Carbon and its compounds (class 10) are one of the most important topics for your board exams. Here, we have provided all the important notes of carbon and its compounds (class 10) which will help you to understand this chapter and hence excel your marks.
Basic of Carbon and Its Compounds
CARBON: Carbon is an element (non-metal)
ISOTOPES: 6C12, 6C13, 6C14
ATOMIC NUMBER: 06
ALLOTROPS: Diamond, Graphite, Fullerenes.
ATOMIC MASS: 12
VALANCE ELECTRONS: 04
OCCURRENCE OF CARBON
Carbon is found in the atmosphere inside the earth’s crust and in the living Organisms, Carbon is present in fuels like wood, coal, charcoal, coke, petroleum, natural gas, biogas, etc.
Carbon can be detected in the compounds like Carbonates and hydrogen carbonates.
Carbon is also found in the free state as Diamond, Graphite, and Fullerenes.
BONDING IN CARBON (Covalent Bond):
The atomic number of carbon is 6, and hence its electronic configuration is 2,4 with 4 valence electrons. It can attain stability by gaining 4 electrons, by losing 4 electrons, or by sharing the 4 electrons with others or by atoms.
It does not gain/take 4 electrons because it is very difficult for the 6 protons to hold the charge of 10 electrons.
It does not lose/give 4 electrons because it needs a large amount of energy to lose 4 electrons.
Therefore, it shares 4 electrons with other atoms to attain stability resulting in the formation of covalent bonds.
Note: Since a carbon atom needs 4 electrons to attain stability, therefore its valency is 4 and it is tetravalent.
The bond formed by the sharing of electrons (between two or more atoms) is called covalent bonds. There are three types of covalent bonds based on several electron pairs to be shared.
- Single Covalent Bond
- Double covalent Bond
- Triple covalent Bond
Single Covalent Bonds: The sharing of one pair of electrons between two atoms of the same or different element resulting in the formation of a single covalent bond.
Example – Formation of single covalent bond in hydrogen molecules (H2).
Double covalent bonds: The sharing of two pairs of electrons between two atoms (of the same or different elements) resulting in the formation of a double covalent bond.
Example – Formation of double covalent bond in an oxygen molecule (02).
Triple covalent bonds: The sharing of three pairs of electrons between two atoms (of the same or different element) resulting in the formation of a triple covalent bond.
Example – Formation of triple covalent bond in Nitrogen molecule (N2).
Versatile Nature Of Carbon Atom:
Two important properties of the carbon atoms enable carbon to form an enormous number of compounds. These properties are:
- Catenation: The property of the carbon atom to form a bond with another atom of carbon is called catenation. Just like carbon & silicon together form compounds with hydrogen up to seven or eight atoms of silicon.
- Tetravalency: Having a valency of 4 carbon atoms is capable of bonding with an atom of oxygen, hydrogen, nitrogen, sulfur, chlorine, and other elements.
The smaller size of the carbon atom enables the nucleus to hold the shared pair of electrons strongly, thus carbon compounds are very stable in general.
Allotropes Of Carbon:
Allotropes are the different forms of an element which has different physical properties or structure but have the same chemical properties. An element can have more than one different form.
Carbon exists in 2 types of allotropic forms which are:
- Crystalline form (Example – Diamond, Graphite, Fullerenes).
- Non-crystalline form (Example – Coal, Charcoal, and Lampblack).
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Structure Of Diamond:
In the structure of diamond, each carbon atom is bonded with the other 4 carbon atoms by strong covalent bonds to form a three-dimensional structure called Tetrahedral structure.
There is no free electron to conduct electricity. The strong covalent bond between the carbon atom makes it the world’s hardest substance.
Properties of Diamond:
Some important properties of diamond are as follows:-
- Diamond is a transparent and colorless substance with extraordinary shine due to its high refractive index.
- It is one of the hardest natural substances on earth due to its strong covalent bonds and tetrahedral structure.
- Diamond is also a very pathetic conductor of electricity because of the absence of free electrons.
- Due to its complex structure diamond has very high melting and boiling point.
- It burns on strong heating to form carbon dioxide gas.
Uses of diamond:
Uses of diamond cute as follow:-
- Diamond is used as a cutting instrument like a glass cutter, marble cutter, etc.
- It is also used in ornaments or jewelry.
- Diamond absorbs harmful radiations, hence it is used in space satellites to make radiation-proof windows.
Structure Of Graphite:
In the structure of graphite, each carbon atom is bonded with the other three carbon atoms to form hexagonal rings. These hexagonal rings combine to form a flat layer (sheet) of carbon. These layers of carbon atoms are held by weak van der Waal” forces so that these layers can slide over one another.
Since in the structure of graphite each carbon atom is bonded with the other three carbon atoms. Therefore one electron remains free to conduct electricity. Hence it is a brilliant conductor of electricity.
Properties of graphite:
Properties of graphite are as follows:
- It is a greyish-black Opaque Substance.
- It is lighter than diamond.
- It is slippery in touch.
- On strong heating graphite burns in the fire and releases CO2 (carbon dioxide).
Uses of graphite:
- Graphite is used as a solid lubricant in electric motors.
- It is used in the lid of a pencil.
- Graphite rods also have a very important use in nuclear reactors as they absorb the excess neutrons.
- It can be used in the making of graphene sheets. These sheets are said to be 100 times lighter than steel.
