Alkenes Flashcards Preview

Module 4 Chemistry > Alkenes > Flashcards

Flashcards in Alkenes Deck (20):
1

Are alkenes saturated or unsaturated?

They are unsaturated hydrocarbons.

2

What is the general formula of an alkene?

CnH2n

3

What is the bonding of the carbon=carbon double bond?

Covalent.

4

When does a sigma bond form?

When two s orbitals overlap.

5

What gives the highest possible electron density between two nuclei?

The two s orbitals overlapping in a straight line, this s a single covalent bond.

6

What creates a strong electrostatic attraction between the nuclei and the shared pair of electrons?

The high electron density between the nuclei.

7

What type of bond enthalpy do sigma bonds have?

They have a high bond enthalpy.

8

What is the strongest type of covalent bond?

Sigma bonds.

9

How is a Pi bond formed?

This is formed by the sideways overlap of two p orbitals.

10

How many parts does a Pi bond have?

It has two parts.

11

What are the two parts that make up a Pi bond?

One is above and one is below the molecular axis.

12

What is the shape of a p orbital?

P orbitals are dumbbell shaped.

13

Why are Pi bonds weaker than sigma bonds?

This is because the electron density is more spread out above and below the nuclei. This means that the electrostatic attraction is weaker.

14

What type of bond enthalpy do Pi bonds have?

They have a relatively low bond enthalpy.

15

What is more reactive, an alkene or an alkane?

Alkanes are more reactive because they are unsaturated.

16

What type of covalent bonds do alkanes have?

Sigma bonds only.

17

Are the bonds in alkanes polar or non-polar?

They are non-polar.

18

Why don't alkanes attract electrophiles or nucleophiles?

The bonds in alkanes are non-polar.

19

Why is the Pi bond in alkanes likely to be attacked by electrophiles?

This is because the double bond has a high electron density and the Pi bond sticks out above and below the rest of the molecule.

20

Why are alkanes useful for making other organic compounds and petrochemicals?

The double bond is so reactive and so makes a good starting point for the reaction.