3.1- nomenclature and isomerism Flashcards
properties of homologous series (4)
-same general formula
-same functional group
-similar chemical properties
-each consecutive member differs by CH2
what is an empirical formula
simplest whole number ratio of atoms of elements in a compound
what is a molecular formula
actual number of atoms of elements in a compound
what is a structural formula
shows arrangement of atoms, but not bonds
eg. CH3-CH2-CH2-CH3
what is a displayed formula
shows every atom and every bond in a compound
what is a skeletal formula
only shows bonds, not atoms
general formula for halogenoalkanes
CnH2n+1 X
what are isomers
molecules with same formula but different arrangement of atoms
what are structural isomers
same molecular formula, different structural formula
- position isomers
-chain isomers
-functional group isomers
what are chain isomers
same molecular formula, but carbon skeleton is arranged differently
eg. pentane, methylbutane and dimethylpropane
which isomer out of pentane, methylbutane and dimethylpropane has the lowest BP
-dimethylpropane, as it has the most branched chains
-VDW forces are weaker in small molecules
what are position isomers
same molecular formula and carbon skeleton, but different functional group position
eg. 1-bromopropane and 2-bromopropane
what are functional group isomers (2)
same molecular formula, but different functional groups
-they have different chemical and physical properties
eg.hex-3-ene and cyclohexane
why do branched molecules have lower BPs (3)
-branching makes molecule more spherical
-reduces contact surface area between molecules
-weaker VDW forces between molecules
what are stereoisomers
they have a different spatial arrangement
