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CARBON AND ITS COMPOUNDS (A)CARBON

CHAPTER-12
CARBON AND ITS COMPOUNDS
(A)CARBON
Text Book Question and Answers
I. Answer the following
1. What is allotropy?
Elements occurring in different form with the same chemical property but different physical properties is known as allotropy
2. Name the crystalline allotropic forms of carbon.
Diamond, Graphite.
3. Why are carbon – based compound lumped together as a separate subject within the study of chemistry?
Carbon is a unique element. Its ability to connect with other carbon atoms through strong and stable covalent bonds sets it apart from other elements. Carbon forms an exceptionally large number of compounds because of its unique characteristics like catenation, tetravalency and isomerism.
4. Will carbon as an atom interact with other atoms to form ioinc or covalent bonds?\
Covalent bonds
5. What is the total number of electrons present in a carbon atom?
six
6. Write the electronic configuration of carbon atom when it is in ground state?
1s2 2s2 2px1 2py1 2pz0
7. Write the excited state electronic configuration of carbon atom .
1s2 2s1 2px1 2py1 2pz1
8. Define organic chemistry.
Organic chemistry is a branch of chemistry that deals with carbon and its compounds.
9. Write a short note on significance of chemistry.
Organic chemistry is the most active and important field of chemistry at the moment, due to its extreme applicability to both bio-chemistry and petro-chemistry, organic compounds used as dyes, flavor's, detergents, perfumes, cosmetics have made life more colourful and comfortable


II. Fill in the blanks
1. The natural of chemical bond present in organic compounds is Covalent bond
2. The valency of carbon atom is 4
3. The ability of carbon atoms to link together to form short or long chain by covalent bond is calledCatenation
4. The first organic compound which was synthesized from inorgnic compounds was Urea
5. The person who synthesized urea from ammonium cyanate was Friedrich Wohler

III. Choose the most appropriate answer from the four alternative given.
1. Friedrich Wohler prepared the organic compound
(a)vegetable oil (b)urea (c)sucrose (d)calcium phosphate
Answer:(b) Urea
2. The unique property of carbon atom is
(a)forming covalent bond (b)semiconductivity
(c)catenation, tetravalency and isomerism (d)forming ioinc bond
Answer:(c) catenation, tetravalency and isomerism
3. The following is an organic compound
(a)calcium carbonate (b)sodium bicarbonate (c)carbon dioxide (d)citric acid
Answer:(d) citric acid
4. The organic solvent is
(a)water (b)hydrogen peroxide (c)hydrochloric acid (d)carbontetrachloride
Answer:(d) Carbontetrachloride

5. Hydrocarbons are the compounds of
(a)C,H,O (b)C,H (c)H, CO2 (d)CO2, H2O
Answer:(b) C, H.


IV. Answer the following questions
1. Distinguish between organic and inorganic compound
Organic compoundInorganic compound
Many are gases, liquid and solidsMost are solids
Low Melting point and Boiling pointHigh Melting point and Boiling point
Forms covalent bondsForms ionic bonds
Mainly insoluble in water, mainly soluble in organic solventsMainly soluble in water, mainly insoluble in organic solvents
Almost all burnVery few burn
Reaction are slowReaction are fast
Homology and isomerism commonHomology and isomerism not common

2. Make a list of five organic and five inorganic compound used in our daily life.
Organic Compound:
a) Citric acid used for preservative
b) Methane used as a fuel
c) Sugar used in food products
d) Aspirin used as a medicine
e) Ethyl alcohol used in hard drinks and some medicines
f) Octane used as automobile fuel
g) Phenol used in antiseptic
h) Acetic acid used in pickles and other food preparations
Inorganic Compound:
a) Sodium carbonate
b) Sodium bicarbonate
c) Sodium chloride
d) Water
e) Calcium carbonate
f) Oxygen
g) Potassium
3. Organic compounds are formed under some vital force. Say true or false. Explain.
It was believed by scientists that organic substances could be only formed under the influence of the vital force in the bodies of animals and plants. Wohler’s synthesis the organic compound in the lab artificially and proved that view is false
4. Name three typical organic compounds commonly present in our food.
Carbohydrates, proteins and lipids
5. Describe catenation by giving suitable example.
Carbon develops link with carbon atoms forming a chain, this phenomenon is called catenation.
Catenation is of three ways.
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6. Why was vital force theory rejected?
Wholer’s was first person to synthesis organic compound artificially till that it was believed that organic compounds can only be synthesized in living beings by a vital force. Hence vital force theory is rejected
7. What is isomerism? Give an example.
The compounds having same molecular formula but different structural formula are called isomers and the phenomenon is called isomerism
Eg:-Butane (C4H10)
clip_image004
V. Match the following.
1. Compound containing carbon – Organic compound
2. First synthesized organic compound - Urea
3. A property of carbon
Advertisement
atom – Catenation

