{"id":24060,"date":"2024-10-15T10:30:54","date_gmt":"2024-10-15T05:00:54","guid":{"rendered":"https:\/\/samacheerkalvi.guide\/?p=24060"},"modified":"2024-10-16T09:55:28","modified_gmt":"2024-10-16T04:25:28","slug":"samacheer-kalvi-9th-science-guide-chapter-15","status":"publish","type":"post","link":"https:\/\/samacheerkalvi.guide\/samacheer-kalvi-9th-science-guide-chapter-15\/","title":{"rendered":"Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds"},"content":{"rendered":"

Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide<\/a> Pdf Chapter 15 Carbon and its Compounds Text Book Back Questions and Answers, Notes.<\/p>\n

Samacheer Kalvi 9th Science Solutions Chapter 15 Carbon and its Compounds<\/h2>\n

9th Science Guide Carbon and its Compounds Text Book Back Questions and Answers<\/h3>\n

\"<\/p>\n

I. Choose the correct answer :<\/span><\/p>\n

Question 1.
\nA phenomenon in which an element exists in different modification in same physical state is called
\n(a) isomerism
\n(b) allotropy
\n(c) catenation
\n(d) crystallinity
\nAnswer:
\n(b) allotropy<\/p>\n

Question 2
\nCarbon forms large number of organic compounds due to
\n(a) Allotropy
\n(b) Isomerism
\n(c) Tetravalency
\n(d) Catenation
\nAnswer:
\n(d) Catenation<\/p>\n

\"<\/p>\n

Question 3.
\nNandhini brings her lunch every day to school in a plastic container which has resin code number 5. The container is made of
\n(a) Polystyrene
\n(b) PVC
\n(c) Polypropylene
\n(d) LDPE
\nAnswer:
\n(c) Polypropylene<\/p>\n

Question 4.
\nPlastics made of Polycarbonate (PC) and Acrylonitrile Butadiene Styrene (ABS) . are made of resin code …………………
\n(a) 2
\n(b) 5
\n(c) 6
\n(d) 7
\nAnswer:
\n(a) 7<\/p>\n

\"<\/p>\n

Question 5.
\nGraphene is one atom thick layer of carbon obtained from
\n(a) diamond
\n(b) fiillerene
\n(c) graphite
\n(d) gas carbon
\nAnswer:
\n(c) graphite<\/p>\n

\"<\/p>\n

Question 6.
\nThe legal measures to prevent plastic pollution come under the Protection …………….. Act 1988.
\n(a) Forest
\n(b) Wildlife
\n(c) Environment
\n(d) Human rights
\nAnswer:
\n(c) Environment<\/p>\n

II. Fill in the blanks :<\/span><\/p>\n

1. ………………. named carbon.
\nAnswer:
\nAntoine Lavoisier<\/p>\n

2. Buckminster Fullerene contains ………………… carbon atoms.
\nAnswer:
\n60<\/p>\n

3. Compounds with same molecular formula and different structural formula are known as ………………….. .
\nAnswer:
\nIsomers<\/p>\n

\"<\/p>\n

4. …………….. is a suitable solven for Sulphur.
\nAnswer:
\nAllotropy<\/p>\n

5. There are ……………. plastic resin codes.
\nAnswer:
\nseven<\/p>\n

III. Match the following :<\/span><\/p>\n\n\n\n\n\n\n\n
Alkyne<\/td>\nBucky Ball<\/td>\n<\/tr>\n
Andre Geim<\/td>\nOxidation<\/td>\n<\/tr>\n
C60<\/sub><\/td>\nGraphene<\/td>\n<\/tr>\n
Thermocol<\/td>\nTriple bond<\/td>\n<\/tr>\n
Combution<\/td>\nPolystyrene<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Answer:<\/p>\n\n\n\n\n\n\n\n
Alkyne<\/td>\nTriple bond<\/td>\n<\/tr>\n
Andre Geim<\/td>\nGraphene<\/td>\n<\/tr>\n
C60<\/sub><\/td>\nBucky Ball<\/td>\n<\/tr>\n
Thermocol<\/td>\nPolystyrene<\/td>\n<\/tr>\n
Combution<\/td>\nOxidation<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\"<\/p>\n

IV. Answer in briefly :<\/span><\/p>\n

Question 1.
\nDifferentiate graphite and diamond.
\nAnswer:<\/p>\n\n\n\n\n\n\n\n
Graphite<\/td>\nDiamond<\/td>\n<\/tr>\n
Each carbon atom has three covalent bonds.<\/td>\nEach carbon atom has four covalent bonds.<\/td>\n<\/tr>\n
Soft, slippery to touch and opaque<\/td>\nHard, heavy and transparent<\/td>\n<\/tr>\n
It has planar layers of hexagon units.<\/td>\nIt has tetrahedral units linked in three dimension<\/td>\n<\/tr>\n
It is conductor of heat and electricity.<\/td>\nIt is non-conductor of heat and electricity<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Question 2.
\nWrite all possible isomers of C4<\/sub>H10<\/sub>
\nAnswer:
\n\"Samacheer<\/p>\n

Question 3.
\nCarbon forms only covalent compounds. Why?
\nAnswer:
\nCarbon forms only covalent compounds because it has 4 electrons, in its.<\/p>\n