Fullerenes are the recently discovered allotropic form of Carbon that was prepared by H.W Kroto, Smalley, and Robert curt by the action of the laser beam on the vapour of graphite. The most commonly known fullerene contains 60 carbon atoms and is known as Buckminster fullerenes. Fullerene (C60) was
named after the American architect Buckminster Fuller because its structure resembled the framework of a dome-shaped hall, designed by fuller for the large international conference.
Structure Of Fullerene:
Fullerene (C60) seems like a football-shaped spherical molecule that contains 60 carbon atoms, that are arranged within the sort of interlinking hexagonal and pentagonal rings of carbon atoms. One C60 molecule contains 20 hexagonal rings and 12 pentagonal rings of a carbon atom.
Properties Of Fullerene:
Some important properties of fullerene are as follows:-
- These are dark solids at room temperature.
- These are not too hard and also too soft.
- On burning, fullerene only produces CO2 i.e. carbon dioxide gas.
Compounds having the same molecular formula but different structural formulas and properties are known as Isomers and this phenomenon is known as Isomerism.
- Structural Isomerism: Compounds having an equivalent formula but different structures are called Structural isomers Example: Isomers of butane (C4H10)
Series of organic compounds/elements having the same kind of functional group, chemical properties, and their successive members differ by a CH2 unit or 14 mass units are known as Homologous series.
- Characteristic of Homologous Series:
- Each successive members in a homologous series differ by CH2 unit or 14 mass unit.
- All the members of the homologous series have the same functional group.
- All the members of the homologous series display matching chemical properties.
An atom or group of atoms that are present in a molecule and largely/mainly decides the chemical properties of a compound is called a Functional Group.
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Chemical Properties of Carbon Compounds:
The important chemical properties are as follows:
- Combustion: Complete combustion of carbon compounds in the air leads to the production of carbon dioxide water, heat, and light. This is called combustion.
CH3CH2OH(l) + O2(g) → CO2(g) + H2O(l) + Heat and light
Carbon burns in air/oxygen to produce carbon dioxide, heat (energy) and light.
C(s) + O2(g) → CO2(g) + Heat and light
Saturated hydrocarbons burn with a blue flame if sufficient air or oxygen isavailable.
CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + Heat and light
In presence of a limited supply of air, saturated hydrocarbon forms a sooty flame.
Unsaturated hydrocarbons when burnt produce a yellow smoky flame.
The gas and kerosene stove used at home has an inlet for air so that, burnt to give clean blue flame.
Due to the presence of a small amount of nitrogen and sulfur, coal and petroleum produce carbon dioxide with oxides of nitrogen and sulfur which are major pollutants.
- Oxidation: Oxidation of ethanol in thepresence of oxidizers produces ethanoic acid.
- Oxidizing Agent: Some substances are capable of adding oxygen to others, which are known as Oxidising Agent.
Example: Alkaline KMnO4 (or KMnO4—KOH)
Acidified K2Cr2O7 (or K2Cr2O7—H2SO4)
KMnO4 – Potassium permanganate
K2Cr2O7 – Potassium dichromate
- Addition Reaction: The addition of dihydrogen with unsaturated hydrocarbon in the presence of catalysts such as nickel or platinum or palladium is known as a Hydrogenation (addition) reaction.
Catalyst: Substances that cause a reaction to occur or proceed at different rates without consuming in it are called a catalyst. For example; Ni, Pt, Pd, etc.
The process of converting vegetable oil into solid fat (vegetable ghee) is called the Hydrogenation of Oil.
Vegetable fats are saturated fats that are harmful to health.
Vegetable oil containing unsaturated fatty acids is good for health.
- Substitution Reaction: Replacement of 1 or greater hydrogen atoms of a natural molecule with the aid of using any other atom or group of the atom.
Substances that remove water from ethanol (alcohols) are known as Dehydrating agents. For example; Cone. H2SO4.
Uses: As a solvent, as an antiseptic (tincture iodine), as anti-freeze in automobiles.
Ethanoic Acid (CH3COOH): Commonly known as Acetic acid. This is also known that 5-8% of ethanoic acid when mixed in water is called Vinegar. The melting factor of natural ethanoic acid is 290 K and hence, it frequently freezes in very cold climates so named glacial acetic acid.
- It is a colorless, pungent-smelling liquid.
- Miscible with water in all proportions.
- Turns blue litmus to red.
Commonly, soaps are in the form of sodium or potassium salts of long-chain fatty acids.
General formula: RCOO–Na+
Ammonium and sulphonate salts of long-chain fatty acids are referred to as Detergent.
Hard and Soft Water:
Water, that doesn’t produce lather with cleaningsoap with ease is known as Hard water and which produces lather with cleaning soap is known as Soft Water
The hardness of water is due to the presence of bicarbonates, chlorides, and sulfate salt of calcium and magnesium.
Advantage of Detergents: The principal gain of detergent over soaps is that soaps can’t be utilized in tough water for laundry due to the fact tough water reacts with cleaning soap to shape curdy white precipitate referred to as Scum
Cleansing Action of Soaps and Detergents:
Both soaps and detergents contain two parts. A large hydrocarbon element that’s hydrophobic (water-repelling) in nature and a shorter ionic element that’s hydrophilic (water-attracting) in nature.
The hydrocarbon a part of the cleaning soap molecule links itself to the oily (dust) drop and ionic stop orients itself toward the water and takes a round shape referred to as micelles. The cleaning soap micelles enable in dissolving the dust in water and washing our clothes.
I hope these notes for carbon and its compounds will help you understand the chapter better and you’ll perform well in your exams.