Alkanes Flashcards
What is a sigma bond
Each carbon atom is joined to four other atoms by single covalent bonds
Each carbon bond in an alkane has___
4 sigma bonds
What are the examples of sigma bonds
C-C
C-H
What shape are Alkanes
3D Tetrahedral
What is the bond angle for Alkanes
109.5 degrees
What are London forces
Hold molecules together in solids and liquids
The greater the London forces___
The higher the boiling point
London forces act__
between molecules that are close in surface contact
Why do long chained Alkanes have high boiling points
As chain length increases, the molecules have a larger surface area, so more energy is required to overcome the forces
Why are the boiling points for branched Alkanes less than straight chained Alkanes
-There are fewer surface points of contact between molecules
-Less london forces
-The branches get in the way and prevent the branched molecules getting close
-Decreasing London forces further
-Requiring little energy to overcome the forces
Why do Alkanes have a lack of reactivity
-C-C and C-H sigma bonds are strong
-C-C bonds are non polar
-Electronegativity of carbon and hydrogen are similar
In sunlight___
Alkanes react with halogens
What is radical substitution
The mechanism for the bromination of methane
What are the steps for a mechanism to take place
initiation
propagation
termination
For example of: CH4+Br2->CH3BR+HBR what happens in the initiation step
Br-Br->Br.+Br.
