Zusammenfassung der Ressource
OCR - A-Level -
Chemistry -
Alkanes and
Alkenes (with
bonding)
- S-orbitals have
sigma bonds
between them
- In sigma bonds, the
overlap region of the
electron orbitals lies
directly between the
two nuclei
- Alkanes are non-polar (the
polarity due to the differing
electronegativities of carbon
and hydrogen is negligible)
- This is the case for all alkanes
- Double bonds are
stronger than
single bonds, but
are not double the
strength
- The intermolecular
forces for alkanes are
London dispersion forces
(temporary dipole)
- The boiling point of
alkanes and alkenes
increases as the
length of the carbon
chain increases.
- There are more
bonds to break, so
more energy is
required to do so.
- Branched
hydrocarbons have
lower boiling points
than straight-chain
hydrocarbons.
- There is more contact
surface area between
molecules, so more van der
Waals forces. As a result,
more energy is needed to
break this.
- P-orbitals have
pi bonds
between them
- In pi bonds, the
electron orbital
overlap regions lie off
to the side of the line
connecting two nuclei