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Flashcards in A Level Alkanes Deck (19)
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1
Q

What is homolytic fission?

A

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

2
Q

What is a radical?

A

Group of atoms don’t sing an unpaired e-

3
Q

What is heterolytic fission?

A

One of the atoms takes both e-s forming ions

4
Q

What are sigma bonds?

A

The overlap of orbitals and the sharing of 2 e-

5
Q

What shape and bond angle are Allan Es?

A

Tetrahedral

109.5

6
Q

Why do longer molecules have higher boiling points?

A

Greater surface area and points of contact

7
Q

Why do branched chain isomers have lower boiling points?

A
  1. Fewer points of contact

2. Molecules further away

8
Q

What are the 3 stages of radical substitution?

A
  1. Initiation
  2. Propagation
  3. Termination
9
Q

What occurs in the initiation stage?

A

Homolytic fission of the halogen molecule caused by uv light

10
Q

What happens in the propagation stage?

A
  1. The halogen radical reacts with the c-h bond

2. The resultant methyl radical reacts with a halogen molecule

11
Q

What happens in the termination phase?

A

Two radicals join and the reaction stops

12
Q

What is a pi bond?

A

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

13
Q

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

A
  1. A c=c

2. There must be 2 different groups attached to each group

14
Q

Why are alkenes more reactive than alkanes?

A
  1. The pi electrons are more exposed than the sigma electrons
  2. The pi bond enthalpy is less than sigma
15
Q

What is an addition reaction?

A

The addition of a small electrophile across the double bond

16
Q

What conditions for hydrogenation?

A

Nickel catalyst, 423k

17
Q

What conditions for halogenation?

A

Room temperature

18
Q

What are the products when reacting alleges with hydrogen halides?

A

Haloalkanes

19
Q

What conditions for hydration?

A

Steam, phosphoric acid