Alkenes Flashcards
What is the single bond composed of?
Sigma bond
Bond enthalpy - +347
what is a C=C double bond made from
Sigma and Pi
Bond enthalpy is +612
What’s stronger C=C or C-C
C=C
What’s stronger sigma or Pi
Sigma
What’s more reactive sigma or Pi?
Pi
What’s more reactive an alkane or Alkene
Alkene
Why is there no rotation in C=C?
The pi is formers by the overlap of p orbitals
If there was any rotation the p orbitals would no longer overlap and the pi bond would break
Define Electrophile
An electron pair acceptor
Type of electrophiles
Hydrogen Halides (E.g HBr, HCl)
Halogens (Cl2, Br2)
Sulphuric acid (H2SO4)
What are alkyl groups?
Methyl, ethyl, propyl
What is positive inductive effect?
The ability to release electron density through a covalent bond
Why are tertiary carbocations more stable than primary carbocations
There is a greater positive inductive effect from 3 alkyl groups in tertiary carbocations compared to 2 alkyl groups in secondary carbons
Explain why 2-broom propane is the major product?
It’s formed from a secondary carbocations intermediate
Secondary is more stable then primary due to the positive inductive effect of the 2 alkyl groups
What’s the reagent used to test for Alkenes
Br2
Observation when alkene is present
Orange to colourless