\"<\/p>\n

Question 4.
\nDefine Allotrophy.
\nAnswer:
\nAllotrophy is a property by which are element can exist in more than one form that are physically different and chemically similar.<\/p>\n

Samacheer Kalvi 9th Science Guide Chapter 15 Carbon and its Compounds 1<\/p>\n

Question 5.
\nWhy are one-time use and throwaway plastics harmful?
\nAnswer:<\/p>\n

    \n
  1. Use and throwaway plastics cause short and long-term environmental damage.<\/li>\n
  2. Half of all the plastic made today is used for throwaway plastic items. These block drains and pollute water bodies.<\/li>\n
  3. One-time use plastic causes health problems for humans, plants and animals.<\/li>\n
  4. Some examples are plastic carry bags, cups, plates, straws, water pouches, cutlery and plastic sheets used for food wrapping.<\/li>\n<\/ol>\n

    \"<\/p>\n

    V. Answer in detail :<\/span><\/p>\n

    Question 1.
    \nWhat is catenation? How does carbon form catenated compounds?
    \nAnswer:
    \nCatenation is binding of an element to itself or with other elements through covalent bonds to form open chain or closed chain compounds.<\/p>\n

      \n
    • Carbon is the most common element which undergoes catenation and long chain compounds.<\/li>\n
    • Carbon atom links repeatedly to itself through covalent bond to form linear branched chain (or) ring structure<\/li>\n<\/ul>\n

      \"Samacheer<\/p>\n

        \n
      • This property of carbon itself is the reason for the presence of large number of organic carbon compounds.<\/li>\n
      • So organic chemistry essentially deals with catenated carbon compounds.<\/li>\n
      • Example: Starch and cellulose contain chains of hundreds of carbon atoms.<\/li>\n<\/ul>\n

        Question 2.
        \nWhat are the chemical reactions of carbon?
        \nAnswer:
        \nElemental carbon undergoes no reaction at room temperature.
        \nOxidation : Carbon combines with oxygen to form its oxides such as carbon monoxide (CO) and carbon dioxide (CO2<\/sub>), with evolution of heat. Organic carbon compounds like hydrocarbon also undergo oxidation to form oxides and steam with evolution of heat and flame.<\/p>\n

        This reaction is also called \u2018Combustion\u2019.
        \n\"Samacheer<\/p>\n

        Reaction with Steam : Carbon reacts with steam to form carbon monoxide hydrogen. This mixture is called water gas.
        \nC(S)<\/sub> + H2<\/sub>O(g)<\/sub> \u2192 CO(g)<\/sub> + H2(g)<\/sub><\/p>\n

        Reaction with Sulphur: With sulphur, carbon forms its disuiphide at high temperature.
        \nC(S)<\/sub> + S(g)<\/sub> \u2192 CS2(g)<\/sub><\/p>\n

        Reaction with Metals : At elevated temperatures, carbon reacts with some metals like iron, tungsten, titanium, etc., to form their carbides
        \nW(S)<\/sub>+C(g)<\/sub> \u2192 WC(S)<\/sub><\/p>\n

        \"
        \nQuestion 3.
        \nName the three safer resin codes of plastics and describe their features.
        \nAnswer:
        \n\"Samacheer<\/p>\n

        VI. Higher Order Thinking Skills:<\/span><\/p>\n

        Question 1.
        \nWhy do carbon exist mostly in combined state?
        \nAnswer:
        \nCarbon is an element that can form many different compounds, as each carbon atom can form 4 chemical bonds with other atoms and because the carbon atom is just the right size to fit in comfortably as parts of very large molecules.<\/p>\n

        \"<\/p>\n

        Question 2.
        \nWhen a carbon fuel burns in less aerated room, it is dangerous to stay there. Why?
        \nAnswer:<\/p>\n

          \n
        • When a carbon fuel bums in less aerated room, the fuel may undergo incomplete combustion.<\/li>\n
        • It results in the formation of carbon monoxide.<\/li>\n
        • When exposed to carbon monoxide (CO) it enters human body, through breathing, affects the function of haemoglobin.<\/li>\n
        • Sometimes, it will lead to death.<\/li>\n<\/ul>\n

          Question 3.
          \nExplain how dioxins are formed? Which plastic-type they are linked to and why they are harmful to humans?
          \nAnswer:
          \nDioxin formation:<\/p>\n

            \n
          • Dioxin compounds are not created intentionally but are formed inadvertently by a number of human and natural activities.<\/li>\n
          • These activities include combustion and incineration, forest fires, chlorine bleaching of pulp and paper, certain types of chemical manufacturing and processing, and other industrial processes.<\/li>\n
          • Cigarette smoke, some home-heating systems, and exhaust from vehicles using leaded and unleaded petrol as well as diesel fuels also produce small amounts of dioxins.<\/li>\n
          • Burning materials that may contain chlorine such as plastics, wood treated with pentachlorophenol (PCP), pesticide-treated wastes, other chemicals such as polychlorinated biphenols (PCBs<\/sub>), and even bleached paper can produce dioxins.<\/li>\n<\/ul>\n

            Their link with plastic :<\/p>\n

              \n
            • Dioxins are linked with PVC (Polyvinyl Chloride plastics).<\/li>\n
            • The most dangerous emissions can be caused by burning PVC, as it releases dioxins.<\/li>\n<\/ul>\n

