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Alkenes (Reactivity (Due to C=C, The bonding in C=C is made up of 2…
Alkenes
Reactivity
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Evidence is bond energies. C-C is 364kJ/mol so C=C should be 692KJ/mol. But the actual bond energy of C=C is 610KJ/mol - it is weaker than it should be.
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Geometric isomers
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But-2-ene has 2 different geometric isomers. Around the double bond there could be hydrogens on the same side which is called a cis isomer. Therefore it would be called cis-but-2-ene. If the hydrogens are on opposite sides then its a trans isomers. Therefore it would be trans-but-2-ene.
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Trans isomers also has a different naming system for more complex alkenes which is the E (from German word entegen which means opposite). Works by calculating atomic mass. The heaviest atomic mass has a higher priority, if they are on opposite sides then it is and E isomer
Cis isomers aslo have a different naming system for more complex alkenes which is Z (from the German word zusammen which means opposite). Works the same way as an E isomer but if the highest priority groups are on the same side then it is a Z isomer.
Reactions with alkenes
Using limonene, molecular formula: C10H16
Combustion- orange flame, smokey
Oxidation using potassium permanganate and sulphuric acid- purple to brown and then brown to colourless
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18M sulphuric acid-dark residue, exothermic, release of gas
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