Chapter 5 Flashcards
define a constitutional isomer
a constitutional isomer has the same molecular formula but different constitution
define a stereoisomer
a stereoisomer has the same molecular formula and constitution but different spatial arrangement of atoms
what characterizes a cis stereoisomer?
the identical groups are on the same side of a double bond
what characterizes a trans stereoisomer?
the identical groups are on opposite sides of a double bond
is it cis or trans if two groups are connected at the same spot?
neither.
define chirality center
a chirality center is a tetrahedral carbon with four different groups around it
define enantiometer
an enantiomer is a type of stereoisomer. it is the non-superimpose-able mirror image
S is clockwise or counterclockwise?
counterclockwise
R is clockwise or counterclockwise?
clockwise
how do enantiomers behave with plane-polarized light? melting or boiling?
a pair of enantiomers will have the same physical properties (melting and boiling points), but will rotate plane-polarized light in opposite directions
what is a racemic mixture?
a solution containing equal amounts of both enantiomers in a pair. (net rotation of plane polarized light will be zero.)
define a diastereomer
disastereomers are stereoisomers that are non-superimpose-able and NOT mirror images
how many stereoisomers is it possible for one molecule to have given that it has n chirality centers?
2^n. each chirality center has a enantiomer pair, which can add up to up to 2^n. however, some of the configurations may end up being redundant.
what is rotational symmetry?
for a ring, rotational symmetry is when a molecule looks the same when rotated 180 degrees around an axis of symmetry.
what is reflectional symmetry?
reflectional symmetry is when a molecule looks the same on either side of a plane of symmetry. (or around one point, which is known as inversion.)