              Harmful effects of Dioxins to humans :<\/p>\n

                \n
              • Dioxins are the most toxic to human organisms.<\/li>\n
              • Dioxins can cause cancer, disrupt the endocrine system, alteration in pituitary and thyroid gland functions, immune suppression, neurobehavioral effects and cause reproductive and developmental effects.<\/li>\n
              • They are carcinogenic and a hormone disruptor and persistent, and they accumulate in our body-fat and thus mothers give it directly to their babies via the placenta.<\/li>\n<\/ul>\n

                \"<\/p>\n

                Question 4.
                \nYugaa wants to buy a plastic water bottle. She goes to the shop and sees four different kinds of plastic bottles with resin codes 1, 3, 5, and 7. Which one should she buy? Why?
                \nAnswer:<\/p>\n

                  \n
                • Yugaa should buy a plastic water bottle with Resin Code No.5, which is considered as one of the safer plastics. It is light and hard.<\/li>\n<\/ul>\n

                  Reasons to avoid resin codes 1,3,7<\/p>\n

                    \n
                  • Bottle with Resin Code 1 is to be used only once. This plastic can release a chemical additive called antimony, which is not good for health.<\/li>\n
                  • Bottle with Resin Code 3 is the most toxic plastic. It will have a smell of a new shoe. It should be avoided.<\/li>\n
                  • Bottle with Resin Code 7 has the plastic types PC and ABS which are unsafe and toxic.<\/li>\n<\/ul>\n

                    Intext Activities<\/strong><\/p>\n

                    ACTIVITY -1<\/span>
                    \nWith the help of your teacher, try to classify the following as organic and inorganic compounds.
                    \nHCN, CO2<\/sub>, Propane, PVC, CO Kerosene, LPG, Coconut oil, Wood, Perfume, Alcohol, Na2<\/sub>CO3<\/sub>, CaCO3<\/sub>. MgO, Cotton, Petrol.
                    \nSolution:<\/p>\n\n\n\n\n\n\n\n\n\n\n
                    Inorganic<\/td>\nOrganic<\/td>\n<\/tr>\n
                    CO2<\/sub><\/td>\nPropane<\/td>\n<\/tr>\n
                    CO<\/td>\nWood, kerosene, coconut oil<\/td>\n<\/tr>\n
                    MgO<\/td>\nParfume<\/td>\n<\/tr>\n
                    HCN<\/td>\nAlcohol<\/td>\n<\/tr>\n
                    Na2<\/sub>CO3<\/sub><\/td>\nCotton<\/td>\n<\/tr>\n
                    PVC<\/td>\nPetrol<\/td>\n<\/tr>\n
                    <\/td>\nLPG<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                    [End of the activity]<\/p>\n

                    \"<\/p>\n

                    ACTIVITY – 2<\/span><\/p>\n

                    Take a football since it resembles Buckminsterfullerene. Count how many hexagonal and pentagonal panels are in it very comer is considered as one carbon. Compare your observation with fullerene and discuss with your friends.
                    \nAim:
                    \nTo compare the structure of fullerene with football.
                    \nMaterials required:
                    \nFootball<\/p>\n

                    Procedure:<\/p>\n

                      \n
                    1. Take football.<\/li>\n
                    2. Count the hexagonal and pentagonal rings shapes in football.<\/li>\n<\/ol>\n

                      Observation:<\/p>\n\n\n\n\n\n\n
                      Shapes<\/td>\nFullerene (C60<\/sub>)<\/td>\nFootball<\/td>\n<\/tr>\n
                      Pentagon<\/td>\n12 Pentagonal rings<\/td>\n12 Black pentagons<\/td>\n<\/tr>\n
                      Hexagon<\/td>\n20 Hexagonal rings<\/td>\n20 White hexagons<\/td>\n<\/tr>\n
                      Structure<\/td>\nClosed cage-like structure<\/td>\nPolyhedron Structure<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                      Conclusion :
                      \nThe structure of football is compared with fullerene.<\/p>\n

                      9th Science Guide Carbon and its Compounds Additional Important Questions and Answers<\/h3>\n

                      I. Choose the correct answer :<\/span><\/p>\n

                      Question 1.
                      \nCarbon is one of the most important ………………….element.
                      \n(a) Metallic
                      \n(b) Non-metallic
                      \n(c) Metalloid _
                      \n(d) None of these
                      \nAnswer:
                      \n(b) Non-metallic<\/p>\n

                      Question 2.
                      \nThe most recently discovered allotrope of carbon is ……………….
                      \n(a) Graphite
                      \n(b) Fullerene
                      \n(c) Graphene ‘
                      \n(d) Gas carbon
                      \nAnswer:
                      \n(c) Graphene<\/p>\n

                      \"<\/p>\n

                      Question 3.
                      \n……………. is the first organic compound synthesized in the laboratory.
                      \n(a) Urea
                      \n(b) Acetic acid
                      \n(c) Methane
                      \n(d) Ethanol
                      \nAnswer:
                      \n(a) Urea<\/p>\n

                      Question 4.
                      \nThe main component of water gas is …………….
                      \n(a) Carbon dioxide
                      \n(b) Carbon monoxide
                      \n(c) Calcium carbide
                      \n(d) Methane
                      \nAnswer:
                      \n(b) Carbon monoxide<\/p>\n

