FUNCHEM 24 - Alkanes II

Question 1

Are all cyclic carbon compounds planar?

Answer 1

All cyclic carbon compounds after cyclopentane are puckered. If they were planar, all the hydrogens would be eclipsed resulting in steric strain, the bond angles would cause angle strain, and they would have higher energy.

Question 2

What are the names of the two conformations of cyclohexane?

Answer 2

1. Chair (have axial and equatorial hydrogens)

2. Boat (have more energy)

Question 3

What is a ring flip?

Answer 3

A ring flip is when axial and equatorial hydrogens of a chair conformation switch positions.

Question 4

What are two examples of cyclohexanes in biology?

Answer 4

1. Cholic acid is a major bile acid that emulsifies lipids, allowing their hydrolysis by pancreatic lipase.
2. Cholesterol is important for membrane structure.

Question 5

List chemical properties of alkanes.

Answer 5

1. Extremely unreactive towards strong acids, strong alkalis, mild oxidizing agents, and halogens in the dark
2. Undergoes oxidation and halogen reactions (with light)

Question 6

What happens from the oxidation/combustion of hydrocarbons?

Answer 6

The oxidation of hydrocarbons forms 1 CO2 from every carbon, 1 H2O from every two hydrogens, and heat.

Question 7

What are the four distinct steps in chlorination?

Answer 7

1. Initiation step
2. Chain-propagation (first step)
3. Chain-propagation (second step)
4. Chain-termination

Question 8

What starts a free radical mechanism?

Answer 8

Ultraviolet light or heat.

Question 9

What is a free radical?

Answer 9

Any molecule or atom that has an unpaired electron.

Question 10

What is the inductive effect?

Answer 10

A shift of electron density from an electron rich area to an electron poor area is called the inductive effect.