formulas and isomerism definitions Flashcards
what is empirical formula?
simplest whole number of ratio of the atoms of each elements in a molecule
what is molecular formula?
actual number of atoms of each element in molecule
what is general formula?
algebraic formula that describes any member of a homologous series
what is a homologous series?
family of organic molecules that have same general formula and functional group
- differ by -CH2
- different physical properties
what is structural formula?
shows arrangement of atoms in molecule in simplified form
what is displayed formula?
shows every atom and bond in molecule
what is skeletal formula?
shows bonds of carbon skeleton only
what are the two types of isomers?
- structural isomers
- stereoisomers
what is a structural isomer?
molecule with same molecular formula but different structural formula
what are the three types of structural isomers?
- chain
- position
- functional group
what are chain isomers and their properties?
- different arrangement of carbon skeleton
- similar chemical properties
- different physical properties
what are position isomers and their properties?
- different position of functional group
- same carbon skeleton
- similar chemical properties
- different physical properties
what are functional group isomers and their properties
- different functional group
- different chemical properties
- different physical properties
state three types of functional group isomers
- aldehydes/ketones
- acids/esters
- alchols/ethers
what is a geometric isomer?
same molecular formula but different spatial arrangement
what is the other type of stereoisomer?
optical isomerisms
what rules are used for stating E-Z isomerism?
Cahn-Ingold-Prelog priority rules (CIP)
how does CIP rules work?
- look at atoms attached directly to carbon on either side of double bond
- the atom with highest atomic number has higher priority
- if the both atoms attached to carbon atom on same side of double bond are the same, look at next atom in group
- if the highest priority groups are both above/below - Z isomerism
- if they are different then its E isomerism
why do alkenes exhibit E-Z isomerism?
restricted rotation due to double covalen bonds so gropus on either side of bond are frozen
since structures cannot interchange easily, the atoms occupy differnt spatial arrangements
