Arthur JP Martin
Richard LM Synge. These 2 developed the concept of Partition Chromatography
Jean Baptiste Perrin of Sorbonne for developing equilibrium sedimentation in colloidal solutions
Theodore Svedberg: analytical ultracentrifugation. Awarded based on his work in disperse systems
Arne Tiselius. This led to a muchimproved method of electrophoretic analysis which he refined in subsequent years.
Migration of protein mols in an electrical field
Marie Curie who developed methods for the separation of radium from radioactive residues in sufficient quantities to
allow for its characterization and the careful study of its properties, therapeutic properties in particular.
2. a. Benzene = It is nonpolar. With it being a symmetrical molecule all its dipole movements are canceled out by a
equal and possible dipole movement on the other side of the molecular. LONDON FORCES which are very weak,
instantaneous forces between the molecules of a substance, caused be the momentary unequal distribution of the
electron clouds around the nucleus. (the unequal distribution of the electron clouds occurs because the electrons are
constantly moving, so the probability of them all being at random points within their energy levels, rather than
perfectly symmetrical around the nucleus, is very high.) However, because benzene is a relatively large molecule, as
compared with smaller hydrocarbons, it will have a slight dipole moment. This occurs because as the size of a
molecule increases (even in this case where it is nonpolar) there is more surface area over which induced dipoles (a
form of the London Dispersion forces) can occur.
b. Chlorobenzene = POLAR. It has one polar CCl bond (with partial negative charge on the Cl and partial positive
charge on the C)
This delocalisation is by no means complete, but it does have a significant effect on the properties of both the carbon
chlorine bond and the polarity of the molecule.
The delocalisation introduces some extra bonding between the carbon and the chlorine, making the bond stronger.
This has a major effect on the reactions of compounds like chlorobenzene.
There is also some movement of electrons away from the chlorine towards the ring. Chlorine is quite electronegative
and usually draws electrons in the carbonchlorine bond towards itself. In this case, this is offset to some extent by the
movement of electrons back towards the ring in the delocalisation. The molecule is less polar than you would
otherwise have expected.
c. nBUTANE = nonpolar. London dispersion forces. • Alkanes are nonpolar molecules where the only
intermolecular force operating is the weakest possible, that is the instantaneous dipole induced dipole
intermolecular forces. These are sometimes called Londondispersion forces and occur between ALL
molecules, even single atoms of the noble gases. Van der Waals forces include all types of intermolecular forces
which are not due to an actual chemical bond BUT sometimes this name is used just to mean these instantaneous
dipole induced dipole dispersive forces (sorry but it can be confusing!).
The electronegativities are: C (2.5) and H (2.1) and produces a virtually nonpolar bond and any very small
effects will tend to cancel out e.g. HCH situations and so alkanes are the least polar organic molecules i.e.
as near nonpolar molecules you will get.
• These electrical attractive forces act between ANY atoms or molecules and is primarily a function of the number of
electrons in the molecule, though their spatial distribution can be significant.
• The larger the molecule, i.e. the greater the number of electrons in it, the more polarizable it is and so the
attractive force is greater.
• The force arises from the instantaneous and random asymmetry of the electron fields in the atomic
orbitals because of the random behaviour of electrons in the atomic or molecular orbitals.
• A transient δ+ in one molecule induces a transient δ in a neighbouring molecule, so causing a very weak
and transient electrical attraction.
d. Cyclohexane = nonpolar. It’s most likely due to the unsaturated double bond in cyclohexene. Cyclohexane, with no
unsaturations, is "flexible", and able to sit in the chair conformation you’ve seen in your classes. This chair
conformation is "stackable", e.g. the molecules are able to pack together fairly closely. This increases van der Waals
interactions. It is the stronger intermolecular forces that give cyclohexane its higher m.p. Conversely, the unsaturated
cyclohexene takes on a less "stackable" conformation due to decreased flexibility. This decreases the van der waals
interactions. In addition, the pi electron clouds of the double bonds repel each other fairly strongly, also decreasing
4. Anomer = A cyclic stereoisomer, such as a sugar, whose sole conformational difference involves the arrangement
of atoms or groups in the aldehyde or ketone group.
one of two stereoisomers (designated α or β) of the furanose or pyranose form of a sugar, e.g. αdglucose. αforms
have −OH group of the anomeric carbon below the plane of the furanose or pyranose ring.
Epimer = Epimers are monosaccharides that differ in chirality at only one carbon. In the straightchain format,
epimers will have H and OHsubstituents switched at one backbone carbon, but not at any others.
Anomers are special epimers; in cyclic forms of one single monosaccharide, anomers differ in chirality at the
anomeric (hemiacetal) carbon only. In the straightchain format, anomers will have the same configuation.