Midterm 2 Flashcards
Covalent bonding of water
- Hydrogen needs one electron to fill the inner shell.
* Oxygen needs two electrons to fill its outer shell.
- Surface tension
Water would rather interact with itself than the air
via hydrogen bonding
leads to clustering of water molecules
gives water high surface tension
Heat
is thermal energy transferred from a hotter system that is in contact with a cooler system.
Temperature
is a measure of the kinetic energy of the moving molecules.
The heat capacity of a substance
amount of energy required to raise temperature of 1 g of substance by 1 degree Celsius.
* Water has a high heat capacity
Latent heat:
hidden heat due to hydrogen bonds
* Between the phases, heat and temperature don’t line up
* Latent heat of melting 80 calories
* Latent heat of evaporation 540
Global thermostatic effects
Movement of water redistributes heat and moderates climate.
* At low latitudes, evaporation removes heat from the oceans. * At high latitudes, condensation and precipitation add heat to the atmosphere.
Seawater compcompositionostion
96.5% water
3.5% salt
99.4% major salt (cssmcp)
0.6 minor salt (bbsbf)
Nutrients
Trace metals
Major salts
(CSSMCP) Chloride 55.23% Sodium 30.59% Sulfate Magnesium Calcium Potassium 99.4%
Minor salts
BBSBF Bicarbonate 0.4 Bromide Strontium Bron Fluoride
Typical sea water has __ of salt per one thousand grams of sea water.
35g
Conservative ions:
Major constituents vary little over time at most localities.
Nutrients in seawater
occur at much lower concentration are non conservative Nutrients are actively used by biology. NPSI Nitrogen Phosphorus Silicon Iron
Trace Metals
iZAUG Iodine Zinc Aluminum Uranium Gold
Salinity
The total mass expressed in grams of all substances dissolved in 1 kilogram of seawater,
average is 35g
Salinity is variable
true
* Salinity depends on evaporation, precipitation and runoff.
high salinity vs low salinity conditions
- High salinity: Hot and dry climates
* Low salinity: Damp and cool climates, close to a river
Proportions of salts do not vary
true
The ratio of any two major salt constituents in ocean water is constant and independent of salinity
Measuring cl abundance
Chemists choose to measure Cl to measure salinity because it is the most abundant and easy to measure
* Measure Chlorine abundance by determining conductivity of the water
salt sources
- Rivers
- Volcanoes
- Hydrothermal activity
salt Sinks
:
* Deposition in sediments * Deposition on land * Biological processes * Hydrothermal activity
the dominant input of salt into ocean
- Rivers are the dominant input of salts to the ocean
* Salt ions dissolved in ocean water are derived primarily from the chemical weathering of rocks on land
- Ion Proportions in Fresh Water
- Bicarbonate/carbonate: Highest percentage, 50
- Chloride: Low percentage
- Potassium: lowest percentage
- Ion proportions in Seaways Water
- Chloride: Highest percentage, over 50
- Bicarbonate/carbonate: Lowest percentage
Potassium: low percentage
- Bicarbonate/carbonate: Lowest percentage
___ and _____ have a high residence time
- Calcium and Silicon are use to construct shells, so they do not stay around as long.
____ has the highest residence Time
- Sodium is not removed rapidly.
______ and _____ have the shortest residence Time
- Iron and Aluminum attach to particle surfaces and sink out rapidly
Temperature and density relationship
- Not a linear relationship
- High temperatures: Freshwater has a low density (decreases)
- Cold temperatures: Freshwater has a high density (increases)
- Ice: Past 3.98 degrees density decreases
High temperatures: Freshwater has a ___ density
low
Cold temperatures: Freshwater has a____ density
high
cluster effect:
Increases the volume, and therefore decreases the density
* Passed the point of water’s maximum density (pmax) 3.98
Salinity
- At low salinity: Low density, less material (mass) in same volume
- At high salinity: High density, more material (mass) in same volume
- Linear relationship
At low salinity:___ density,
low
- Fall overturn:
- The process of surface water loosing heat to atmosphere and sinking
- Surface waters cools, becoming more dense and sink, mixing the water
- Enter water column becomes Isothermal (all the same temperature) at 3.98
- Density no longer increases, Water no longer sinks and continues to cool until ice forms on the surface
Thermocline:
Depth interval where the temperature changes rapidly
* Temperature decreases rapidly with a depth of about 20m * Temperatures are fairly constant below the thermocline, around 4-8 degrees
- Increasing salinity_____ heat capacity
Decreases
- Increasing salinity _____ the temperature of maximum density
lowers
* No longer 3.98, becomes significantly lower * Function of how much salt is added * Salt interfere with the hydrogen bonds and impede on the formation of tetrahedrons and clusters
- Adding salt _____ the freezing point
lowers
* The freezing point of seawater is well below 0 degrees * Because of how salts impress the formation of hydrogen bonds and the formation of clusters * Freezing point depressing = -0.054 x salinity (%o)
how is Frozen seawater is different than frozen freshwater
- Saltwater ice is more brittle
* Dissolved salt in the water is excluded from crystalline lattice
- Increasing pressure _____ density
increases
* Linear relationship
- T-S Diagram: Temperature Salinity diagram
- Lines of constant densities over a range of temperatures and salinities
- Temperature y axis
- Salinity x axis
- Mixing two water masses of identical DENSITIES can produce denser water
- Halocline:
Zone of rapidly changing salinity with increasing depth
* Often found near the coat * Especially near estuaries that dump fresh water * Fresh water floats
- Pycnocline
: A zone of rapidly changing density with increasing depth
* A function of temperature and salinity
