13. Intro to AS Level Organic Chem Flashcards
What is a hydrocarbon?
A compound made up of carbon and hydrogen only.
What are alkanes?
Simple, saturated hydrocarbons with no functional group.
General formula CnH2n+2
What is a functional group?
A group of atoms which dictates a compound’s physical and chemical properties.
What is a saturated compound?
Contains the max amount of hydrogen atoms possible (single bonds only).
What is an unsaturated compound?
Contains a carbon-carbon double or triple bond.
What is homolytic fission?
The splitting of a covalent bond where each atoms retains one electron from the bonding pair.
What is heterolytic fission?
The splitting of a covalent bond where one atom retains both electrons from the bonding pair.
What is a free radical?
An uncharged molecule with an unpaired electron.
What is initiation?
An initial chemical reaction which triggers further reactions.
What is propagation?
A secondary reaction where there is no net gain or loss of free radicals.
What is termination?
The final step in a chain reaction where a reactive intermediate is rendered inactive.
What is a nucleophile?
A molecule or substance that donates electrons.
What is an electrophile?
A molecule or substance that acts as an electron pair acceptor.
What is an addition reaction?
A reaction where two or more molecules react to form a larger molecule.
What is a substitution reaction?
A reaction where an atom or group is replaced by another atom or group.
What is an elimination reaction?
A reaction in which two substituents are removed from a molecule in a mechanism with one or two steps.
What is hydrolysis?
The splitting up of a compound or molecule using water.
What is a condensation reaction?
The formation of a compound with the release of water.
What is oxidation?
The loss of electrons.
What is reduction?
The gain of electrons.
What are the 3 main shapes of organic molecules?
Straight-chained, branched and cyclic.
How are molecules with hybridised sp orbitals shaped?
One s orbital and one p orbital hybridise to form 2 sp orbitals
They repel to give a liner shape with a 180° bond angle
How are molecules with hybridised sp2 orbitals shaped?
One s orbital and two p orbitals hybridise to form 3 equivalent sp2 orbitals
They all repel each other to give a trigonal planar arrangement with a bond angle of 120°
The unchanged 2p orbital lies perpendicular
eg ethene
How are molecules with hybridised sp3 orbitals shaped?
One s orbital and three p orbitals hybridise to form 4 equivalent sp3 orbitals
They all repel each other to give a tetrahedral arrangement with a bond angle of 109.5°
eg ethene
What are structural isomers?
Molecules with the same molecular formula but a different structure formula.
What are the different types of structural isomerism?
Chain isomerism: branching on the carbon chain
Functional group isomerism: functional group changes
Positional isomerism: the groups attached to the carbon chain move around
What are stereoisomers?
Molecules with the same molecular and structural formula but a different arrangement of atoms in space.
Geometrical (cis-trans) or optical isomers
How does geometrical isomerism arise?
Pi bond causes restricted rotation around C=C double bond. meaning groups are fixed in position, causing different isomers to arise.
Cis: both of the highest priority groups on same end (above or below)
Trans: highest priority groups diagonally across from each other
What are optical isomers (enantiomers)?
Molecules with the same molecular and structural formulas but they are mirror images of each other, occurs where there is a chiral centre
What is a chiral centre?
A carbon atom bonded to 4 different groups
