Properties of Alkanes Flashcards
Based off the OCR A Level Chemistry pages.
What is a hydrocarbon?
A molecule with only hydrogen and carbon chains in it
What kind of a hydrocarbon are Alkanes?
Saturated hydrocarbons
Why aren’t hydrocarbons very reactive?
Because they’re relatively stable molecules
What are alkanes’ general formula?
C n H 2n+2
What are the bonds in alkanes?
Sigma Covalent Bonds
How are Sigma Bonds formed?
The overlapping of one orbital from either bonding atom
Where is the Sigma Bond positioned?
Directly in between two atoms (due to the electron sharing)
What is the shape of alkanes?
Tetrahedral
What’s the bond angle around each central atom?
109.5 degrees
What does the length of the chain do to the alkane’s boiling point?
The longer the alkane chain, the higher the boiling point
Why do longer alkane chains have higher boiling points?
London forces between molecules become greater when there is a larger surface area
((As London forces act between molecules that are close in contact))
How do branched isomers of alkanes’ boiling points differ from chained boiling points?
Branched alkanes have lower boiling points than their chained isomers due to branches preventing atoms coming closer together.
(Meaning there are less intermolecular forces to be overcome.)
