Organic Chemistry – Alkane/Alkene Questions
Q1. Which one of the following formulae is that of a saturated hydrocarbon? a) C
2
H
2 b) C
4
H
8 c) C
3
H
6 d) C
3
H
8
Q2. The members of a homologous series have similar: a) Physical properties and the formula of one differs from the next by –CH
2
- b) Chemical and physical properties but different structural formulae c) Chemical properties and the formula of one differs from the next member by –CH
2
- d) Formulae but different chemical and physical properties
Q3. Give the formula for an alkane having 16 carbons
Q4. Give the structural formula for propane and propene
Q5. What is the molecular formula of an alkene having 12 carbon atoms?
Q6. Define the term “isomer”. Illustrate your answer with an example.
Q7. Draw two possible isomers for C
5
H
12
Q8. Distinguish between saturated and unsaturated hydrocarbons
Q9. Which of the following could not be an alkane? a) C
3
H
8 b) C
4
H
8 c) CH
3
CH
2
CH
2
CH
2
CH
3 d) C
6
H
14
Q10. The alkane in the following group with the highest boiling point is: a) Methane b) Ethane c) Propane d) Butane
Q11. The boiling points of the homologous series of alkanes: a) Decrease with increasing molecular size b) Decrease with decreasing molecular mass c) Are all approximately the same d) Are all significantly higher than the corresponding alkenes that contain the same number of carbon atoms
Q12. Which one of the following pairs of molecules would be members of the same homologous series of hydrocarbons?
A. C
5
H
10 and C
5
H
12
.
B. C
4
H
10 and C
5
H
10
.
C. C
5
H
12 and C
8
H
18
.
D. C
4
H
8 and C
6
H
14
.

Challenge Questions - linking concepts....... (Taken from past exam papers)
Q1. Isomers are
A. molecules with the same empirical formula but different arrangements of the atoms in the molecule.
B. molecules with the same molecular formula but different arrangements of the atoms in the molecule.
C. molecules with the same empirical formula but different molecular formulae.
D. molecules that contain atoms that have the same atomic number but different mass numbers.
Q2.
0.0130 mol of an alkane had a mass of 2.21 g. The molecular formula for this alkane is:
A. C
14
H
28
.
B. C
12
H
26
.
C. C
12
H
28
.
D. C
10
H
22
.
Q3.
A 1.631 g sample of an alkane contained 7.68×10
21 molecules. i. What is the molar mass of this alkane?
(2 marks) ii. What is the molecular formula for this alkane?
(1 mark)