Additional Question and Answers
1. What is carbon? Name its Symbol, Atomic number and Atomic mass number.
Carbon is the 1st member of group 14. It has four electrons in its outermost orbit, so its valency is four and it is non-metal
Atomic symbol:-C
Atomic number (Z):-06
Atomic mass number (A):-12
2. Define covalent bond.
A chemical bond formed between two atoms due to sharing of electrons is called covalent bond.
3. Explain the importance of carbon in our lives.
Carbon is found everywhere in our lives. The food that we eat contains carbon atoms and compounds of carbon. The fuels that we use have carbon atoms in them. The paper we use, the medicines we consume, the clothes we wear, the soaps and detergents that we use, plastics and polymers that we employ to meet our needs are made of carbon atoms. The life itself on earth is carbon-based. Carbon constitutes the most essential component of all living systems. It is impossible to think of life without carbon. The search for the presence of extra-terrestrial life hinges on the discovery of the presence of compounds of carbon.
4. You might have observed chapatti or roti getting charred when overheated, give reason?
Because they have carbon content
5. When you heat sand, it doesn’t get charred why?
The molecular formula of sand is SiO, it does not contain carbon content so it doesn’t get charred
6. CaCOcontain carbon do not get charred when heating why?
Although CaCO3 contain carbon but it does not contain C-C & C-H bond, so it do not get charred when heating
7. Define allotropism? Name the two allotropes forms of carbon?
The same element exists in two or more physical forms but having same chemical properties is called allotropes of that element and the phenomenon is called allotropism
Carbon has 2 allotropic forms namely
a) Amorphous eg: Smoke, coal etc
b) Crystalline eg: - Diamond, Graphite etc
8. Why are the physical properties of diamond and graphite so different?
It’s because of the arrangement of carbon atoms different in both diamond and graphite
9. List any three differences between the physical properties of diamond and graphite.
DiamondGraphite
1. Diamond is a hard substance.
2. Density of diamond is higher than that of graphite.
3. Diamond is a bad conductor of electricity.
1. Graphite is soft.
2. Density of graphite is lower than that of diamond.
3. Graphite is a good conductor of electricity

10. What is “Buckminster fullerene”? And why it is called so?
It is an allotrope of carbon that was discovered in 1985, contains 60 carbon atoms is called as “Buckminster fullerene”. It is so called because the structure resembles the domes structure constructed by an architect Buckminster Fullerene
This Fullerene was discovered by:-Robert curl, Harold kroto and Richard smalley
11. Which property of carbon to form an almost infinite number of compounds?
Catenation, tetravalency and isomerism
12. Define Catenation.
The ability of carbon atom to have covalent links with its own atoms forming a chain is called catenation.
13. Define Chemical bond.
The attraction between two or more atoms when they chemically unite is called a chemical bond.
14. Define tertravalency.
Valency equal to four is called tetravalency.
15. Why compounds like B-B, Si-Si, and S-S do not exist in nature?
It’s because these compounds are more unstable when compare to carbon compounds
16. What is the bond angle of Methane?
10928
17. Simplest hydrocarbon Methane, Ethane and Propane have no isomers. Give reasons?
It is because there are no possibilities for branching of C-C chain
18. Explain Tetravalency of carbon
The carbon atom due to its tetravalency, can be bonded to other carbon atoms by forming single, double or triple bonds. Therefore chains of carbon atoms may be linear, branched or cyclic.
clip_image006
19. Compounds like calcium carbidecarbon monoxide, carbon dioxide, calcium carbonate etc., are considered as inorganic compounds although they have carbon atoms in their molecule. Give reason.
Some compounds of carbon do not contain either C-H group or C-C group in their molecule. Secondly, the properties of these compounds resemble those of inorganic compounds rather than organic compounds. Hence such compounds are considered to be inorganic
20. Who was the first to suggest the classification of chemical compounds into inorganic compounds and organic compounds?
J.J. Berzelius suggested the classification of chemical compounds into two categories: (i) inorganic compounds, and (ii) organic compounds.
21. Why are the compounds of carbon studied as a separate branch of chemistry?
Carbon has innumerable compounds. The number of compounds of carbon exceeds those of other elements. Many more compounds of carbon are being added to the list almost every day. Secondly, the properties of carbon compounds are different from those of others. This is why compounds of carbon are studied under a separate branch of chemistry called 'organic chemistry’.
22. Who suggested that organic compounds are those which are obtained from living sources?
Berzelius suggested the name organic compounds for those which were derived from plant or animal origin.
23. Explain the vital force theory about organic compounds.
Berzelius put forward a theory in 1827 to account for the formation of organic compounds. This theory is popularly known as 'vital force theory’. According to the theory, organic compounds are produced inside living systems under the influence of a vital force. It was thought that the vital force could not exist outside living systems and hence organic compounds could not be synthesized in the laboratory from inorganic sources.
24. Name the first organic compound obtained from an inorganic source in the laboratory. Who synthesized it?
Urea was the first organic compound synthesized in the laboratory from an inorganic compound called ammonium cyanate. This was synthesized by Friedrich Wohler in 1828.
NH4Cl + AgCNO ------> NH4CNO(ammonium cyanate) ---heat--> NH2-CO-NH2(Urea)
25. List five industries which produce organic compounds.
The industries that produce organic compounds include food industry, petro-chemical industry, pharmaceutical industry, soap industry, fertilizer industry and polymer industry.
26. Write a short note on the importance of organic compounds in our lives.
We are living in a world which is largely shaped by organic compounds. The major constituents of our food namely the carbohydrates, proteins and lipids are organic compounds. The clothes we wear of wool, cotton, leather and synthetics involve the use of organic compounds. The commodities we use such as wood, plastic, polymers such as PVC, pesticides etc., are made from organic compounds. The sources of our primary energy which include petroleum, natural gas, and coal contain organic compounds in one form or the other. Most of the antibiotics, synthetic drugs, natural and synthetic rubber, dyes, perfumes, cosmetics, soaps, detergents and plastics are products of organic compounds. Organic compounds are of vital importance to us.