4.5 Physical Properties of Covalent Molecules. Summary of Bonding Types. Small Covalent Molecules (polar & non-polar) e.g. H 2 O, I 2 , CO 2 , NH 3 , HF, CH 4 , C 2 H 5 OH. Hydrogen bond between molecules. Water H 2 O Polar. Covalent bonds within molecule.
Physical Properties of Covalent Molecules
Hydrogen bond between molecules
Covalent bonds within molecule
Strong covalent bonds between the hydrogen and oxygen atoms (intramolecular) and hydrogen bonds between molecules (intermolecular forces).
Weak intermolecular van der waals forces between individual molecules
Covalent bonds / shared electrons between iodine atoms in the molecule
Amino acids are the repeating units of protein molecules
Physical properties are governed by the intermolecular
a)van der Waals (non-polar covalent molecules)
b)permanent dipole-permanent dipole (the strongest IMF found in polar covalent molecules)
c)hydrogen bonds (found in polar covalent molecules with O-H, F-H and N-H bonds)
All molecules contain van der waals forces
Lining up for fresh water after the city of Harbin’s water supply, the Songhua river was contaminated by a chemical explosion in a benzene (C6H6) factory. Being a very stable, unreactive non-polar molecule, its insolubility in water posed challenges for those involved in cleaning up the spill.
Melting Point and Boiling Point
Mpt KF = 1500°C (ionic) Mpt (F2) = - 220°C (non-polar)
Mpt K = 760 ° C (metallic) Mpt (HF) = - 83 °C (polar)
NH3(l) + H2O (l) ↔ NH4+(aq) + OH- (aq)