7.2.1-2 - Structure, Formulae & Reactions of Alkenes

Describe the combustion of alkenes.

They burn with smoky flames due to incomplete combustion.

Describe addition reactions of alkenes.

Addition atoms across the C=C double bond so that the double bond becomes a single C-C bond.

• With hydrogen - hydrogenation; requires a higher temperature and a nickel catalyst.

• With steam - hydration; requires high temperature, pressure, and concentrated phosphoric acid (HPO) as a catalyst.

• With Br₂ / Cl₂ / I₂ - addition of halogens

State characteristics of methanol, ethanol, propanol, and butanol.

• Dissolve in water to form a neutral solution.

• React with sodium to form hydrogen.

• Burn in oxygen.

• React with carboxylic acids in presence of acid catalyst to form esters.

What are the formulas for ethene, propene, butene, and pentene?

• Ethene: C₂H₄

• Propene: C₃H₆

• Butene: C₄H₈

• Pentene: C₅H₁₀