Lecture 5 The Water Molecule - Water Life Civilization Why...

1
Water, Life, Civilization: Why Water?
Water: H
2
O
Water: H
2
O

2
H
H
H
H
O
S
Water
Hydrogen Sulfide
Water and Similar Compounds
H
2
S
H
2
O
Hydrogen Sulfide: H
2
S Water: H
2
O
Boiling Point and Freezing Point
F.P B.P liquid range
Water (H
2
O) 0
o
C 100
o
C 100
o
C
Hydrogen Sulfide (H
2
S) -84
o
C -60
o
C 24
o
C
Hydrogen Selenide (H
2
Se) -64
o
C -42
o
C 22
o
C
Hydrogen Telluride (H
2
Te) -49
o
C 2
o
C 47
o
C
Water is the only substance that exists as a gas, solid, and
liquid at ambient earth temperatures
Solid Gas

3
H
2
O
Two hydrogen atoms
One Oxygen atom
What makes water so unusual?
Hydrogen: 1 electron (-), 1 proton (+)
Oxygen: 8 electrons (-), 8 protons (+)
In water, the hydrogens shares their one
electron with oxygen, which shares
one of its electrons with each hydrogen.
This sharing of electrons forms the
bond between hydrogen and oxygen
atoms to make the water molecule.
Nucleus
1 Proton (+)
1 Electron (-)
Hydrogen
H