BRAINCAKEAlkenes
Revision notes for Alkenes in OCR Chemistry A (H432). Read the start of any lesson here, then sign in free for the whole lesson, the R.E.C.I.P.E. recall steps and the quiz.
- AlkenesAlkenes have the general formula CnH2n.
- Bonding in AlkenesThe C=C double bond consists of one σ and one π bond.
- Stereoisomerism in AlkenesStereoisomers have the same structural formula but different arrangements of the atoms in space.
- Reactions of AlkenesThe pi bond is weaker than the sigma bond so is broken more readily.
- HydrogenationWhen an alkene such as propene is mixed with hydrogen gas and passed over a nickel catalyst at 423K, an alkene such as propane is formed.
- Reaction with HalogensAlkenes react readily with halogens at room temperature and in the dark.
- Reaction with Hydrogen HalidesAlkenes react with gaseous hydrogen halides or hydrogen halides in solution (acids) at room temperature.
- Reaction with SteamThis reaction is also known as hydration.
- Oxidation of Alkenes to DiolsA diol is a compound containing two hydroxyl -OH groups.
- Addition PolymerisationCompounds containing the C=C double bond can be polymerised.
- Environmental ConcernsThe lack of reactivity makes polymers useful for storage and packaging, but many polymers are non-biodegradable.