10/5/2010
Unique Properties of Fresh Water
Seawater Chemistry
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Chapter 5: Unique properties of fresh water
Origin of Seawater???
Chapter 6: The 6 major constituents, trace elements
Salinity, normal, hypersaline, brackish
Changes in surface salinity
Sources of salts…….. Compare to river water
How salts removed?
The Principle of Constant Proportions
Conservative and Nonconservative Constituents
Residence Time
Determining Salinity
Desalination
CHAPTER 5
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H 2O
IMPORTANCE / PERCENTAGES (Hydro Cycle)/ AVAILABILITY
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UNIQUE PROPERTIES: See Table on Page 126
Only substance that occurs naturally in all 3 states within temp
range at earth’s surface.
Polar compound, hydrogen bonds
Ability to change its state (solid, liquid gas)
Maximum Density is at 4 degrees Celsius, thermal expansion and
contraction, lakes freeze from top down, not bottom up
Water has High Heat Capacity, changes temp slowly, latent heat
of vaporization and fusion, moderates earth’s climate, excellent
coolant
Water is less dense in the solid state
Adhesion, Cohesion & Surface Tension Surface Tension
(droplets, bubbles, capillary waves) and Viscosity
Dissolving ability (universal solvent)
Incompressibility
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10/5/2010
Figure 4.1
Molecule: the smallest particle of a substance that retains the chemical and
physical properties of the substance and is composed of two or more atoms
held together by chemical bonds.
Unique Properties of Fresh Water
CHAPTER 5
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Table 5.4
H 2O
IMPORTANCE / PERCENTAGES (Hydro Cycle)/ AVAILABILITY
• UNIQUE PROPERTIES: See Table on Page 126
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Only substance that occurs naturally in all 3 states within temp
range at earth’s surface.
Polar compound, hydrogen bonds
Ability to change its state (solid, liquid gas)
Maximum Density is at 4 degrees Celsius, thermal expansion and
contraction, lakes freeze from top down, not bottom up
Water has High Heat Capacity, changes temp slowly, latent heat of
vaporization and fusion, moderates earth’s climate, excellent
coolant
Water is less dense in the solid state
Adhesion, Cohesion & Surface Tension Surface Tension (droplets,
bubbles, capillary waves) and Viscosity
Dissolving ability (universal solvent)
Incompressibility
Specific Heat: the quantity of heat required to produce a unit
change of temperature in a unit mass of that material,
typically 1 gram of that material.
Heat Capacity: depends on the specific heat and the mass, ie
HC of 1Kg of water is 1,000 calories/C and HC of 1 Kg of shale
is 390 calories/C
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10/5/2010
Figure 6.24
Wood has high heat capacity
Latent heat of Vaporization: the amount of heat required to change the state
of 1 gram of water from liquid to gas without changing temperature. The latent
heat of evaporation is 585 cal/gram at 20 degree C.
Unique Properties of Fresh Water
CHAPTER 5
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Latent heat of Fusion (melting): the amount of heat required to change the
state of 1 gram of water from ice to liquid without changing temperature.
“Latent” means hidden or stored.
Fig. 5.8
H 2O
IMPORTANCE / PERCENTAGES (Hydro Cycle)/ AVAILABILITY
• UNIQUE PROPERTIES: See Table on Page 126
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Only substance that occurs naturally in all 3 states within temp
range at earth’s surface.
Polar compound, hydrogen bonds
Ability to change its state (solid, liquid gas)
Maximum Density is at 4 degrees Celsius, thermal expansion and
contraction, lakes freeze from top down, not bottom up
Water has High Heat Capacity, changes temp slowly, latent heat of
vaporization and fusion, moderates earth’s climate, excellent
coolant
Water is less dense in the solid state
Adhesion, Cohesion & Surface Tension (droplets, bubbles, capillary
waves) and Viscosity
Dissolving ability (universal solvent)
Incompressibility
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10/5/2010
Attenuation: the decrease in the intensity of light over
distance.
Rate of light attenuation also depends on the wavelength
Table 05_01
Table 05_01
Seawater Chemistry
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Chapter 5: Unique properties of fresh water
Origin of Seawater???
