Physical Chemical Properties of Water
I Abundance and distribution of water
A.
The presence of large amounts of liquid water makes Earth unique
B. Most Water on the planet originated from the lithosphere
"juvenile water"
C. Amounts of water in various sinks (all x 1020 g)
1. Primary Lithosphere
250,000
2. Oceans
13,800
3. Sedimentary Rocks
2,100
4. Polar & other Ice
167
5. Circulating Ground water
2.5
6. Inland Waters
0.25
7. Atmosphere
0.13
II Physical - Chemical uniqueness of water
A. Melting and boiling points of similar dihydrides
H20 H2S H2Se H2Te
M.P.oC 0.0 -82.9 -64 -48
B.P.oC 100 -59.6 -42 -2
B. Melting and Boiling points of similar "oxidants"
H4C H3N H2O HF
M.P.oC -182.6 -77.7 0.0 -83
B.P.oC -161.4 -33.4 +100 +19.7
C. Additional properties of water
1. High specific heat
2. High surface tension
3. High viscosity
4. High dielectric constant
III Nature of the structure of water
A.
Water both as ice and liquid has a significant fraction of the H20 molecules held
by hydrogen bonds.
1.
2.
B.
The thermal inertia of water is due to the energy expended in breaking these bonds
The low density of ice is due to the expanded crystal structure imposed by these
bonds
The polarity and high dielectric constant of water mean that it can dissolve a wide
range of materials
1.
2.
3.
4.
Ionic compounds can be ionized
Non-ionic polar compounds can be dissolved by forming hydrogen bonds with
water
Water can form sols with very large polar substances
Water can form micelles with very large materials possessing hydrophilic groups