of functional group can be given either a prefix or suffix (see table below). If the functional group is used as suffix, e of hydrocarbon is substituted by suffix. H 2 1 H3C CBr Br 1, 1-dibromoethane l Chemical properties of carbon compounds: Carbon and its compounds burn in oxygen with liberation of heat and light. Saturated hydrocarbons burn with a blue flame and unsaturated hydrocarbons with a yellow flame. l Addition reactions: Unsaturated hydrocarbons add up hydrogen or halogens. (iii) The carbon atoms are numbered from the side of functional group. Functional group Halogen Prefix/Suffix Example prefixchloro H3CCH2CH2Cl CH2 = CH2 + H2 → CH3 CH3 CH2 = CH2 + Br2 → CH2Br CH2Br. l Chloropropane Alcohol suffixol H3CCH2CH2OH Propanol Aldehyde suffixal CH4 + Cl2 → CH3Cl + HCl. l H3CCH2 C H || O (ii) It can be dehydrated (C2H5OH → CH2 = CH2 + H2O) at 443 K with excess concentrated sulphuric acid. H3C C = O | CH 3 suffixone (iii) Esterification: Reaction in which alcohol combines with carboxylic acid in the presence of conc. sulphuric acid. Propanone Carboxylic suffixoic acid acid H3CCH2 C = O | OH conc. → C2H5OH + CH3COOH H SO Propanoic acid Double bond Ethanol or Ethyl alcohol H | H3C C = CH2 suffixene suffixyne H3CC ≡ CH Propyne l 2, 2-dimethyl propane 4 3 2 1 H3C C ≡ C CH3 2-butyne 2 4 CH3COOC2H5 + H2O (iv) It gives ethanal (acetaldehyde) in the presence of mild oxidising agent like cupric oxide (Cu2O), and acetic acid in the presence of acidified potassium dichromate. Other examples CH3 3 2 1 CH3 CCH3 CH3 Acetic acid Ethyl ethanoate or Ethyl acetate Propene Triple bond Ethanol is produced on a large-scale by the fermentation of sugar or starch with enzymes (invertase and zymase) present in the yeast. (i) It reacts vigorously with sodium with evolution of H2. Propanol Ketone Substitution reactions: In the presence of light, halogens are substituted with hydrogen in saturated hydrocarbons l Denatured alcohol: To make alcohol unfit for drinking it is mixed with poisonous substances like methanol, pyridine and blue dyes. 4 CCE SCIENCE—X l Ethanoic acid gets neutralized by bases like sodium hydroxide, sodium carbonate or sodium bicarbonate to give sodium acetate salt. l Soaps are sodium or potassium salts of long chain carboxylic acid molecules in which two ends have different properties, one is hydrophilic which dissolves in water), while the other end is hydrophobic (dissolves in hydrocarbons). When cleansing clothes, hydrophobic part attaches to dirt (oily in nature) and hydrophilic part attaches to water which on washing pulls away the hydrophobic part along with dirt. l Detergents are similar to soaps but hydrocarbon part here is obtained from petroleum. Formative Assessment ORAL QUESTIONS (Conversation Type) 1. (a) What is peculiar about carbon? (b) What is catenation? (c) What is the cause of this property? (d) Si is also tetravalent but it does not show this peculiar property. 2. (a) What name is given to compounds of carbon with hydrogen? (b) Are all hydrocarbon similar? (c) How are saturated hydrocarbons different from unsaturated hydrocarbons? (d) What other name is given to saturated hydrocarbons? (e) What other name is given to unsaturated hydrocarbons? 3. (a) What is a homologous series? (b) In what way two consecutive members of a homologous series differ? (c) Do they have any effect on their physical properties? (d) What about chemical properties? 5. Why covalent compounds are generally low melting? 6. What is allotropy? 7. Name the allotropes of carbon. 8. How does carbon occur in free state in nature? 9. What is catenation? 10. What is the name of a hydrocarbon having 3 carbon atoms? 11. Give the name of an unsaturated hydrocarbon with 2 carbon atoms. 12. Give an account of nature of bonds in ethyne. 13. Which part of carbon compounds determine their chemical properties? 14. What are isomers? 15. Name a functional group which gives acidic character to carbon compounds. 16. What are fatty acids? 17. Which type of hydrocarbons give addition products? 18. What is the name given to generally sweet smelling organic compounds? (e) Why similar chemical properties? (f) What are functional groups? ORAL QUESTIONS 1. What is a covalent bond? 2. How are methane bond formed? 3. What is a double covalent bond? 4. How are ethene bond formed? TRUE OR FALSE 1. Carbon like other tetravalent atoms exhibit phenomenon of allotropy. 2. Carbon atoms combine with other atoms to form both ionic as well as covalent bonds. 3. Compounds containing only carbon and hydrogen are called hydrocarbons. CARBON AND ITS COMPOUNDS 5 4. The functional group is attached to the carbon chain by replacing hydrogen atom. formula may exist with different structural formulae. 5. Compounds with formula CnH2n are called unsaturated hydrocarbons. 8. I am a saturated hydrocarbon which can be present as three isomers. 6. Synthetic detergents are sodium or potassium salts of long chain carboxylic acids. 9. I am composed of long chain carbon atoms with carboxylic acid attached at the end. 7. Chlorine and oxygen are most likely to form either ionic bonds or covalent bonds. 8. Graphite unlike diamond is a conductor of electricity. 10. I am a brown coloured non-metal and, if present as dilute solution, get decolourised by unsaturated hydrocarbons. 9. All hydrocarbons show phenomena of isomerism. 10. The members of a homologous series have similar chemical and physical properties. PUZZLES A. ⇒ Across 1. A phenomenon in which two or more compounds with same molecular formulae give different structures. (9) 11. Cyclic hydrocarbons are saturated or unsaturated organic compounds that contain ring of carbon atoms. 3. Sweet smelling compounds. (6) 12. Structural formula of 2-butyne contains one triple bond and 4 single bonds. ⇓ Down 13. Both alcohol and carboxylic acids react with sodium metal and give H2 with effervescence. 