water by ved
TRANSCRIPT
Water
Properties of water
Outline
Properties of Water
Properties of Water
High b.p., m.p., heat of vaporization, surface tension
Bent structure makes it polar Non-tetrahedral bond angles H-bond donor and acceptor Potential to form four H-bonds per water
Comparison of Ice and Water
Issues: H-bonds and Motion Ice: 4 H-bonds per water molecule Water: 2.3 H-bonds per water molecule Ice: H-bond lifetime - about 10 microsec Water: H-bond lifetime - about 10 psec
Solvent Properties of Water
Ions are always hydrated in water and carry around a "hydration shell"
Water forms H-bonds with polar solutes Hydrophobic interactions - a "secret of life"
Hydrophobic Interactions
A nonpolar solute "organizes" water The H-bond network of water reorganizes
to accommodate the nonpolar solute This is an increase in "order" of water This is a decrease in ENTROPY
Amphiphilic Molecules
Also called "amphipathic" Refers to molecules that contain both
polar and nonpolar groups Equivalently - to molecules that are
attracted to both polar and nonpolar environments
Good examples - fatty acids