A1: Alkanes

Question 1

Define homolytic bond fission

Answer 1

When a covalent bond breaks and each of the bonded atoms takes one of the electrons from the bonded pair, forming two radicals

Question 2

Define radical

Answer 2

An atom or group of atoms with an unpaired electron

Question 3

Heterolytic bond fission

Answer 3

When a covalent bond breaks and one of the bonded atoms takes both electrons, forming a cation and an anion

Question 4

Reactivity of alkanes

Answer 4

Don’t react with most common reagents.
C-C and C_H have a high bond enthalpy and are very strong, and also non polar.

Question 5

Products of complete combustion

Answer 5

CO2 and H2O

Question 6

Products of incomplete combustion

Answer 6

CO and H2O

Question 7

Limitations of radical substitution

Answer 7

Further substitution can occur and at any point on the carbon chain

Question 8

Define addition reaction

Answer 8

2 reactants join together to make one product

Question 9

Define substitution reaction

Answer 9

An atom or group of atoms is replaced by another group or atom

Question 10

Elimination reaction

Answer 10

Removal of a small molecule from a large one (one reactant forms two products)

Question 11

Radical substitution steps

Answer 11

Initiation, Propagation (x2), termination (x3)

Question 12

Initiation of Methane and Bromine

Answer 12

Br-Br –> 2Br.

Question 13

Propagation for Methane and Bromine

Answer 13

1) Br. + CH4 –> .Ch3 +HBr
2) CH3. + Br –> Ch3Br + Br.

Question 14

Termination for methane and bromine

Answer 14

2Br. –> Br2
2.CH3 –> C2H6
.CH3 + .Br –> CH3Br