1 - Review all questions 1 answers /25 |
1) Draw the displayed formula for 3-bromo 2-methyl butanoic acid [1]
All bonds shown and carbons included
2) Write a balanced chemical equation for the complete combustion of ethanol [3]
C2H5OH + 3O2 à 2CO2 + 3H2O
[1] [1] [1]
3) The cracking of decane produced hexane and one other product.
Write a balanced chemical equation for this reaction. [2]
C8H18 à C6H14 + C2H4
[1] [1]
4) Write an equation showing the initiation step for the reaction between chlorine and methane.
Describe the bond breaking. [2]
Cl2 à Cl. + Cl. UV light [1]
Homolytic fission [1]
5) For the reaction in (4), write out the propagation steps [2]
Cl. + CH4 à HCl + .CH3 [1]
.CH3 + Cl2 à CH3Cl + Cl. [1]
6) For the reaction in (4), write out the termination steps [3]
7) Describe the type of reagent and mechanism for questions 4 - 6 [2]
Free radical [1] Substitution [1]
8) Describe a simple chemical test to distinguish between an alkane and an alkene.
Include any observations. [3]
Add bromine water [1]
Stays orange with the alkane [1]
Turns clear and colourless with the alkene [1]
9) Show with the aid of curly arrows the mechanism for the reaction between chlorine and ethene [5]
Dipole on chlorine [1]
Curly arrow from middle of C=C to d+ Cl [1]
Curly arrow from middle of Cl - Cl to d- Cl [1]
Correctly drawn carbocation [1]
Curly arrow from a pair of electrons on the Cl ion to the positive carbon [1]
10) Describe the type of reagent and mechanism for question 9 [2]
Electrophilic [1] Addition [1]