Presentation on theme: "Presented by Leticia Bonita Prince Newcastle University 4 th Year MChem Student."— Presentation transcript:
Presented by Leticia Bonita Prince Newcastle University 4 th Year MChem Student
Aims of Today Increase your understanding of intermolecular interactions Increase your spatial skills and awareness using software designed by the CCDC
What are Spatial Skills? The ability to mentally manipulate 2-dimensional and 3- dimensional figures. Important in chemistry, biology, medicine, mathematics, physics and everyday life.
Introduction Non-covalent interactions between functional groups in different molecules: Hydrogen Bonding – The attraction between a hydrogen on one molecule and an electronegative element on another Van der Waals’– Temporary or permanent dipole-dipole interactions
Boiling Points The stronger intermolecular forces, the higher the boiling point: HCl > HBr > HI Relative Boiling Points: AMIDE > CARBOXYLIC ACID > NITRILE >> ACYL CHLORIDE ~ ALDEHYDE ~ KETONE
Hydrogen Bonding Requirements for a Hydrogen Bond: An H atom covalently bonded to another electronegative atom (e.g. O, Cl, N, etc.) i.e a polar bond where the H has a partial positive charge. A second electronegative atom* on a nearby which can easily access the H atom, and thus can donate electron density to it.
Solubility Molecules that can form hydrogen bonds are generally soluble in other molecules that can form hydrogen bonds. Ethanol is completely miscible in water as the –OH group can be involved in H bonding with water. Propane is INSOLUBLE in water because it’s not polar, nor capable of forming H bonds.