Alkenes Flashcards
What is the general formula for alkenes?
CnH2n
What kind of hydrocarbon are alkenes and cycloalkenes?
Unsaturated hydrocarbons
What are sigma bonds?
Covalent bonds formed when electron orbitals overlap axially (end-on)
What are pi bonds?
Covalent bonds formed when electron orbitals overlap laterally (sideways)
What bonds make up a C=C bond?
One pi bond and one sigma bond
How are pi bonds formed in C=C double bonds?
By the lateral overlap of adjacent p-orbitals
Which are stronger, sigma or pi bonds?
Sigma bonds are stronger than pi bonds
Why are sigma bonds stronger than pi bonds?
Because in pi bonds the negative electrons are further away from the positive nucleus of the carbon atoms than the sigma bonds, meaning the electrostatic attraction is weaker, and the electrons are more available and ready to react
What is an electrophile?
An electron acceptor, that is attracted to regions of high electron density
How do you hydrogenate an alkene to an alkane?
H2 + heat + nickel catalyst
How is hydrogenation of alkene’s double bonds used in manufacturing?
It is used in the manufacture of margarine, as converting the C=C to C-C bonds converts vegetable oil into a solid (margarine)
What does the halogenation of alkenes form?
Di-halogenoalkanes
How do you halogenate an alkene?
X2 (e.g. Br2 or Cl2)
How do you hydrate an alkene?
Steam + Phosphoric acid catalyst
What does the hydration of alkenes form?
Alcohols