                      \"<\/p>\n

                      Question 5.
                      \nThe ability of carbon to form …………… is the main reason for the formation of various classes of carbon compounds.
                      \n(a) Tetravalency
                      \n(b) Catenation
                      \n(c) Isomerism
                      \n(d) Multiple bonds
                      \nAnswer:
                      \n(d) Multiple bonds<\/p>\n

                      Question 6.
                      \nArrangement of atoms in diamond is …………………
                      \n(a) Hexagonal
                      \n(b) Trigonal
                      \n(c) Tetrahedral
                      \n(d) Pentagonal
                      \nAnswer:
                      \n(c) Tetrahedral<\/p>\n

                      \"<\/p>\n

                      Question 7.
                      \nThe amorphous allotropic carbon used for making electrodes in dry cell
                      \n(a) Coke
                      \n(b) Charcoal
                      \n(c) Lampblack
                      \n(d) Gas carbon
                      \nAnswer:
                      \n(d) Gas carbon<\/p>\n

                      Question 8.
                      \nElemental carbon undergoes …………. reaction at room temperature.
                      \n(a) Oxidation
                      \n(b) Reduction
                      \n(c) Free radical
                      \n(d) no.
                      \nAnswer:
                      \n(d) no<\/p>\n

                      \"<\/p>\n

                      Question 9.
                      \nAmorphous forms of carbon and graphite are almost …………… in colour.
                      \n(a) Grey
                      \n(b) brownish
                      \n(c) black
                      \n(d) dirty white
                      \nAnswer:
                      \n(c) black<\/p>\n

                      Question 10.
                      \nCarbon monoxide displaces ………………. from hemoglobin.
                      \n(a) nitrogen
                      \n(b) oxygen
                      \n(c) hydrogen
                      \n(d) carbon dioxide
                      \nAnswer:
                      \n(b) oxygen<\/p>\n

                      \"<\/p>\n

                      Question 11.
                      \nBurning of PVC releases
                      \n(a) Dioxins
                      \n(b) Carbon monoxide
                      \n(c) Sulphur dioxide
                      \n(d) Chlorine
                      \nAnswer:
                      \n(a) Dioxins<\/p>\n

                      Question 12.
                      \nWhich among the following plastics release antimony when we reuse.
                      \n(a) PVC
                      \n(b) HDPE
                      \n(c) PP
                      \n(d) PET
                      \nAnswer:
                      \n(d) PET<\/p>\n

                      Question 13.
                      \nAccording to the Octet rule, carbon requires ……………. electrons to attain the nearest noble gas.
                      \n(a) One
                      \n(b) two
                      \n(c) Three
                      \n(d) Four
                      \nAnswer:
                      \n(d) Four<\/p>\n

                      \"<\/p>\n

                      Question 14.
                      \nMost one-time use plates are made from ……………
                      \n(a) Polypropylene
                      \n(b) Polystyrene
                      \n(c) Polyethylene
                      \n(d) Polyvinylchloride
                      \nAnswer:
                      \n(b) Polystyrene<\/p>\n

                      Question 15.
                      \nWhich among the following compound is soluble in water?
                      \n(a) Methane
                      \n(b) Ethylene
                      \n(c) Ethanol
                      \n(d) Phenol
                      \nAnswer:
                      \n(c) Ethanol<\/p>\n

                      \"<\/p>\n

                      Question 16.
                      \nThe number of free electrons in each carbon of diamond is
                      \n(a) Zero
                      \n(b) One
                      \n(c) Two
                      \n(d) None of these
                      \nAnswer:
                      \n(a) zero<\/p>\n

                      Question 17.
                      \nThe carbon atoms in Graphene are arranged in
                      \n(a) Hexagon
                      \n(b) Pentagon
                      \n(c) octagon
                      \n(d) Tetragon
                      \nAnswer:
                      \n(a) Hexagon<\/p>\n

                      \"<\/p>\n

                      Question 18.
                      \nResin Code\u201d represents the type of …………….. used to make the plastic.
                      \n(a) Polymer
                      \n(b) Rubber
                      \n(c) monomer
                      \n(d) Polymerisation
                      \nAnswer:
                      \na) Polymer<\/p>\n

                      Question 19.
                      \nDiamond is not a good conductor of electricity because
                      \n(a) it is very hard
                      \n(b) it has no free electron
                      \n(c) its structure is uniform
                      \n(d) it is insoluble in water
                      \nAnswer:
                      \n(b) it has no free electron
                      \nHint: Diamond contains no free electron and it behaves as an insulator<\/p>\n

                      \"<\/p>\n

                      Question 20.
                      \nWhich of the following is highly toxic?
                      \n(a) Carbon dioxide
                      \n(b) Carbon monoxide
                      \n(c) Calcium carbonate
                      \n(d) Sodium bicarbonate
                      \nAnswer:
                      \n(b) Carbon monoxide
                      \nHint: CO easily binds with Haemoglobin and then causes death<\/p>\n

                      Question 21.
                      \nWhich of the following plastic items are banned by the Government of Tamil Nadu as of 1st January 2019?
                      \n(a) Plastic sheets
                      \n(b) Plastic teacups
                      \n(c) Plastic water packet
                      \n(d) All the above
                      \nAnswer:
                      \n(d) All the above<\/p>\n

