3.3.4 Alkenes

Question 1

Define electrophile

Answer 1

Electron pair acceptor in an organic mechanism. Attracted to areas with lots of electrons/ negative charge

Question 2

Why can bromine react with alkenes ?

Answer 2

Although its non-polar, it can be polarised indudcing a dipole
e- dense carbon carbon double bonds cause induced dipole in Br2

Question 3

Define racemix

Answer 3

Equal mixture of optical isomers

Question 4

Cyclohexene is prepared by the dehydration of cyclohexanol using concentrated phosphoric acid as a catalyst. Identify the factors that influence the boiling points of each of each compound. State how and why cyclohexene can be separated from the reaction mixture

Answer 4

Cyclohexene has Van der Waals forces between molecules
Cyclohexanol and phosphoric acid both have hydrogen bonds between molecules
Van der Waals forces weaker than hydrogen
So cyclohexene has a lower boiling point and can be separated by distillation

Question 5

Identify a compound used to react with SO2 in the products of combustion before they enter atmosphere + why

Answer 5

CaO/CaCO3
Neutralisation

Question 6

Stereoisomerism

Answer 6

Compounds with same structural formula but different arrangement in space

Question 7

Double covalent bond

Answer 7

Centre of high electron density