Liquids & Solids. Chapter 13. Heat of Fusion/Vaporization. H 2 O (s) ----> H 2 O (l) H fusion = 6.02 kj/mol H 2 O (l) ----> H 2 O (g) H vaporization = 40.6 kj/mol From the H o values above, which two states are most similar?
Viscosity: Resistance to flow (molecules with
large intermolecular forces).
Higher altitude--lower b.p.
Top of Mt. Everest--70 oC
Q = (ms t)ice + m Hf + (ms t) water + m Hv + (mst)steam
Q = KE & PE + PE + KE & PE + PE + PE & KE
within the molecule
London Dispersion ForcesTypes of Bonding
When ice changes to liquid and then to vapor, the
intramolecular forces (covalent bonds) stay intact, only
the weaker hydrogen bonds between molecules weaken
and break. These are, therefore, physical changes.
among water molecules.
elements in Groups 4A, 5A, 6A, & 7A. The high
boiling points of HOH, NH3, HF is due to hydrogen
between nonpolar molecules -- London
Dispersion Forces. LDF forces are both weak
a liquid with a given energy versus kinetic energy
at two different temperatures.
solid, and c) molecular solid.
the nature of the forces that hold the solid together.
Substances that have a mixture of elements and metallic properties.