12) Alkanes Flashcards
(12 cards)
Define alkane.
Saturated hydrocarbons containing single C-C and C-H bonds as sigma bonds with free rotation.
What are the bond angles in alkanes?
109.5 degrees
What is the shape of the C-H bond around each carbon atom in an alkane?
120 degrees
What are sigma bonds?
Single bonds which can rotate, formed when s-orbitals overlap directly.
What are pi bonds?
Bonds which can rotate and are only found in double and triple bonds, formed when p-orbitals overlap sideways.
When are radicals formed?
When UV light breaks apart a covalent bond in homolytic fission.
What are the three steps in free radical substitution?
Initiation, propagation, and termination.
Give the formula(e) for the initiation stage of free radical substitution.
Cl2 (+hf) —> 2Cl.
What does the ‘h’ mean in the formula for the initiation stage of free radical substitution?
Planck’s constant
What does the ‘f’ mean in the formula for the initiation stage of free radical substitution?
The frequency of radiation
Give the formula(e) for the propagation stage of free radical substitution.
Cl. +CH4 —> .CH3 + HCl
.CH3 + Cl2 —> CH3Cl + Cl.
Give the formula(e) for the termination stage of free radical substitution.
.CH3 + .CH3 —> C2H6