                      \"<\/p>\n

                      Question 22.
                      \nGraphite is used as a lubricant in machines because
                      \n(a) it is a good conductor of electricity
                      \n(b) it is made of slippery layers and\u00a0 has a high melting point
                      \n(c) it has a high density
                      \n(d) it is strong and soft
                      \nAnswer:
                      \n(b) it is made of slippery layers and has a high melting point<\/p>\n

                      Question 23.
                      \nPlastic resin codes are shown as three chasing arrows in a ………………. with a number in the middle or letters (an acronym of that plastic type).
                      \n(a) Logo
                      \n(b) Recycling Symbol
                      \n(c) Square
                      \n(d) Triangle
                      \nAnswer:
                      \n(d) Triangle<\/p>\n

                      \"<\/p>\n

                      II. Fill in the blanks :<\/span><\/p>\n

                      1. …………… is the main constituent of coal.
                      \nAnswer:
                      \nCarbon<\/p>\n

                      2. Carbon chemistry is also called as ……………..
                      \nAnswer:
                      \nLiving chemistry<\/p>\n

                      3. Graphene has a thickness of just …………… atom.
                      \nAnswer:
                      \nOne<\/p>\n

                      \"<\/p>\n

                      4. ……………. is the Father of Modem Organic Chemistry
                      \nAnswer:
                      \nFriedrich Wohler<\/p>\n

                      5. The inorganic carbon compound that takes past in photosynthesis is …………………….
                      \nAnswer:
                      \nCarbon dioxide<\/p>\n

                      6. The carbon cycle is the …………….. cycle.
                      \nAnswer:
                      \nBiogeochemical<\/p>\n

                      \"<\/p>\n

                      7. ……………….. structure accountable for hardness and rigidity of diamond.
                      \nAnswer:
                      \nThree dimensional<\/p>\n

                      8. Hexagonal layers in Graphite are held together by ……………………
                      \nAnswer:
                      \nweak VanderWaals forces<\/p>\n

                      9. Pet name for Buckminster Fullerene is ………………….
                      \nAnswer:
                      \nBucky ball<\/p>\n

                      \"<\/p>\n

                      10. A large family of fullerene exists, starting at ………………… and reaching upto .
                      \nAnswer:
                      \nC20<\/sub>, C540<\/sub><\/p>\n

                      11. Graphene is ………………. shaped hexagonal ring
                      \nAnswer:
                      \nHoneycomb<\/p>\n

                      12. Cigarette smoking is a source of ……………….
                      \nAnswer:
                      \nCarbon Monoxide<\/p>\n

                      \"<\/p>\n

                      13. Carbon monoxide enters into human body through …………………
                      \nAnswer:
                      \nbreathing<\/p>\n

                      14. Do not use _______ for school projects.
                      \nAnswer:
                      \nThermocol<\/p>\n

                      15. Polycarbonate (PC) plastic contains ……………..
                      \nAnswer:
                      \nBisphenol A<\/p>\n

                      \"<\/p>\n

                      III. Match the following :<\/span>
                      \n(I)<\/p>\n\n\n\n\n\n\n
                      1. Graphite<\/td>\na) Honeycomb<\/td>\n<\/tr>\n
                      2. Fullerene<\/td>\nb) Tetrahedral<\/td>\n<\/tr>\n
                      3. Graphene<\/td>\nc) Hexagonal<\/td>\n<\/tr>\n
                      4. Diamond<\/td>\nd) Dome-shaped<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                      Answer:
                      \n1 – c, 2 – d, 3 – a, 4 – b<\/p>\n

                      (II)
                      \n\"Samacheer
                      \nAnswer:
                      \n1-b,2-c,3-a,4-d<\/p>\n

                      (III)
                      \n\"Samacheer
                      \nAnswer:
                      \n1-c, 2 -a, 3-b, 4-c<\/p>\n

                      IV. True or False :<\/span><\/p>\n

                      1. About 18% of the weight of the human body is carbon.
                      \nAnswer:
                      \nTrue.<\/p>\n

                      2. There is more abundance of carbon in the earth
                      \nAnswer:
                      \nFalse.
                      \nCorrect statement: There is less abundance of carbon in the earth.<\/p>\n

                      \"<\/p>\n

                      3. Carbon has the tendency to lose its four electrons with that of other atoms to complete its octet.
                      \nAnswer:
                      \nFalse.
                      \nCorrect statement: Carbon has the tendency to share its four electrons with that of other atoms to complete its octet<\/p>\n

                      4. All the allotropic forms of carbon are solids.
                      \nAnswer:
                      \nTrue.<\/p>\n

                      5. Carbon\u2019s amorphous forms have high melting and boiling poult compared to crystalline forms.
                      \nAnswer:
                      \nFalse.
                      \nCorrect statement: Carbon\u2019s amorphous forms have low melting and boiling point compared to crystalline forms.<\/p>\n

                      \"<\/p>\n

                      6. Used plate is easy to recycle.
                      \nAnswer:
                      \nFalse.
                      \nCorrect statement: Used plate difficult to recycle.<\/p>\n

