CAIE IGCSE Chemistry 11.5 Alkenes Questions

Practise alkene reactions and tests by using C=C bonding, cracking equations, bromine water and addition-product reasoning.

Exam points

use C=C and bromine water decolourisation to recognise unsaturated compounds
complete cracking equations that form alkenes, hydrogen or smaller alkanes
explain addition reactions from a single product and a reacting carbon-carbon double bond

Covered syllabus points

11.5.1—Bonding in alkenes includes a double 11.5.2—Manufacture of alkenes and hydrogen by 11.5.3—Reasons for the cracking of larger 11.5.4—Test to distinguish between saturated 11.5.5—In an addition reaction only one 11.5.6—Alkene addition reactions with

[Maximum number: 1]

38 P, Q, R and S are four organic compounds.
P is an unsaturated hydrocarbon.
Q burns but otherwise is unreactive.
R contains a C-C single bond and a C=C double bond.
S undergoes addition polymerisation.
Which compounds are alkenes?

P and R only

P, R and S

P, Q and S

Q, R and S

[Maximum number: 1]

Many organic compounds contain carbon and hydrogen only.

Propene, $\mathrm{C}_{3} \mathrm{H}_{6}$ , can be produced by heating $\mathrm{C}_{11} \mathrm{H}_{24}$ . The products of the reaction are propene, hydrogen and one other product in a 1: 1: 1 mole ratio.

Complete the symbol equation for this reaction.

\mathrm{C}_{11} \mathrm{H}_{24} \rightarrow \mathrm{C}_{3} \mathrm{H}_{6}+\mathrm{H}_{2}+

$\mathrm{C}_{8} \mathrm{H}_{16}$

[Maximum number: 1]

Which compound rapidly decolourises aqueous bromine?

propane

propanoic acid

propanol

propene

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Covered syllabus points

Question 1

Question 2

Question 3