Page 22 - Ranger SPM 2022 Chemistry

Chemistry SPM Chapter 2 Carbon Compound
Alkane Alkene
1. Alkanes are saturated hydrocarbons 1. Alkenes are more reactive
with carbon-carbon single bond that hydrocarbons compared to alkanes
is very stable. because they have at least one
2Rights Reserved.
carbon-carbon double bond.
2. A large amount of heat is needed 2. Alkenes undergo combustion in
to break the stable single covalent oxygen. The combustion produces
bond. sooty yellow flame:
(a) Alkenes undergo complete
3. Alkanes are the least reactive combustion in excess oxygen
organic compounds because they do to produce carbon dioxide and
not react with most of the chemical water.
substances. C H (g) + 3O (g) →
2
4
2
4. Alkanes undergo combustion in 2CO (g) + 2H O(l)
2
2
oxygen. The combustion produces (b) Alkenes undergo incomplete
sooty yellow flame: combustion to produce carbon
(a) Alkanes undergo complete monoxide or carbon and water.
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combustion in excess oxygen • C H (g) + 2O (g) →
to produce carbon dioxide and 4 2 2CO(g) + 2H O(l)
water. 2
CH (g) + 2O (g) → CO (g) + • C H (g) + O (g) →
2
4
2
4
2
2
2H O(l) 2C(s) + 2H O(l)
2
2
(b) Alkanes undergo incomplete 3. Alkenes undergo six different
combustion to produce carbon addition reactions to convert carbon-
monoxide or carbon and water. carbon double bond to carbon-carbon
• CH (g) + 3 O (g) → single bond.
(a) Hydrogenation
2
4
2
CO(g) + 2H O(l) • Ethene gas reacts with
2
• CH (g) + O (g) → hydrogen gas in specific
conditions to produce ethane.
4
2
C(s) + 2H O(l) • Specific conditions needed:
2
o
5. In the presence of ultraviolet (UV) (i) Temperature: 180 C
rays, alkanes undergo substitution (ii) Catalyst: nickel or
reaction with halogen: platinum powder Form 5
Catalyst
• CH (g) + Cl (g) UV • C H (g) + H (g) ⎯⎯→ C H (g)
2
2
6
180 °C
2
4
4
2
CH Cl(g) + HCl(g)
3
H H H H
• CH Cl(g) + Cl (g) UV Catalyst
2
3
CH Cl (g) + HCl(g) H C C H + H H 180 °C H C C H
2
2
• CH Cl (g) + Cl (g) UV H H
2 2 2
CHCl (g) + HCl(g) • Used to convert vegetable
3
oil (unsaturated fat) into
• CHCl (g) + Cl (g) UV margarine (saturated fat).
3
2
CCl (g) + HCl(g)
4
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02.5 RANGER SPM CHEMISTRY 2P.indd 151 29/03/2022 2:28 PM