                      7. Do not eat hot food items in plastic containers.
                      \nAnswer:
                      \nTrue.<\/p>\n

                      V. Assertion and Reason type questions :<\/span><\/p>\n

                      Mark the correct choice as:
                      \n(a) If both Assertion and Reason are true and Reason is the correct explanation of Assertion.
                      \n(b) If both assertion and reason are true but the reason is not the correct explanation of assertion.
                      \n(c) If Assertion is true but the reason is false.
                      \n(d) Both assertion and reason are false.<\/p>\n

                      Question 1.
                      \nAssertion (A) : The number of carbon compounds alone is more than the number of compounds of all the elements taken together.
                      \nReason (R) : Carbon has some unique properties such as
                      \n1) Catenation, 2) Tetravalency, 3) Multiple bonds, 4) Allotropy, 5) Isomerism.
                      \nAnswer:
                      \n(a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion<\/p>\n

                      \"<\/p>\n

                      Question 2.
                      \nAssertion (A) : There are various classes of carbon compounds formed.
                      \nReason (R) : The property of Isomerism is the main reason.
                      \nAnswer:
                      \n(c) Assertion is true but reason is false
                      \nReason : The ability to form multiple bonds is the main reason.<\/p>\n

                      Question 3.
                      \nAssertion (A) : Carbon monoxide is a toxic gas of carbon.
                      \nReason (R): smoking is a source of carbon monoxide.
                      \nAnswer:
                      \n(b) Both assertion and reason are true but reason is not the correct explanation for assertion<\/p>\n

                      Question 4.
                      \nAssertion (A): PVC is an unsafe plastic.
                      \nReason (R)Burning PVC releases dioxins, a most toxic chemical.
                      \nAnswer:
                      \n(a) Both Assertion and Reason are true and Reason is the correct explanation for Assertion<\/p>\n

                      \"<\/p>\n

                      VI. Answer the following by rearranging the jumbled letters :<\/span><\/p>\n

                      Question 1.
                      \nIt is the hardest allotrope of carbon
                      \nmnodaid
                      \nAnswer:
                      \nDiamond<\/p>\n

                      Question 2.
                      \nOrganic compounds having a double bond between carbon atoms are
                      \nknelaes
                      \nAnswer:
                      \nAlkenes<\/p>\n

                      \"<\/p>\n

                      Question 3.
                      \nReaction of carbon with oxygen gives
                      \nosdiex
                      \nAnswer:
                      \nOxides<\/p>\n

                      Question 4.
                      \nIn this molecule, carbon is attached to four hydr\u00f5gen atoms.
                      \nemathen
                      \nAnswer:
                      \nMethane<\/p>\n

                      \"<\/p>\n

                      Question 5.
                      \nCarbon combines with other elements through the _______ bond.
                      \nlnaocvet
                      \nAnswer:
                      \nCovalent<\/p>\n

                      Question 6.
                      \nPlastics made of________ are represented by resin code #6.
                      \nsytlopynere
                      \nAnswer:
                      \nPolystyrene<\/p>\n

                      Question 7.
                      \nOne-time use plastics are also known as ______ plastics.
                      \n\u00e1wyrhotwa
                      \nAnswer:
                      \nthrowaway<\/p>\n

                      \"<\/p>\n

                      Question 8.
                      \nOne-time use plastics cause ________ damage.
                      \ntrnvomenialne
                      \nAnswer:
                      \nEnvironmental<\/p>\n

                      Question 9.
                      \nExpanded polystyrene is commercially known as
                      \nmthreolco
                      \nAnswer:
                      \nThermocol<\/p>\n

                      \"<\/p>\n

                      VII. Very Short Answer questions :<\/span><\/p>\n

                      Question 1.
                      \nHow can graphite be transformed to diamond?
                      \nAnswer:
                      \nGraphite could be transformed to the diamond at high temperature and high pressure.<\/p>\n

                      Question 2.
                      \nHow did the ancients obtain charcoal?
                      \nAnswer:
                      \nAncients manufactured charcoal by burning organic compounds.<\/p>\n

                      Question 3.
                      \nWhich theory was challenged by the synthetic preparation of Urea?
                      \nAnswer:
                      \nVital force theory.<\/p>\n

                      \"<\/p>\n

                      Question 4.
                      \nName two inorganic carbon compounds which are used as an antacid?
                      \nAnswer:
                      \nCalcium carbonate (CaCO3<\/sub>), Sodium bicarbonate (NaHCO3<\/sub>)<\/p>\n

                      Question 5.
                      \nWhat is tetravalency?
                      \nAnswer:
                      \nCarbon has the tendency to share~its four electrons with other atoms to complete its octet. This is called Tetravalency.<\/p>\n

                      Question 6.
                      \nName the primary factor that determines the physical and chemical properties of compounds.
                      \nAnswer:
                      \nNature of bonding in a compound.<\/p>\n

                      \"<\/p>\n

                      Question 7.
                      \nWhy do elements show allotropy?
                      \nAnswer:
                      \nIt’s a method of formation or preparation.<\/p>\n

                      Question 8.
                      \nWhy is graphite softer than a diamond?
                      \nAnswer:
                      \nThe hexagonal layers in graphite are held together by weak Vander Waals forces of attraction.<\/p>\n

