IGCSE›Edexcel IGCSE Chemistry›Mind maps4.2 Crude OilEdexcel IGCSE Chemistry: Mind mapStudy pack PDFAlso for this subtopic:Revision notesFlashcardsSubtopic testCover factsSeparatingMixture of hydrocarbons, mostly alkanesFractional distillation uses boiling pointsColumn hotter at bottom, cooler at topLongest chains condense near the bottomFractionsGases, petrol, kerosene, diesel, fuel oil, bitumenLonger chain: darker colourLonger chain: higher boiling pointLonger chain: more viscousBurning fuelsComplete: CO2 + waterIncomplete: CO and/or sootCarbon monoxide binds haemoglobin, less oxygen carriedHot engines make oxides of nitrogenCrude oilfractions and fuelsCOSO2Acid rainSulfur impurities burn to sulfur dioxideSO2 and NOx dissolve in atmospheric moistureDamages plants, aquatic life and limestoneCrackingLong alkane → shorter alkane + alkeneHot silica or alumina catalyst, 600–700°CSupply of long chains exceeds demandAlkenes are feedstock for plasticsExam tipsGive both reasons for cracking