Fuels GapFill

The raw material for many organic compounds is  nitrocarbonphosphate rockcrude oilcarbonate lubricantviscous nitratecoarse sand, which was formed over millions of years. It is made up of mixtures of hydrocarbons, which contain alkanes with different length chains. The hydrocarbons can be separated into fractions using  fractional distillationtitrationelectrolysischromatographyfiltrationfractional combustion.

Different fractions have different uses, including solvents, lubricants, making polymers and fuels or gases. When separating the fractions, crude oil enters the column at the bottom and then  condensesevaporatesliquefiescrystallisessolidifiescongeals. Higher in the column, the temperature is  more changeablemore constanthigherlowerconstantly increasingfluctuating, so different fractions condense at different heights in the column, depending on their  energy contentboiling pointviscosityfreezing pointmelting pointentropy.

The length of an alkane chain affects the properties of that alkane. For example, a longer alkane will have a higher boiling point, and will be more  saturatedexpensiveusefulflammableefficientviscous and less  pungentunsaturatedcheapdenseflammablethermally conductive. Alkanes are often used as fuels, which involves a  combustionpolymerisationreductionfermentationslowcondensation reaction, which releases energy. The alkane reacts with oxygen to form  carbon monoxidehydrogen chloridecarbon dioxidemethanesulfuric acidenergy and water.

Longer alkanes are often  burnedcrackedcondensedmeltedpressuriseddistilled, forming shorter alkanes and  alcoholsalkenescarboxylic acidsbaseswatermetals. 

All fossil fuels are non-renewable and contain some amount of  carbonphosphorushydrogenheliumoxygensulfur. This can form a harmful gas which, along with oxides of nitrogen formed in hot engines, is responsible for many respiratory issues in people and the formation of  poison rainalkali rainpungent rainacid rainlava raintoxic rain, a pollutant which corrodes buildings and damages wildlife. Fossil fuels can also burn incompletely to produce  dimmersparticulatesradio particlesmonoxidescarbon grainssolidates, solid particles which can contribute to global dimming, and  xenonargonnitrogenhydrogen chloridehydrogencarbon monoxide, a colourless, odourless gas which is toxic to animals.