                      Question 9.
                      \nWhat are Polymer resins?
                      \nAnswer:
                      \nPlastics, made from long-chain organic compounds, are called \u201cPolymer resins\u201d.<\/p>\n

                      \"<\/p>\n

                      Question 10.
                      \nList the three unsafe plastics.
                      \nAnswer:<\/p>\n

                        \n
                      1. Polyvinyl chloride (PVC)<\/li>\n
                      2. Polystyrene (Thermocol)<\/li>\n
                      3. Polycarbonates (PC).<\/li>\n<\/ol>\n

                        Question 11.
                        \nHow many valence electrons are there in carbon?
                        \nAnswer:
                        \nThere are 4 valence electrons in carbon, out of 6 total electrons.<\/p>\n

                        Question 12.
                        \nWho is called \u2018Father of Modern Organic Chemistry\u2019?
                        \nAnswer:
                        \nFriedrich Wohler is called the \u2018Father of Modern Organic Chemistry\u2019.<\/p>\n

                        \"<\/p>\n

                        Question 13.
                        \nWhich three resin codes are unsafe?
                        \nAnswer:
                        \nResin Code Nos. 3, 6, and 7 unsafe.<\/p>\n

                        VIII. Short Answer questions:<\/span><\/p>\n

                        Question 1.
                        \nProve that a diamond is a pure form of carbon?
                        \nAnswer:<\/p>\n

                          \n
                        • When an equal weight of charcoal and diamond were burned, they produced the same amount of carbon dioxide.<\/li>\n
                        • So like charcoal, diamond is also a pure form of carbon.<\/li>\n<\/ul>\n

                          Question 2.
                          \nWrite the classification of carbon compounds.
                          \nAnswer:<\/p>\n\n\n\n\n
                          1. Organic Carbon Compound<\/td>\n2. Inorganic Carbon Compounds<\/td>\n<\/tr>\n
                          These are the compounds of carbon obtained from living organisms such as plants and animals.
                          \n(e.g) Cellulose, Ethanol, Starch.<\/td>\n                          		These are the compounds containing carbon but obtained from non-living matter.
                          \n(e.g) Calcium carbonate, Carbon dioxide, Carbon monoxide<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                          Question 3.
                          \nWrite short notes on the carbon cycle.
                          \nAnswer:<\/p>\n

                            \n
                          1. The carbon cycle is the biogeochemical cycle.<\/li>\n
                          2. Carbon is exchanged among the biosphere, geosphere, hydrosphere, and atmosphere of the Earth.<\/li>\n
                          3. Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone.<\/li>\n<\/ol>\n

                            \"<\/p>\n

                            Question 4.
                            \nDefine: (i) Allotropy (ii) Allotrope
                            \nAnswer:
                            \n(i) Allotropy: It is a property by which an element can exist in more than one form that is physically different and chemically similar.
                            \n(ii) Allotrope: The different forms of an element.<\/p>\n

                            Question 5.
                            \nDifferentiate crystalline and amorphous forms of allotropes of carbon.
                            \nAnswer:<\/p>\n\n\n\n\n\n\n\n
                            Crystalline allotropes of carbon<\/td>\nAmorphous allotropes of carbon<\/td>\n<\/tr>\n
                            1. Diamond<\/td>\n1. Charcoal<\/td>\n<\/tr>\n
                            2. Graphite<\/td>\n2. Lampblack<\/td>\n<\/tr>\n
                            3. Fullerene<\/td>\n3. Coke<\/td>\n<\/tr>\n
                            4. Graphene<\/td>\n4. Gas Carbon<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                            Question 6.
                            \nWhy is carbon monoxide harmful to health? (or) What happens when we breath Carbon monoxide?
                            \nAnswer:<\/p>\n

                              \n
                            • On exposition, carbon monoxide (CO) enters the human body through breathing.<\/li>\n
                            • It affects the function of hemoglobin by displacing oxygen from hemoglobin.<\/li>\n
                            • It will lead to death.<\/li>\n<\/ul>\n

                              \"<\/p>\n

                              Question 7.
                              \nWhy. do we remove plastics safely? How can it be done?
                              \nAnswer:<\/p>\n

                                \n
                              • Plastics are non-biogradable.<\/li>\n
                              • Plastics can be recycled (or) disposed safely without harming environment.<\/li>\n<\/ul>\n

                                Question 8.
                                \nMention two reasons for the harmful nature of plastics.
                                \nAnswer:<\/p>\n

                                  \n
                                1. Plastics contain chemicals that are harmful to our health.<\/li>\n
                                2. Most of the plastics are one-time use (or) throwaway in nature and pollutes the environment.<\/li>\n<\/ol>\n

                                  Question 9.
                                  \nGive some examples of one-time-use plastic.
                                  \nAnswer:<\/p>\n

                                    \n
                                  • Plastic carry bags,<\/li>\n
                                  • Cups,<\/li>\n
                                  • Plastic plates,<\/li>\n
                                  • Straws,<\/li>\n
                                  • Water pouches, 6. Plastic sheets.<\/li>\n<\/ul>\n

                                    \"<\/p>\n

                                    Question 10.
                                    \nWhat we can do to prevent plastic pollution?
                                    \nAnswer:<\/p>\n

