4.1.2 Alkane reactions

Question 1

name 3 reasons why there is a lack of reactivity in an alkane

Answer 1

1. C-H and C-C have strong sigma bonds
2. the C-C bond is polar
3. C-H have non-polar bonds
   both polar and non polar are due to its electronegativity (likelyhood to gain e-)

Question 2

when can complete combustion take place

Answer 2

when oxygen is in abundance

Question 3

general complete combustion equation

Answer 3

alkane + oxygen -> carbon dioxide + water

Question 4

how can you balance a combustion equation

Answer 4

1. balance the C and H on the product side

2. balance the O on the reactant side

Question 5

when does incomplete combustion take place. products which can be made

Answer 5

when not enough oxygen is available. makes CO or C

Question 6

2 incomplete combustion equations

Answer 6

1. alkane + oxygen -> carbon monoxide + water

2. alkane + oxygen -> carbon + water

Question 7

what thing is needed for a reaction of alkane + halogen

Answer 7

UV light

Question 8

general equation of alkane + halogen

Answer 8

alkane + halogen -> haloaklane + ( H+ halogen atom)

Question 9

what is radical subsitution

Answer 9

A reaction containing very reactive radicals

Question 10

3 steps of radical subsitution and what occurs using bromine + methane. explain what happens at each step

Answer 10

1. initiation
   this is when the halogen makes 2 radicals
   Br2 -> Br* + Br*
2. propegation
   here the radical reacts with the other reactant and this can cause 1 or 2 steps. as at first it may just make a halogen+halogen molecule and a alkane radical as it has lost a H
   Ch4 + Br* -> Ch3* + HBr
   Ch3* + Br2 -> Ch3Br + Br*
3. Termination
   here you will add any radicals to eachother so they are molecules and unreactive