BRAINCAKEReactions and Reactive Species
Revision notes for Reactions and Reactive Species 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.
- Free radicalsUltraviolet light can break covalent bonds.
- NucleophilesAn atom of group of atoms that can donate a pair of electrons to form a dative covalent bond.
- ElectrophilesElectrophiles are electron deficient atoms or groups of atoms.
- AcidsAn acid is a proton donor.
- BasesA base is a proton acceptor.
- Oxidising AgentsOxidation is any one or more of loss of electrons increase in oxidation number gain of oxygen loss of hydrogen Acidified potassium dichromate (VI)…
- Reducing AgentsReduction is one or more of gain of an electron decrease in oxidation state loss of oxygen gain of hydrogen LiAlH4 in dry ether, NaBH4…
- SubstitutionSubstitution reactions occur when one functional group is replaced by another or a hydrogen atom is replaced by a functional group.
- AdditionAddition reactions occur when a π bond (double bond) is broken and an atom or group of atoms is added to the saturated compound.
- EliminationElimination reactions occur when atoms are removed from the molecule.
- Addition-EliminationIn addition-elimination reactions a group is first added, then another group is removed.
- Acid-Base ReactionsAcid-base reactions take place when one molecule acts as an acid and accepts a proton and the other molecule acts as a base and donates a proton.
- OxidationOxidation reactions occur when hydrogen atoms are removed or when oxygen atoms are added to organic molecules.
- ReductionReduction is the addition of hydrogen or the removal of oxygen.
- CombustionCombustion is the reaction with oxygen.
- CrackingCracking converts longer-chain hydrocarbons into shorter-chain hydrocarbons.
- ReformingAlkanes with straight chains burn less efficiently than branched and cyclic alkanes (rings).
- CondensationA condensation reaction joins two molecules by the removal of a small molecule which is usually a water molecule.
- HydrolysisHydrolysis is the breaking of a covalent bond by the addition of a molecule of water.
- PolymerisationA polymer is a long molecule made up of lots of small repeating molecules called monomers joined together.