AS Level Chemistry - Unit 14.2 Alkenes

**This Powerpoint specifically uses the Cambridge AS Level Chemistry Syllabus (9701) and covers all criteria for – Unit 14.2 Alkenes
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Students will be able to -

1 recall the reactions (including reagents and conditions) by which alkenes can be produced:
(a) elimination of HX from a halogenoalkane by ethanolic NaOH and heat
(b) dehydration of an alcohol, by using a heated catalyst (e.g. Al 2O3) or a concentrated acid
(e.g. concentrated H2SO4)
© cracking of a longer chain alkane

2 describe the following reactions of alkenes:
(a) the electrophilic addition of
(i) hydrogen in a hydrogenation reaction, H2(g) and Pt/Ni catalyst and heat
(ii) steam, H2O(g) and H3PO4 catalyst
(iii) a hydrogen halide, HX(g), at room temperature
(iv) a halogen, X2
(b) the oxidation by cold dilute acidified KMnO4 to form the diol
© the oxidation by hot concentrated acidified KMnO4 leading to the rupture of the carbon–carbon
double bond and the identities of the subsequent products to determine the position of alkene
linkages in larger molecules
(d) addition polymerisation exemplified by the reactions of ethene and propene

3 describe the use of aqueous bromine to show the presence of a C=C bond

4 describe the mechanism of electrophilic addition in alkenes, using bromine/ethene and hydrogen bromide/propene as examples

5 describe and explain the inductive effects of alkyl groups on the stability of primary, secondary and tertiary cations formed during electrophilic addition (this should be used to explain Markovnikov addition)

**Every Powerpoint includes learning objectives, a starter and plenary, suitable activities and review questions with mark scheme. We also provide a free pdf version of the file so it can easily be printed for students as a handout or uploaded to the school VLE system
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