
Chapter - 2
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ICSE CHEMISTRY CLASS 8
Chapter: Carbon and its Compounds
Introduction to Carbon: Carbon is a versatile element that forms the basis of all living things and a vast array of organic compounds. Its unique bonding properties allow it to form a variety of molecules, making it essential for life and industry.
Key Concepts:
Tetravalency of Carbon:
Carbon has four valence electrons, allowing it to form up to four covalent bonds with other atoms.
Hydrocarbons:
Hydrocarbons are organic compounds consisting of only carbon and hydrogen atoms.
Alkanes are saturated hydrocarbons with single bonds, while alkenes and alkynes have double and triple bonds, respectively.
Functional Groups:
Functional groups are specific arrangements of atoms in organic compounds that determine their chemical properties.
Isomerism:
Isomers are compounds with the same molecular formula but different structural arrangements, leading to distinct properties.
Homologous Series:
Homologous series are groups of organic compounds with similar functional groups and successive members differing by a CH2 unit.
Nomenclature of Organic Compounds:
IUPAC (International Union of Pure and Applied Chemistry) rules are used to systematically name organic compounds.
Properties of Carbon Compounds:
Carbon compounds can be organic or inorganic, with unique properties due to the versatility of carbon bonding.
Examples of Carbon Compounds:
Alkanes:
Alkanes are saturated hydrocarbons with single bonds.
Example: Methane (CH4), ethane (C2H6).
Alkenes:
Alkenes have at least one double bond.
Example: Ethene (C2H4), propene (C3H6).
Alkynes:
Alkynes contain at least one triple bond.
Example: Ethyne (C2H2), propyne (C3H4).
Alcohols:
Alcohols have the functional group -OH.
Example: Methanol (CH3OH), ethanol (C2H5OH).
Carboxylic Acids:
Carboxylic acids have the functional group -COOH.
Example: Acetic acid (CH3COOH), formic acid (HCOOH).
Esters:
Esters are derived from carboxylic acids and alcohols.
Example: Ethyl acetate (CH3COOC2H5).
Applications of Carbon Compounds:
Energy Sources:
Fossil fuels like coal, petroleum, and natural gas are carbon compounds used for energy.
Polymers:
Polymers, such as plastics and synthetic fibers, are carbon-based compounds with diverse applications.
Medicines:
Many pharmaceutical compounds are carbon-based and play a crucial role in medical treatments.
Food and Nutrition:
Organic compounds like carbohydrates, proteins, and lipids are essential for nutrition and energy.
Environmental Considerations:
Green Chemistry:
Green chemistry focuses on developing environmentally friendly processes and reducing the environmental impact of carbon compounds.
Conclusion: The study of carbon and its compounds is fundamental to understanding the chemistry of life and the materials around us. Carbon's ability to form diverse and complex molecules makes it a central element in both biological systems and technological advancements.
Here are 15 questions and answers based on the ICSE Class 8 Chemistry syllabus for the chapter "Carbon and its Compounds":
Questions:
Q1: How many valence electrons does carbon have?
A1: Carbon has four valence electrons.
Q2: What is the term for compounds consisting of only carbon and hydrogen?
A2: Hydrocarbons.
Q3: What is the general formula of alkanes?
A3: CnH2n+2, where n is the number of carbon atoms.
Q4: Which type of hydrocarbons have at least one double bond between carbon atoms?
A4: Alkenes.
Q5: What is isomerism in organic compounds?
A5: Isomerism is when compounds have the same molecular formula but different structural arrangements.
Q6: What are functional groups in organic compounds?
A6: Functional groups are specific atom arrangements that determine the chemical properties of organic compounds.
Q7: Give an example of a carboxylic acid.
A7: Acetic acid (CH3COOH).
Q8: What is a homologous series in organic chemistry?
A8: A homologous series is a group of compounds with similar functional groups and a regular increase in the number of carbon atoms.
Q9: How are organic compounds named using IUPAC rules?
A9: IUPAC rules provide a systematic way to name organic compounds based on their structure.
Q10: Which class of organic compounds has a general formula of CnH2n?
A10: Alkenes.
Q11: What is the functional group in alcohols?
A11: -OH (hydroxyl group).
Q12: What is the role of carboxylic acids in nature?
A12: Carboxylic acids are involved in metabolic processes and are important components of living organisms.
Q13: Give an example of an ester.
A13: Ethyl acetate (CH3COOC2H5).
Q14: Which class of organic compounds contains a triple bond between carbon atoms? A14: Alkynes.
Q15: What are the main sources of carbon compounds used as energy sources?
A15: Fossil fuels such as coal, petroleum, and natural gas.
Here are 15 multiple-choice questions (MCQs) along with their answers, based on the ICSE Class 8 Chemistry syllabus for the chapter "Carbon and its Compounds":
Questions:
Q1: Which element forms the basis of organic chemistry?
a) Oxygen
b) Nitrogen
c) Carbon
d) Hydrogen
Answer: c) Carbon
Q2: How many valence electrons does a carbon atom have?
a) 2
b) 4
c) 6
d) 8
Answer: b) 4
Q3: What is the general formula of alkanes?
a) CnH2n
b) CnH2n+1
c) CnH2n+2
d) CnH2n-2
Answer: c) CnH2n+2
Q4: Which type of hydrocarbons contain at least one double bond between carbon atoms? a) Alkanes
b) Alkenes
c) Alkynes
d) Aromatics
Answer: b) Alkenes
Q5: What is the functional group present in alcohols?
a) -COOH
b) -CHO
c) -OH
d) -NH2
Answer: c) -OH
Q6: Which class of organic compounds contains a triple bond between carbon atoms?
a) Alkanes
b) Alkenes
c) Alkynes
d) Alcohols
Answer: c) Alkynes
Q7: What is the term for compounds with the same molecular formula but different structural arrangements?
a) Homologous series
b) Isomerism
c) Functional groups
d) Aromatic compounds
Answer: b) Isomerism
Q8: Which functional group is characteristic of carboxylic acids?
a) -OH
b) -COOH
c) -NH2
d) -CHO
Answer: b) -COOH
Q9: What is the systematic naming of organic compounds according to IUPAC rules called? a) Isomerism
b) Aromatics
c) Nomenclature
d) Homologous series
Answer: c) Nomenclature
Q10: Which class of organic compounds has a general formula of CnH2n?
a) Alkanes
b) Alkenes
c) Alkynes
d) Aromatics
Answer: b) Alkenes
Q11: Which type of organic compounds are involved in metabolic processes and are components of living organisms?
a) Alkanes
b) Alkenes
c) Carboxylic acids
d) Esters
Answer: c) Carboxylic acids
Q12: What is the primary source of carbon compounds used as energy sources?
a) Soil
b) Air
c) Fossil fuels
d) Water
Answer: c) Fossil fuels
Q13: Which class of organic compounds are important components of plastics and synthetic fibers?
a) Alkanes
b) Alkenes
c) Polymers
d) Carboxylic acids
Answer: c) Polymers
Q14: Which functional group is present in esters?
a) -OH
b) -COOH
c) -NH2
d) -COO
Answer: d) -COO
Q15: What does the term "homologous series" mean in organic chemistry?
a) Compounds with the same molecular formula but different structural arrangements
b) A group of compounds with similar functional groups and regular increase in carbon atoms
c) Compounds that contain hydrogen and carbon atoms
d) A group of isomers
Answer: b) A group of compounds with similar functional groups and regular increase in carbon atoms
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