Isomers Flashcards
What are structural isomers
structures that share the same molecular formula and molecular weight but have different chemical and physical properties
What is the definition of physical properties
characteristics of PROCESSES that do not change the composition of matter
What is the definition of chemical properties
have to do with the reactivity of a molecule with other molecules that result in changes of the chemical composition
give examples of physical properties
melting point boiling point solubulity odor color density
Chemical properties are usually determined by _____ _____.
functional groups
How do STEREOISOMERS differ?
the arrangement of the atoms in space (wedge, dash)
How are STEREOISOMERS similar?
they share the same molecular formula and molecular connectivity
______ share the same molecular connectivity
Stereoisomers
What are the the two types of stereoisomers?
- configurational
- conformational
how do CONFORMATIONAL isomers differ
in rotation around a single sigma bond
_______ isomers differ in rotation around a single sigma bond
conformational
______ isomers can be interconverted by breaking bonds only
configurational
Conformational isomers have the same:
connectivity, molecular formula
What is angle strain in cyclic conformation
when bond angles are deviated from their ideal values by being stretched or compressed
What is torsional strain
when cyclic molecules assume conformations the hav e eclipsed or gauche interactions
What is non bonded strain
when atoms or groups compete for the same space
What is the most stable conformation of cyclohexane>
chair
During a chair flip______ components become _____
axial, equatorial
Components pointing up from the plane are (wedge/dash)
wedge
Components pointing down from the plane are (wedge/dash)
dash
if two groups are on the same side of the plane of a ring they are considered
cis
if two groups are on oppoiste sides of a plane of a ring they are considered
trans
What are the two categories of configurational isomers
enantiomers
diastereomers
if a molecule is chiral it lacks
internal plane of symmetry
_____ objects have mirror images that CAN be superimposed
achiral
Molecules that are nonsuperimposible (chiral) are:
A. Diastereomeres
B. Enantiomers
B
_______ are chiral and share the same connectivity but are NOT mirror images of each other
enantiomers
A carbon with only 3 different substituents are
achiral
An optically active compound can
rotate lig
An optically active compound can
rotate plane polarized light
for any molecule with n chiral centers there are ___ possible stereoisomers
2^n
____ are non-mirror image configurational isomers
diastereomers
if two substituents are on the same side of an immovable bond are
cis
if two substituents are on opposite sides of an immovable bond are
trans
what must be for a compound to be optically active (2 things)
have chiral centers, lack plane of symmetry
A compound with chiral centers and an internal plane of symmetry
meso compound
