AS Organic Chemistry Key Terms and Processes Flashcards
Why does carbon form a large number of compounds?
- Each carbon atom can form four covalent bonds to other atoms
- They can be either single, double or triple bonds
- Carbon atoms can also bond to other carbon atoms forming long carbon chains
Define the term ‘hydrocarbon’
A hydrocarbon is a compound containing hydrogen and carbon atoms only
Define the term ‘saturated hydroacrbon’
A saturated hydrocarbon has single bonds only
Define the term ‘unsaturated hydrocarbon’
An unsaturated hydrocarbon contains carbon to carbon multiple bonds
Define the term ‘Homologous series’
A family of hydrocarbons with similar chemical properties who share the same general formula and have the same functional group and each successive member differs by CH2
Define the term ‘functional group’
The part of the organic compound that is largely responsible for the molecule’s chemical properties
Define the term ‘aliphatic’
Carbon atoms are joined in un-branched or branched chains, or non-aromatic rings
Define the term ‘alicyclic’
Carbon atoms are joined to each other in ring structures, with or without branches
Define the term ‘aromatic’
Some or all the Carbon atoms are found in a benzene ring
Define the term ‘alkanes’
Containing C-C bonds
Define the term ‘alkenes’
Containing C=C bonds
Define the term ‘alkynes’
Containing at least one triple C to C bond
Define the term ‘empirical formula’
Simplest whole number ratio of the atoms of each element present in a compound
Define the term ‘molecular formula’
The number and type of atoms of each element present in a molecule
Define the term ‘general formula’
the simplest algebraic formula for any member of a homologous series
Define the term ‘displayed formula’
Shows the relative positioning of all the atoms in a molecule and the bonds between them
Define the term ‘structural formula’
Uses the smallest amount of detail necessary to show the arrangement pf atoms in a molecule
Define the term ‘skeletal formula’
a simplified organic formula that removes:
- all the the carbon and hydrogen labels from carbon chains
- any bonds to hydrogen
And leaves just a carbon skeleton and any functional groups
Define the term ‘structural isomerism’
Compounds with the same molecular formula nut different structural formulae
Covalent bond
A shared pair of electrons between two atoms
Homolytic Bond Fission
When a covalent bond is broken, each of the bonded atoms takes one of the shared pair of electrons from the bond, each atom has a single unpaired electron called a radical
Heterolytic Bond Fission
When a covalent bond beaks, one of the bonded atoms takes both bonded electrons; the atom that tales both electrons becomes an anion, and the other becomes a cation
What do ‘curly arrows’ in reaction mechanisms represent?
Used to show the movement of electron pairs when bonds are broken/made
Bonding in alkanes
- Each carbon atom is joined to four other atoms by single covalent bonds, sigma bonds, as a result of the direct overlap of two orbitals
Shape of alkanes
Each C12 atom is surrounded by four e- pairs in four σ bonds, electron pair repulsion results in a tetrahedral structure, with a bond angle of 109.5 degrees
Physical Properties of alkanes
- Alkanes have low melting or boiling points because of the very weak intermolecular forces between alkane molecules
- MP and BP increase with increasing chain length as there are more electrons in molecules, so more London forces
- insoluble in water, non-polar molecules, no points of attack for polar molecules
Chemical properties of alkanes
- generally unreactive, harsh conditions needed to bring about a reaction
Physical properties of alkenes
- MP and BP increase with increasing chain length and molecular weight
- MP and BP lower that respective alkanes, as they cannot pack together as well as alkanes, so less id:id forces are established, hence less energy is required
- insoluble in water
Stereoisomers
compounds with the same structural formula but different spatial arrangement
E/Z isomers
Restricted rotation about the C=C bond, and two different groups should be attached to each of the carbons in the double bond
Cis-trans isomers
a special case where two groups attached to each C atom of the C=C bond are the same
