A Level Alkanes Flashcards Preview

Chemistry > A Level Alkanes > Flashcards

Flashcards in A Level Alkanes Deck (19)
1

What is homolytic fission?

Each of the atoms takes one of the electrons to form a radical

2

What is a radical?

Group of atoms don’t sing an unpaired e-

3

What is heterolytic fission?

One of the atoms takes both e-s forming ions

4

What are sigma bonds?

The overlap of orbitals and the sharing of 2 e-

5

What shape and bond angle are Allan Es?

Tetrahedral
109.5

6

Why do longer molecules have higher boiling points?

Greater surface area and points of contact

7

Why do branched chain isomers have lower boiling points?

1. Fewer points of contact
2. Molecules further away

8

What are the 3 stages of radical substitution?

1. Initiation
2. Propagation
3. Termination

9

What occurs in the initiation stage?

Homolytic fission of the halogen molecule caused by uv light

10

What happens in the propagation stage?

1. The halogen radical reacts with the c-h bond
2. The resultant methyl radical reacts with a halogen molecule

11

What happens in the termination phase?

Two radicals join and the reaction stops

12

What is a pi bond?

Sideways overlap of adjacent p-orbitals above and below the bonding atoms

13

What characteristics must a compound have to qualify for e/z isomerism?

1. A c=c
2. There must be 2 different groups attached to each group

14

Why are alkenes more reactive than alkanes?

1. The pi electrons are more exposed than the sigma electrons
2. The pi bond enthalpy is less than sigma

15

What is an addition reaction?

The addition of a small electrophile across the double bond

16

What conditions for hydrogenation?

Nickel catalyst, 423k

17

What conditions for halogenation?

Room temperature

18

What are the products when reacting alleges with hydrogen halides?

Haloalkanes

19

What conditions for hydration?

Steam, phosphoric acid