A Level OCR Chemistry Module 4 (A+ GRADED)

Alkane correct answers All bonds are full so it is saturated Covalently bonded Alkane formula correct answers CnH2n+2 Alkene correct answers More reactive Double bonded carbons Unsaturated (mono) Alkene formula correct answers CnH2n Making fuel (complete combustion equation) correct answers fuel + O2 >>>>> CO2 + H2O Making fuel (incomplete combustion equation) correct answers fuel + O2 >>>>> CO + H2O Making fuel (really incomplete combustion equation) correct answers fuel + O2 >>>>> C + H2O Skeletal formula correct answers You just draw the basic backbone of the molecule Each bend is a main element Isomers correct answers Skeletal formulas with one less straight line but an extra branch Difference between straight chain and branched alkanes correct answers Straight chains are more likely to be incomplete combusted and they are harder to break due to London forces. Branched are easier to break Cracking correct answers Splits long chain alkanes into shorter chain alkanes: alkenes and hydrogen 2 main types: thermal and catalytic Increases economically important fractions Thermal cracking correct answers High temperature (700 - 1200K) High pressure (7000KPa) A carbon-carbon bond breaks and one electron from the pair goes to each carbon atom Catalytic cracking correct answers Only needs a bit of pressure 700K temperature More branched chains are made Used to make more expensive petrol e.g. of a catalyst: zeolite Dynamic equilibrium correct answers Both forward and reverse reactions are ongoing Rates of both are the same Concentrations of the components remain constant