                                      \n
                                    • Share scientific knowledge on plastics and their effects with our family, friends, and relatives.<\/li>\n
                                    • Create awareness to avoid harmful plastics by educating about the resin codes.<\/li>\n
                                    • Educate about the new rules to stop one-time use of plastics.<\/li>\n<\/ul>\n

                                      IX. Long Answer questions<\/span><\/p>\n

                                      Question 1.
                                      \nDraw a timeline of carbon chemistry depicting the contribution by scientists.
                                      \nAnswer:<\/p>\n\n\n\n\n\n\n\n\n\n\n
                                      Year<\/td>\nScientist<\/td>\nContribution<\/td>\n<\/tr>\n
                                      1772<\/td>\nAntoine Lavoisier (France)<\/td>\nDiamond and charcoal are carbon allotropes<\/td>\n<\/tr>\n
                                      1779<\/td>\n\u00a0Carl Scheele (Sweden)<\/td>\nGraphite is another form of carbon<\/td>\n<\/tr>\n
                                      1796<\/td>\nSmithson Tennant<\/td>\nDiamond is a pure carbon like charcoal.<\/td>\n<\/tr>\n
                                      1855<\/td>\nBenjamin Brodie (England)<\/td>\nPure graphite from carbon, proving graphite is a form of carbon<\/td>\n<\/tr>\n
                                      1955<\/td>\nFrancis Bundy (USA)<\/td>\nTransformed graphite into diamond.<\/td>\n<\/tr>\n
                                      1985<\/td>\nRobert Curl, Harry Kroto and Richard Smalley<\/td>\nDiscovered a new form of carbon called fullerenes.<\/td>\n<\/tr>\n
                                      2004<\/td>\nKostyaNovoselov Andre Geim<\/td>\nGraphene – lightest carbon<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

                                      \"<\/p>\n

                                      Question 2.
                                      \nGive an account of (I) Isomerism (II) Isomers with an illustration.
                                      \nAnswer:
                                      \n(1) Isomerism: The Phenomenon in which an element has the same molecular formula may exhibit different structural arrangement is called Isomerism.
                                      \n(II) Isomers: Compounds that have the same molecular formula but different structural formula are called isomers.
                                      \nIllustration: Molecular formula: C2<\/sub>H6<\/sub>O, is having two kinds of the arrangement of atoms as shown below.<\/p>\n

                                      \"Samacheer<\/p>\n

                                      In the above illustration, the molecular formula C2<\/sub>H6<\/sub>O has two different structural formulae
                                      \n(a) Alcohol (CH3<\/sub>CH2<\/sub>OH) [Oxygen at the end of Chain
                                      \n(b) Ether (CH3<\/sub>OCH3<\/sub>) [Oxygen at the middle
                                      \nBoth structural formulae will show different physical and chemical properties.<\/p>\n

                                      Question 3.
                                      \nWrite the salient features of Graphene.
                                      \nAnswer:<\/p>\n

                                        \n
                                      • Graphene is the most recently produced allotrope of carbon.<\/li>\n
                                      • It is honey comb-shaped hexagonal rings repeatedly arranged in a plane.<\/li>\n
                                      • It is the thinnest compound known to man at one atom thick.<\/li>\n
                                      • It is the lightest material known and the strongest compound discovered.<\/li>\n
                                      • Layers of graphene are stacked to form graphite by Vander Waals forces.<\/li>\n<\/ul>\n

                                        Question 4.
                                        \nBriefly note the harmful effects of any four plastics.
                                        \nAnswer:
                                        \n\"Samacheer<\/p>\n

                                        \"<\/p>\n

                                        Question 5.
                                        \nHow can you minimise plastic pollution by your daily practices?
                                        \nAnswer:<\/p>\n

                                          \n
                                        • Don\u2019t litter the environment by throwing plastic items.<\/li>\n
                                        • Don\u2019t burn plastics since it causes the evolution of highly toxic gases.<\/li>\n
                                        • Avoid one-time use (or) throw away plastics like plastic bags, teacups, carry bags, plastic plates, etc.<\/li>\n
                                        • Don\u2019t eat hot (or) spicy food items in plastic containers. \u2018<\/li>\n
                                        • Segregate the plastic wastes and hand this over to the municipal authorities so that it can be recycled.<\/li>\n
                                        • Know about the resin codes and avoid unsafe plastics.<\/li>\n
                                        • Don’t use thermocol for school projects.<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

                                          Tamilnadu State Board New Syllabus Samacheer Kalvi 9th Science Guide Pdf Chapter 15 Carbon and its Compounds Text Book Back Questions and Answers, Notes. Samacheer Kalvi 9th Science Solutions Chapter 15 Carbon and its Compounds 9th Science Guide Carbon and its Compounds Text Book Back Questions and Answers I. Choose the correct answer : Question …<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","enabled":false},"version":2}},"categories":[3],"tags":[],"class_list":["post-24060","post","type-post","status-publish","format-standard","hentry","category-class-9"],"jetpack_publicize_connections":[],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts\/24060"}],"collection":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/comments?post=24060"}],"version-history":[{"count":1,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts\/24060\/revisions"}],"predecessor-version":[{"id":41270,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/posts\/24060\/revisions\/41270"}],"wp:attachment":[{"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/media?parent=24060"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/categories?post=24060"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/samacheerkalvi.guide\/wp-json\/wp\/v2\/tags?post=24060"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}