The Properties of The Alkanes Flashcards
What are alkanes used as?
Fuel
What is a sigma bond?
A type of covalent bond.
What is a sigma bond the result of?
The overlap of two orbitals, one from each atom.
How many electrons are involved in a sigma bond?
Two, one from each orbital.
Where is the sigma bond positioned?
On a line directly between the bonding atoms.
How many sigma bonds does each carbon atom in an alkane have?
4
What is the molecular shape of alkanes?
Tetrahedral
What is the bond angle for alkanes?
109.5 degrees
What does the sigma bond act as?
An axis around which the atoms can rotate freely.
What does the sigma bond mean for the shape of an alkane?
The shape is not rigid.
How can crude oil be separated?
By fractional distillation.
Why can alkanes be separated by fractional distillation?
There boiling points are different.
What happens as the length of the carbon chain increases?
The boiling point increases.
Why does the boiling point increase as the chain length increases?
The larger the molecule, the larger the surface area and there is therefore more surface contact so the strength of the London forces is greater. More energy is therefore required to overcome the forces.
What is the effect of branching on boiling point?
Branched isomers have lower boiling points.
