2671775
Description
Flashcards by hannie edward, updated more than 1 year ago
|
Created by hannie edward
almost 9 years ago
|
|
| Question | Answer |
| GENERAL FORMULA FOR ALKENES | CN H2N |
| CHEMICAL PROPERTIES OF ALKENES | SAME AS ALKANES |
| WHAT KIND OF REACTION MECHANISM DO ALKENES UNDERGO? | ELECTROPHILIC ADDITION. ETHENE HAS A HIGH ELECTRON DENSITY DUE TO THE PI ELECTRONS IN THE DOUBLE BOND. THIS CAUSES THE BROMINE APPROACHING IT TO BECOME POLARIZED. A LOOSE ASSOCIATION FORMS BETWEEN ETHENE AND BROMINE. THE NEGATIVE CHARGE FROM THE DOUBLE BOND MOVES TOWARDS THE BROMINE WHILE THE ELECTRONS FROM THE BR-BR BOND MOVES TOWARDS THE NEGATIVELY CHARGED BR ATOM (HETEROLYTIC FISSION). THIS RESULTS IN THE FORMATION OF A CARBOCATION AND BR ION. THE CARBOCATION IS QUITE UNSTABLE AND RAPIDLY REACTS WITH THE BR ION. |
| COMBUSTION OF ALKENES | ALKENES BURN IN OXYGEN TO GIVE CARBON DIOXIDE AND WATER. |
| REACTION WITH HALOGEN | ALKENES REACT WITH HALOGENS UNDER NORMAL CONDITIONS TO FORM DIHALOGENOALKANE. |
| REACTION WITH HYDROGEN HALIDES | ALKENES REACT WITH GASEOUS HYDROGEN HALIDE DISSOLVED IN AN INERT SOLVENT IN THE COLD TO FORM A HALOGENOALKANE. |
| REACTION WITH HYDROGEN | GASEOUS ALKENES REACT WITH HYDROGEN GAS IN THE PRESENCE OF A FINELY DIVIDED NICKEL CATALYST ON AN INERT MATERIAL TO FORM AN ALKANE. |
| REACTION WITH WATER | ALKENES REACT WITH WATER IN THE VAPOUR PHASE AT HIGH TEMPERATURES(330C) AND PRESSURE(600ATM), IN THE PRESENCE OF PHOSPHORIC ACID CATALYST TO FORM AN ALCOHOL. |
| REACTION WITH COLD, ALKALINE KMNO4 | ALKENES REACT RAPIDLY WITH COLD, ALKALINE KMNO4 TO FORM A DIOL. THE PURPLE MANGANATE TURNS BROWN. |
| REACT WITH HOT CONCENTRATED KMNO4 | ALKENES ARE OXIDISED TO CARBONYLS THEN FURTHER OXIDISED TO CARBOXYLIC ACIDS WHEN HEATED UNDER REFLUX. OXIDATIVE CLEAVAGE OF THE DOUBLE BOND OCCURS. |
Want to create your own Flashcards for free with GoConqr? Learn more.