ch12 Flashcards
What is the main use of alkanes?
Fuel
What is the general formula of alkanes?
CnH2n+2
What kind of covalent bonds are formed in alkanes?
Sigma bonds
What is a sigma bond?
The overlap of two orbitals
How are alkanes separated?
Fractional distillation
How does chain length effect boiling point?
Longer chain length raises boiling point
Why does chain length have that effect on boiling point?
Increased chain length
Greater surface area of contact
Stronger London forces
What is the effect of branching on boiling point?
Lowers boiling point
Why does branching have that effect on boiling point?
More branching
Less surface area of contact
Weaker London forces
What are the reasons for alkanes being fairly unreactive?
C-C and C-H sigma bonds are strong
C-C bonds are non polar
Similar electronegativity of C and H
What is the combustion reaction of an alkane in words?
Alkane + oxygen -> water + carbon dioxide
What is complete combustion?
Alkanes burn completely to produce carbon dioxide and water.
What are the two potential products from incomplete combustion of alkanes?
Carbon monoxide
Carbon
What is the name of the mechanism for bromination of alkanes?
Free radical substitution
What are the three stages of radical substitution?
Initiation
Propagation
Termination
Describe the initiation stage of radical substitution
The first step in a radical reaction where a covalent bond in a molecule is broken through homolytic
fission to create 2 radicals.
Describe the propagation stage of radical substitution
=the steps that continue a free radical reaction, in which the radical reacts with a reactant molecule
to form a new molecule and another radical causing a chain reaction.
Describe the termination stage of radical substitution
=the step at the end of a radical reaction where 2 radicals combine to form a molecule.
