Alkanes

Question 1

What are Alkanes?

Answer 1

Saturated hydrocarbons containing single C-C and C-H bonds.

Question 2

What are the single bonds called?

Answer 2

Sigma bonds

Question 3

Why is there free rotation around Sigma bond in Alkanes ?

Answer 3

Due to the direct overlap between two atoms.

Question 4

What is the general formula for Alkanes?
and what is the exemption

Answer 4

CnH2n+2
Cycloalkanes

Question 5

How many sigma bonds does each carbon form?

Answer 5

4 sigma bonds

Question 6

WHat is the shape around each carbon?

Answer 6

Tetrahedral - 109.5*

Question 7

Explain the Trend in boiling points for Alkanes.

Answer 7

-As chain length increases - the Mr increases meaning the molecule will have larger electrons - therefore Stronger London forces

Question 8

How does Branching in an Alkane affect it boiling point?

Answer 8

-No branching means molecules can closely pack together leadinng to more surface contanct
-there more London forces so higher boiling point.
-Branching weakens the induced dipole dipole forces as molecule cant pack as close therefore lower boiling points.