2.1 Carbon Compounds

Organic and inorganic compounds
■ Carbon compounds

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Compounds that contain the element carbon.

■ This video contains information on the organic and inorganic compound.

■ In general, carbon compounds can be classified into two main classes

	►	Organic compounds
	►	Inorganic compounds.

■ Organic Compounds

	►	Compounds having one or more atoms in its structure.
	►	The carbon atoms in organic compounds are covalently bonded to other elements such as hydrogen, oxygen and nitrogen.
	►	Originate from living organism such as plants and animals.
	►	Examples of organic compounds and its contents: Organic compounds Elements in the organic compounds Hydrocarbon Carbon, hydrogen Carbohydrates, fats, alcohol, esters, carboxylic acids Carbon, hydrogen, oxygen Protein, amino acid Carbon, hydrogen, oxygen, nitrogen Soap Carbon, hydrogen, oxygen, sodium or potassium Detergent Carbon, hydrogen, chlorine, potassium, sulphur, sodium

■ Inorganic Carbon Compounds

	►	Carbon compounds that do not originate from living organism.
	►	Examples of inorganic carbon compounds: carbon dioxide (CO2), potassium carbonate (K2CO3) etc.

Hydrocarbon
■ Hydrocarbon

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An organic compound consisting of carbon and hydrogen.

■ This video contains information on the hydrocarbon.

■ Bonding in hydrocarbon

	►	All carbon and hydrogen atoms in the hydrocarbon molecules bonded by covalent bonds.
	►	Single bonds Double bond Triple bond
	►	Each hydrogen atom in the hydrocarbon molecules is bonded to a carbon atom through a single covalent bond.

■ Types of hydrocarbon

	►	Saturated hydrocarbons ○ A hydrocarbon that all the atoms bound to each other through a single covalent bonds.
	►	Unsaturated hydrocarbons ○ A hydrocarbon containing at least one double covalent bonds between carbon atoms.

■ Properties of hydrocarbon

	►	All the hydrocarbons do not mix with water.
	►	Melting point, boiling point and hydrocarbon density increases gradually with increasing relative molecular mass and the number of carbon atoms in the molecule.
	►	The nature of hydrocarbons physics at room temperature and pressure change from gas to liquid and finally solid line with the increasing relative molecular mass and the number of carbon atoms in each molecule.
	►	Burns completely in excess air to produce CO2 gas, water and energy as the following examples: CH4(g) + 2O2(g) → CO2(g) + 2H2O(l) + energy

■ Source of carbon compound

	►	Apart from living things, petroleum (or also known as crude oil) is another source of carbon compounds essential. ○ Petroleum exists in the state of nature as the mineral oil in the layers of the earth's crust. ○ When the remnants of the plants and animals broken down by bacteria for millions of years under the high pressure and temperature, residue is turned into petroleum as a black oil.
	►	In fact, petroleum consists of a complex mixture of hydrocarbons consisting of small molecules to large size.

■ Petroleum fractional distillation.

	►	Hydrocarbon of different molecular sizes have different boiling points.
	►	Hydrocarbon can be separated by using fractional distillation.
	►	In fractional distillation, hydrocarbons consisting of small molecule size are distilled out at low temperatures followed by larger molecules at higher temperatures. Product Range of boiling points Fraction Uses Petroleum gas below 25℃ CH4-C4H10 Fuels and various chemicals Naphtha 30℃ - 100℃ C5H12-C7H6 As raw material in the chemical industry Petrol 40℃ - 180℃ C5H12-C12H26 As a motor vehicle fuel and organic solvents Kerosene 190℃ - 250℃ C8H18-C12H20 As fuel for cooking and jet planes Diesel 250℃ - 300℃ C15H12-C25H52 Diesel fuel Lubricant 300℃ - 400℃ C20H42 As a lubricant for the motor and machinery Bitumen above 400℃ Large hydrocarbon molecules To build roads, pipelines coat groundwater

Homologous series
■ Homologous series

	►	A series of compounds with a similar general formula, usually varying by a single parameter such as the length of a carbon chain.
	►	All members of a homologous series have a functional group that determines their chemical properties.

■ This video contains information on the homologous series.

■ Functional groups of homologous series

	►	A group of molecules or atoms that take part in a chemical reaction.
	►	The following animation shows the functional groups of several homologous series.

■ Properties of the homologous series

	►	Homologous series General formula Alkane CnH2n+2 Alkene CnH2n Alcohol CnH2n+1OH Carboxylic acid CnH2n+1COOH Ester CnH2n+1COOCmH2m+1
	►	Represented by a general formula that allows the molecular formula of a member of the same homologous series be predicted.
	►	Each member differs from the previous(or next) with relative molecular mass quantity and a fixed number of atoms. ○ For example: When descending a homologous series of alkanes (CnH2n+2), each member differs from that before or after by the -CH2 group (one atom 2 atom C and H) give the relative molecular mass difference of 14 units as follows:
	►	When descending a homologous series, the members showed a gradual physical properties change. ○ For example: Melting point, boiling point, density and physical state change gradually when going down the same homologous series.
	►	Each member of the same homologous series has similar chemical properties.

■ This video contains information on the nomenclature of carbon compounds.

Formula for organic molecules
■ Molecular formula of the compound

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Shows the actual number of the atoms of the elements that combine to form the compound.

■ Structural formula

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Shows how the type of atom and bonds are arranged in the molecular structure of a compound.

■ Differences between molecular formula and structural formula

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Compound Molecular formula Structural formula Methane CH4 Ethane C2H6

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