Page 1 of 42
ORGANIC CHEMISTRY QUESTIONS LATEST EXAM SOLVED
QUESTIONS & ANSWERS VERIFIED 100% GRADED A+
Give the names of five functional groups that contain a carbonyl (C=O) group
(5 marks)
1. aldehyde
2. ketone
3. ester
4. carboxylic acid
5. amide
What is meant by the term 'structural isomerism'?
(2 marks)
1. same molecular formula
2. different structural formula
State what is meant by the term hydrocarbon (1 mark)
1. molecule made up of hydrogen and carbon only
Each homologous series has its own general formula. State two other
characteristics of a homologous series (2 marks)
1. chemically similar
2. same functional group
Distinguish clearly between the terms positional, chain and functional
isomerism (4 marks)
1. same molecular formula
2. (position) functional group in different position
3. (chain) different carbon skeleton
4. (functional) different functional group
Draw the structural formula of three alkenes which have the formula C4H8
H H H H H CH3
\/\/\/
C=C C=C C=C
, Page 2 of 42
/\/\/\
CH3 CH3 H CH2CH3 H CH3
Give the structural formula of 2-bromo-3-methylbutane (1 mark)
CH3 Br
\/
CH3 - C - C - CH3
/\
H Br
Draw the structural formula of a positional isomer, a chain isomer and a
functional isomer of pent-2-ene and name them (6 marks)
HHHHH
\/\//
H - C - C - C - C = C 1. positional 2. pent-1-ene
/\/\
HHHH
HHH
\//
H - C - C = C - C - H 3. chain 4. methylbut-2-ene
//\
HCH
/|\
HHH
C-C
/\
C C 5. functional 6. cyclopentane
\/
C - C (with H2 on each carbon)
Draw structural formula for the structural isomers of C4H10 (2 marks)
HHHHHHH
\/\/\|/
H-C-C-C-C-HH-C-C-C-H
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/\/\/|\
H H H H H CH3 H
Give the name and draw the graphical formula of an alkene that is an isomer of
but-1-ene and that has a different carbon skeleton (2 marks)
1. methylpropene
2. CH3
|
H3C - C = CH2
Explain why 2,2-dichloro-3-methylpentane is a structural isomer of 2,2-
dichlorohexane (2 marks)
1. same molecular formula
2. different structural formula
Draw the displayed formula of 2,2-dichlorohaexane and thus deduce the
empirical formula (2 marks)
1. H Cl H H H H
\/\/\/
H-C-C-C-C-C-C-H
/\/\/\
H Cl H H H H
2. C3H6Cl
Explain the trends in the boiling points of C4H10, C5H12 and C6H14 (2 marks)
1. boiling point increases as size increases (more electrons)
2. as more van der waals forces between molecules
An oxide of nitrogen contains 25.9% nitrogen. Determine the empirical formula
(3 marks)
1. % N= 25.9 O= 74.1%
2. n N= 25.9/14=1.85 O=74.1/16=4.63
3. N2O5
Explain how NO is produced in a motor (2 marks)
1. N2 and O2 react
2. at high temperatures in the engine
Give 2 reasons why boilers are designed to ensure complete combustion (2
marks)
, Page 4 of 42
1. prevent production of carbon monoxide
2. more energy efficient
Draw the structure of two branched chain isomers of hexane and name them (4
marks)
1. 2-methylpentane 3. 3-methylpentane
2. | 4./\/\
/\/\ |
Outline the initiation, two propagation and one termination steps for the
reaction of methane with fluorine to make fluoromethane CH3F (4 marks)
I = F2 -> 2F'
P1 = F' + CH4 -> CH3' + HF
P2= CH3' + F2 -> CH3F + F'
T= CH3' + CH3' -> C2H6
Outline how different fractions are obtained by fractional distillation (4 marks)
1. crude oil is heated to vaporise it
2. (Vapour passed into fractionating) tower / column
3. top of tower cooler than bottom
4. fractions condensed at different temperatures
Give the two main types of product obtained by catalytic cracking (2 marks)
any two from:
motor fuels
aromatic hydrocarbons
branched alkanes / hydrocarbons
cycloalkanes
Write an equation for the cracking of an alkane which has nine carbon atoms
per molecule into methane, ethene and butene only (1 mark)
C9H2O -> CH4 + 2C2H4 + C4H8
Consider the following reaction
CH3CHBr + KOH > CH3CH(OH)CH3 + KBr
1) Name and outline a mechanism for this reaction
2) Name the halogenoalkane in this reaction
3) Identify the characteristic of the halogenoalkane molecule that enables it to
undergo this type of reaction
ORGANIC CHEMISTRY QUESTIONS LATEST EXAM SOLVED
QUESTIONS & ANSWERS VERIFIED 100% GRADED A+
Give the names of five functional groups that contain a carbonyl (C=O) group
(5 marks)
1. aldehyde
2. ketone
3. ester
4. carboxylic acid
5. amide
What is meant by the term 'structural isomerism'?
