OChem - Intermolecular Forces

krabi's version from 2015-06-08 11:29

Section 1

Question Answer
What is a dipole moment? Occurs when the centre of + charge does not coincide with the -ve charge centre They are not on the same page
What is Measured in U=qd ?When having a dipole moment, he goes “polar” Measured in Debye - Is product of the amount of charge (q) x distance between centre of charge (d) Due to differences in electroneg
What molecule has the biggest dipole moment? Why?The larger the difference in electronegativities of bonded atoms, the larger the dipole moment. For example, NaCl has the highest dipole moment because it has an ionic bond (i.e. highest charge separation).
Are all polar bonds having dipole moment? NO, may or may not have DM
How can I get a Dipole Moment? It can be induced by a electric field, NP bond/molecule or ion
What is the difference between IDF and intermolecular attraction (IA)IA is when a partial positive is attracted to a positive negative. IDF is a temporary passing bond. They are short lived and weaker than (induced dipoles, than covalent bonds. ) IDF can happen in a non polar molecule.
What is Bond Energy? The Average energy to break a bond.
What is electrostatic force? Between electrons and protons holding it together Inter/intramolecular forces are electrostatic.
Why is low energy good? Means a stable system.

Section 2

Question Answer
What is an Isomer? Different compounds (unique) w/same molecular formula.
Conformational Isomer? Different spatial orientation of the SAME molecule -- Not a true isomer
How is Configuration different from Conformation?hfjdkashfd
Structural isomer? Same molecular formula w/diff Bond 2 Bond connections
Stereoisomer?2 unique compounds have the same formula and bond connections Have at least one chiral centre Two kinds: diasters and enantiomers For example, a Sony walkman and GE walkman - differ as unique brand, but same technology, have at least 1 logo on walkman
Enantiomers? Not same molecule -- BUT have non-superimposable mirror images, same connectivity, same formula (w/1 chiral location). Rotate light in opposite directions and to equal degree
Racemic mixture?When enantiomer is mixed in 50/50 ⇒ cancel each other out so does not rotate light
When can enantiomers rotate light? When mixed in unequal concentrations - to the degree by the excess concentration
Do enantiomers have the same chemical and physical characteristics? YES, except in two cases: rx w/other chiral compounds rx w/plan polarized light

Section 3

Question Answer
What is the resolution of enantiomers? When it is separated.