Overview: Carbon and its Compounds Part - 2 | Basic Science for JSS 3 PDF Download

Chemical Properties of Carbon Compounds

1) Atomic Number: The atomic number of carbons is 6.

2) Atomic Mass: Its atomic mass is 12.011 g mol-1.

3) Electronegativity: According to Pauling, the electronegativity of carbon is 2.5.

4) Boiling Point: Its boiling point is 4827o C.

5) Melting Point: Its melting point is 3652o C.

6) Density:  Its density is 2.2 g cm-3 at 20o C.

7) Ionic Radius: The ionic radius for C4- is 0.26 nm and for C4+ is 0.015 nm.

8) Van Der Waals Radius: Its Van Der Waals radius is 0.091 nm.

9) Isotopes: It has three isotopes.

10) Electronic Shell: The electron shell configuration of carbon is [He]2s22p2.

11) Energy of first ionisation: The energy of first ionisation of carbon is 1086.1 KJ mol-1.

12) Energy of second ionisation: The energy of the second ionisation of carbon is 2351.9 KJ mol-1.

13) Energy of third ionisation: The energy of the third ionisation of carbon is 4618.8 KJ mol-1.

Combustion

• It is the process of burning carbon compounds in the presence of oxygen ( air) to release CO₂ and energy in the form of heat and light.  
• Combustion is also known as burning.
• Alkanes are very good fuels because when they burn in air, they produce a lot of energy. For example, methane CH₄ is a component of natural gas .
• When methane burns in abundance of oxygen (sufficient supply of air), complete combustion takes place to produce CO₂ , H₂O and energy.
• The saturated hydrocarbons usually burn in air with a blue, non-sooty flame i.e. complete combustion takes place. But if they are burnt in limited oxygen supply, incomplete combustion takes place (a yellow and sooty flame is produced). 
• On the other hand, unsaturated hydrocarbons burn in air to produce a yellow sooty flame . However, if they are burnt in pure oxygen, complete combustion takes place.

Combustion of Methane
CH₄ + 2O₂ → CO₂(g) + 2H₂O + energy

 Substitution Reaction

• These are the reactions in which one or more hydrogens of a hydrocarbon are replaced by some other atoms like chlorine .
• Substitution reactions are a characteristic property of Saturated hydrocarbons which are otherwise quite unreactive due to the presence of only C-C single bonds , but they are able to undergo substitution reactions.

Chlorination of methane

Addition Reaction

• These reactions involve the addition of one or more hydrogen atoms to double/triple bonds . 
• Therefore, this is a characteristic reaction of unsaturated hydrocarbons . Saturated hydrocarbons don’t show addition reactions.
• For example, hydrogenation reactions .

Note: In this reaction Pd/C acts as a catalyst i.e. a substance to speed up the reaction.

Hydrogenation of Ethene

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