Chapter 6: The 6 major constituents, trace elements
Salinity, normal, hypersaline, brackish
Changes in surface salinity
Sources of salts…….. Compare to river water
How salts removed?
The Principle of Constant Proportions
Conservative and Nonconservative Constituents
Residence Time
Determining Salinity
Desalination
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10/5/2010
O C E A N 10
Fall 2010 Agenda
• QUIZ #3: is next week in lab (Nautical Charts only)
We’ll also start Lab #4, SFS etc…
• QUIZ #4: WEEK OF 10/19 (Cont Drift, SFS,
P. Tectonics and Marine Sediments! Wow.
• Tectonic Map with Earthquake Plots due week of
10/19.
• MIDTERM (Tuesday 10/26) Bring a scantron form
882, pencil, simple calculator. Other electronic
devices NOT permitted including ALL cell phones /
iPods / GPS wrist watches etc…..
The Origin of Seawater???
Juvenile Water?
Comets?
“Old Water, Young Containers”
Decreasing Rate Theory
Kuiper Belt, shown in green,
Units are AU’s (Astronomical Units)
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Seawater Chemistry
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Major Constituents of Seawater
& Salinity
Chapter 5: Unique properties of fresh water
Origin of Seawater???
Chapter 6: The 6 major constituents, trace elements
Salinity, normal, hypersaline, brackish
Changes in surface salinity
Sources of salts…….. Compare to river water
How salts removed?
The Principle of Constant Proportions
Conservative and Nonconservative Constituents
Residence Time
Determining Salinity
Desalination
Trace Elements
Hypersaline Bodies of water
• Salton Sea ~ 40 ppt (once 44 ppt)
• Mono Lake Salinity ~ 80 ppt
• Great Salt Lake Salinity ~ 120 – 270 ppt
• Dead Sea ~ 300 - 400 ppt
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Seawater Chemistry
The Dead Sea
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Chapter 5: Unique properties of fresh water
Origin of Seawater???
Chapter 6: The 6 major constituents, trace elements
Salinity, normal, hypersaline, brackish
Changes in surface salinity
Sources of salts…….. Compare to river water
How salts removed?
The Principle of Constant Proportions
Conservative and Nonconservative Constituents
Residence Time
Determining Salinity
Desalination
Surface Salinity Distribution
Surface Salinity Distribution
Sources of Salts?
Sources of Salts?
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10/5/2010
Major Constituents of Seawater
& Salinity
Major Constituents of Seawater
How Salts Removed?
How Salts Added / Removed?
Seawater Chemistry
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Chapter 5: Unique properties of fresh water
Origin of Seawater???
Chapter 6: The 6 major constituents, trace elements
Salinity, normal, hypersaline, brackish
Changes in surface salinity
Sources of salts…….. Compare to river water
How salts removed?
The Principle of Constant Proportions
Conservative and Nonconservative Constituents
Residence Time
Determining Salinity
Desalination
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10/5/2010
Major Constituents of Seawater
Figure 5.7
Determining Salinity
Refractometer
Hydrometer
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Desalination: converting salt water to freshwater
Figure 5.5
• Techniques:
Salinometer
– Reverse Osmosis (shown below) There are ~11,100 desalination
plants in 120 countries. This meets less than 0.15% of world’s
water needs. This would have to increase ~33 fold just to supply
5% of current water use.
• Where used:
– Middle East, Israel, Kuwait, Saudi Arabia
– Florida, California
– North Africa; Algeria
• Major Limitations:
– Expensive; it takes large amounts of Energy .
– Produces lots of waste water with high level of salt and other
minerals.
There are over
13,000 desalination
plants Worldwide that
produce more than 12
billion gallons of
water/day.
Largest in US is in
Tampa Bay Florida, 25
million gal/day
http://www.santacruzsentinel.com/ci_12129753
Figure 5.10
Water shortage in Algeria was eased in February 2008
as the $250 million Hamma Seawater Desalination
Plant (SWDP) was officially opened. The Hamma
SWDP purifies up to 200,000 cubic meters (53
million gallons) of seawater per day enough for 25
percent of the city’s daily needs.
Figure 5.11
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