GCSE›Edexcel GCSE Chemistry›Mind mapsFuelsEdexcel GCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsCrude oilHydrocarbons: carbon and hydrogen onlyMixture of mainly alkanesA finite resource, non-renewableFractional distillationOil heated, vapour enters a columnColumn hotter at the bottomHigher boiling points condense lower downGases: heating; petrol: cars; kerosene: aircraftBitumen surfaces roadsDown the columnLonger chainsHigher boiling pointsHarder to igniteMore viscousAlkanes differ by CH₂Fuelscrude oil and hydrocarbonsCHCO₂Burning fuelsComplete: CHX4+2 OX2→COX2+2 HX2O\ce{CH4 + 2O2 -> CO2 + 2H2O}CHX4+2OX2COX2+2HX2OIncomplete gives CO and sootCO is toxic: stops blood carrying oxygenSulfur burns to SOX2\ce{SO2}SOX2 → acid rainHot engines form nitrogen oxidesCrackingSplits large alkanes into smaller moleculesMakes alkenes, which are unsaturatedDemand for short chains exceeds supplyAlkenes feed polymer makingExam tipsLink chain length to boiling point and column positionLong chains are harder to igniteHydrogen vs petrol: emissions and storage