2. Element possessing two or more forms in the same state. (9) 14. Esters are used in making perfumes and flavouring agents. 4. Breaking down of organic compounds by microorganisms. (12) 15. Ethyl alcohol is obtained by the fermentation of molasses with enzymes in the absence of air. 2 QUIZ 1. I am a process to produce alcohol on a large scale. 2. Though small in size, branch of organic chemistry has no existence without me. 4 1 3 O E T R 3. We are a large group of compounds but constituted of only two elements. 4. I am a type of bond which is characteristic of all types of organic compounds. 5. I give a relation between graphite and diamond. 6. I am a series that separates one type of chemical active compound from the other similarly active compound. 7. I represent the phenomenon in which two or more compounds having the same molecular O 6 CCE SCIENCE—X 2 1 3 H L O C A 4 G R S B. ⇒ Across 1. A series of compounds which contain same functional group. (10) 3. Compounds of carbon and hydrogen. (12) ⇓ Down 2. Sodium salts of fatty acids. (5) 4. A form of carbon which conducts electricity. (8) SUGGESTED PROJECTS/ACTIVITIES 1. Students can prepare soap either at home or in the laboratory and whether it forms lather with tap water and underground water. 2. Students can prepare esters in the laboratory and compare its smell with perfumes available. E NOTES CARBON AND ITS COMPOUNDS 7 Assignments Name: ........................ Class: ...... Section: ...... Roll No.: ...... Grade: ...... Teachers sign.: .............. CLASS ASSIGNMENT 1. Name the form of carbon which is used as a lubricant at high temperature. .............................................................................. 2. What is saponification? 5. An organic compound with molecular formula as C2H4O2 is widely used as a preservative in pickles. Identify the compound. Explain its reaction with ethanol and sodium metal. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. 3. How are synthetic detergents structurally different from soaps? Write their advantages over soaps. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. 6. Give two examples of fermentation that you come across in your daily life. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. 4. Explain the following: (a) Carbon forms compounds mainly by covalent bonding. (b) Carbon forms a large no. of compounds as compared to other members of its group. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. 7. Giving examples, explain the difference between combustion and oxidation. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. 8 CCE SCIENCE—X 8. What are isomers? State four characteristics of isomers. .............................................................................. 10. A hydrocarbon has 3 carbon atoms. Write all the possible structures of the hydrocarbons formed. Give their name and suggest how will you distinguish between them. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. 9. Classify the following compounds as alkane, alkyne or alkene. C3H4, C2H6, C2H4, C6H14, C2H2, C4H6, C5H12, C5H8, C3H8 Which of these can be called as members of a homologous series? .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. .............................................................................. NOTES CARBON AND ITS COMPOUNDS 9 Name: ........................ Class: ...... Section: ...... Roll No.: ...... Grade: ...... Teachers sign.: .............. HOME ASSIGNMENT 1. What is the name given to allotropes of carbon? (a) In which compound carbon atoms are arranged in the shape of a football. (b) In which compound carbon atom is attached tetrahedrally to four other carbon atoms forming a network of carbon chains. (c) In which compound carbon atom is attached to only three carbon atoms forming uniplanar layers which in turn are attached to similar layers by van der Waals forces? ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... 4. What is a homologous series of compounds? List any two characteristics of a homologous series. ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... 2. Give a brief account of the nature of bonds in propyne (propylene). ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... 3. What is the difference between functional group and alkyl radical? Give the name and formula of some common functional groups. ............................................................................... ............................................................................... ............................................................................... ............................................................................... 5. Identify the functional group in the following compound: CH2Br2. Give its common name and IUPAC names. ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... 10 CCE SCIENCE—X 6. How are carboxylic acids named? How will you distinguish these from alcohols? ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... 9. Write notes on (a) Molasses (b) Denatured alcohol (c) Yeast ............................................................................... ............................................................................... ............................................................................... 7. Describe how petroleum was formed under the earth. Give the separation technique to separate components of petroleum. ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... 10. What are micelles? How does the formation of a micelle help to clean the clothes? ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... 8. Distinguish between addition and substitution reactions. Give one example of each. ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ............................................................................... ...............................................................................
