Alkanes

• Impurities in Earth's atmosphere react to form a weak form of H2SO4.
• Flue gas desulfurization is used to remove impurities from waste products.
• Calcium oxide and gypsum are used in the flue gas desulfurization process.
• Pollutants in the atmosphere can contribute to global warming, acid rain, and health issues in humans.
• Alkanes react with halogens in the presence of UV light to produce halogenoalkanes.
• The UV light breaks down the halogen bonds, producing reactive intermediates called free radicals.
• The reactions between alkanes and halogens involve initiation, propagation, and termination steps.
• Initiation involves the breakdown of the halogen.
• Oxides of nitrogen are also produced during alkane combustion.
• Catalytic converters use a rhodium catalyst to convert harmful products into more stable ones like CO2 or H2O.
• Incomplete combustion can produce carbon particulates, which can cause respiratory problems and air pollution.
• Sulfur impurities can lead to water acidification.
• Complete combustion of hydrocarbons produces carbon dioxide and water.
• Incomplete combustion of hydrocarbons produces carbon monoxide and water.
• Carbon monoxide is a toxic gas with no odor or color.
• Crude oil is a mixture of different hydrocarbons that can be separated by fractional distillation based on their different boiling points.
• The process involves vaporizing the mixture and feeding it into a fractionating column.
• Vapors rise, cool, and condense, with products of different chain lengths being siphoned off for different uses.
• Compounds collected from the fractionating column are broken down further via the method of cracking.
• Cracking breaks down longer hydrocarbon chains into shorter, more useful molecules.
• There are two main types of cracking: thermal cracking and catalytic cracking.
• Thermal cracking produces a high proportion of alkanes and alkenes at high temperatures and pressures.
• Catalytic cracking produces aromatic compounds with carbon rings at lower temperatures with the use of a zeolite catalyst.
• Alkanes release a lot of energy when combusted and make good fuels.
• Propagation involves the replacement of a hydrogen and the reforming of the Cl• radical as a catalyst.
• Termination occurs when two radicals join to end the chain reaction and form a stable product.
• The propagation step can continue multiple times, resulting in multiple reactions.
• Substitutions in a chain reaction can be altered to favor the termination step and limit the number of substitutions.