chemistry edexcel igcse

• Hydrocarbon is a compound of hydrogen and carbon only
• Organic molecules can be represented using empirical formulae, molecular formulae, general formulae, structural formulae, and displayed formulae
• Terms to know: homologous series, functional group, and isomerism
• Compounds can be named using the rules of International Union of Pure and Applied Chemistry (IUPAC) nomenclature
• Students should be able to name compounds containing up to six carbon atoms
• Possible structural and displayed formulae of an organic molecule can be written given its molecular formula
• Reactions of organic compounds can be classified as substitution, addition, and combustion
• Crude oil is a mixture of hydrocarbons
• Fractional distillation separates crude oil into fractions like refinery gases, gasoline, kerosene, diesel, fuel oil, and bitumen
• Main fractions obtained from crude oil have different properties like color, boiling point, and viscosity
• A fuel is a substance that, when burned, releases heat energy
• Complete combustion of hydrocarbons with oxygen produces carbon dioxide and water
• Incomplete combustion can produce carbon monoxide, which is poisonous as it affects the capacity of blood to transport oxygen
• In car engines, high temperatures allow nitrogen and oxygen from air to react, forming oxides of nitrogen
• Combustion of impurities in hydrocarbon fuels can lead to the formation of sulfur dioxide
• Sulfur dioxide and oxides of nitrogen contribute to acid rain
• Long-chain alkanes can be converted to alkenes and shorter-chain alkanes by catalytic cracking
• Cracking is necessary to meet the demand for different fractions
• Alkanes are saturated hydrocarbons with the general formula CnH2n+2
• Alkanes can react with halogens in the presence of ultraviolet radiation, limited to mono-substitution
• Alkenes contain the functional group >C=C< and are classified as unsaturated hydrocarbons
• Reactions of alkenes with bromine produce dibromoalkanes
• Bromine water can be used to distinguish between an alkane and an alkene
• Addition polymers are formed by joining up many small molecules called monomers
• Repeat units of addition polymers like poly(ethene), poly(propene), poly(chloroethene), and (poly)tetrafluoroethene can be drawn
• Structure of a monomer can be deduced from the repeat unit of an addition polymer and vice versa
• Problems in the disposal of addition polymers include their inertness, inability to biodegrade, and the production of toxic gases when burned