(2 marks)
1. same molecular formula
2. different structural formula
State what is meant by the term hydrocarbon (1 mark)
1. molecule made up of hydrogen and carbon only
Each homologous series has its own general formula. State two other
characteristics of a homologous series (2 marks)
1. chemically similar
2. same functional group
Distinguish clearly between the terms positional, chain and functional
isomerism (4 marks)
1. same molecular formula
2. (position) functional group in different position
3. (chain) different carbon skeleton
4. (functional) different functional group
Draw the structural formula of three alkenes which have the formula C4H8
H H H H H CH3
\/\/\/
C=C C=C C=C
, Page 2 of 42
/\/\/\
CH3 CH3 H CH2CH3 H CH3
Give the structural formula of 2-bromo-3-methylbutane (1 mark)
CH3 Br
\/
CH3 - C - C - CH3
/\
H Br
Draw the structural formula of a positional isomer, a chain isomer and a
functional isomer of pent-2-ene and name them (6 marks)
HHHHH
\/\//
H - C - C - C - C = C 1. positional 2. pent-1-ene
/\/\
HHHH
HHH
\//
H - C - C = C - C - H 3. chain 4. methylbut-2-ene
//\
HCH
/|\
HHH
C-C
/\
C C 5. functional 6. cyclopentane
\/
C - C (with H2 on each carbon)
Draw structural formula for the structural isomers of C4H10 (2 marks)
HHHHHHH
\/\/\|/
H-C-C-C-C-HH-C-C-C-H
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/\/\/|\
H H H H H CH3 H
Give the name and draw the graphical formula of an alkene that is an isomer of
but-1-ene and that has a different carbon skeleton (2 marks)
1. methylpropene
2. CH3
|
H3C - C = CH2
Explain why 2,2-dichloro-3-methylpentane is a structural isomer of 2,2-
dichlorohexane (2 marks)
1. same molecular formula
2. different structural formula
Draw the displayed formula of 2,2-dichlorohaexane and thus deduce the
empirical formula (2 marks)
1. H Cl H H H H
\/\/\/
H-C-C-C-C-C-C-H
/\/\/\
H Cl H H H H
2. C3H6Cl
Explain the trends in the boiling points of C4H10, C5H12 and C6H14 (2 marks)
1. boiling point increases as size increases (more electrons)
2. as more van der waals forces between molecules
An oxide of nitrogen contains 25.9% nitrogen. Determine the empirical formula
(3 marks)
1. % N= 25.9 O= 74.1%
2. n N= 25.9/14=1.85 O=74.1/16=4.63
3. N2O5
Explain how NO is produced in a motor (2 marks)
1. N2 and O2 react
2. at high temperatures in the engine
Give 2 reasons why boilers are designed to ensure complete combustion (2
marks)
, Page 4 of 42
1. prevent production of carbon monoxide
2. more energy efficient
Draw the structure of two branched chain isomers of hexane and name them (4
marks)
1. 2-methylpentane 3. 3-methylpentane
2. | 4./\/\
/\/\ |
Outline the initiation, two propagation and one termination steps for the
reaction of methane with fluorine to make fluoromethane CH3F (4 marks)
I = F2 -> 2F'
P1 = F' + CH4 -> CH3' + HF
P2= CH3' + F2 -> CH3F + F'
T= CH3' + CH3' -> C2H6
Outline how different fractions are obtained by fractional distillation (4 marks)
1. crude oil is heated to vaporise it
2. (Vapour passed into fractionating) tower / column
3. top of tower cooler than bottom
4. fractions condensed at different temperatures
Give the two main types of product obtained by catalytic cracking (2 marks)
any two from:
motor fuels
aromatic hydrocarbons
branched alkanes / hydrocarbons
cycloalkanes
Write an equation for the cracking of an alkane which has nine carbon atoms
per molecule into methane, ethene and butene only (1 mark)
C9H2O -> CH4 + 2C2H4 + C4H8
Consider the following reaction
CH3CHBr + KOH > CH3CH(OH)CH3 + KBr
1) Name and outline a mechanism for this reaction
2) Name the halogenoalkane in this reaction
3) Identify the characteristic of the halogenoalkane molecule that enables it to
undergo this type of reaction
