Definitions Flashcards
Define empirical formula
Simplest whole no ratio of atoms of elements in a compound
What is the molecular formula
The actual number of atom of each element in a compound
Define homologous series
Same functional group and general formula
Define aromatic compounds
Contain benzene ring
Define aliphatic compounds
Straight chains
No benzene ring
What is alicyclic
Non aromatic rings
Define isomer
Same molecular formula
Atoms arranged differently
What are chain isomers
Carbon skeleton arranged differently
What are positional isomers
Functional group is attached to a different carbon atom
What is a functional group isomer
Atoms arrange into different functional groups
What is heterolytic fission
Bond splits unevenly
1 atom receives both electrons
Forming a positive ion (cation) and a negative ion (anion)
What is homolytic fission
Bond splits evenly
Both atoms receive 1 electron
Forms 2 free radicals
What is a free radical
Particles with an unpaired electron
What is sigma bond
2 s orbitals overlap in a straight line
Giving high electron density between the 2 bonded nuclei
So there is a string electrostatic attraction between the nuclei and shared electrons
High bond enthalpy
Strong bond
Single bond
What is a pi bond
Double covalent bond
2 p orbitals overlap sideways -one below and one above the nuclei
Weak = electron density spread out across bond = low bond enthalpy
What is An électrophile
Electron pair acceptor
What is a nucleophile
Electron pair donor
What is stereoisomers
The same structural formula
Different arrangement in space
What is a carbocations.
Organic ion containing a positive C
What is markownikoffs rule
The major product on the addition of a hydrogen halide to an unsymmetrical molecule is where the H is added to the C with the most H already
What is the Kekule model
Alternating single and double bonds on a 6C ring. With the molecule constantly flipping between isomers
What is the benzene ring
P orbitals of all 6 carbon atoms overlap to create a pi system
Makes 2 clouds of delocalised electrons - 1 above and 1 below the planar c ring
All bonds are the same lengths (between single and double)
What is a halogen carrier
Accepts a lone pair of electrons from a halogen atom on an electrophile
Polarising the electrophile
Making the electrophile stronger
What is phenol
One of the lone pairs in the oxygen atom overlaps with delocalised electron ring in the benzene ring
The oxygen lone pair become partially delocalised into the pi system
Increasing the molecule electron density
What are electron donating groups
Have electrons in orbitals that overlap with the delocalised electron benzene ring
Increasing electron density specifically at 2!4!6
Eg. OH, NH2, EDG
What are electron withdrawing groups
No lone pairs overlap with the delocalised electron ring on Benzene
And the atoms are electronegative so pull electrons out of the ring
Reduce electron density specifically at 2,4,6
Eg. NO2
What is ester acid hydrolysis
Splits the ester into a carboxylic acid and alcohol
Reflux
Dilute acid
Reversible reaction
What is ester base hydrolysis
Splits ester info a carboxylate salt (-COONa) and alcohol
Reflux
Dilute alkali (naoh)
What is an amine
1 or more h in NH3 is replaced by an organic group
What is an alpha amino acid
Both groups are attached to the same carbon atom
What is a chiral centre
A carbon atom with 4 different groups attached to it
What is an optical isomer
Mirror images no matter which way they are turned
Can’t be superimposed
What does optically active mean
They rotate plane polarised light.
One optical isomer rotates it clockwise and the other anti-clockwise
What are polymers
Long chains of molecules made by monomers
What is addition polymeratisation
Double bonds open
Molecules join
What is condensation polymerisation
Made of 2 types of monomers
The functional group of 1 monomer reacts with the other monomer fg
Each time a small molecule is lost (water)
