The Chemistry of Seawater Chapter 6. The pH of Seawater H + Hydrogen cation OH - Hydroxide anion H...
-
Upload
hilda-curtis -
Category
Documents
-
view
222 -
download
0
Transcript of The Chemistry of Seawater Chapter 6. The pH of Seawater H + Hydrogen cation OH - Hydroxide anion H...
The Chemistry of Seawater
Chapter 6
The pH of Seawater
H+
Hydrogen cation OH-
Hydroxide anion
H+ = OH- H+ < OH- H+ > OH-
Neutral Alkaline Acidic
pH Measurement
Buffering Capacity of CO2
Buffer Substance that prevents sudden, or large,
changes in acidity or alkalinity of a solution
CO2 + H2O H2CO3 H+ + HCO3- 2H+ + CO3
2-
Too basicToo acidic
Salinity
Units of Concentration Weight Volume Moles
Ocean Salinity
Measured in grams of salt per kilogram of seawater 1kg of seawater is made up of 965 g of
water and 35 g of salt 35‰
Dissolved Salts
Ionic bonds
Major Constituents
Conservative ions
Nonconservative ions
Sources of Salt
Chemical weathering Riverine input Most cations Anions from Earth’s mantle
Sources of Salt
Volcanic gases
Hydrogen sulfide Sulfur dioxide Chlorine
Sources of Salt
Hydrothermal vents Discovered in 1977 Geyser on the seafloor Spews super-hot, mineral-rich water Very biodiverse
Sources of Salt
Hydrothermal vents Black Smokers
Hottest of the vents Spew iron and sulfide, which combine to form
iron monosulfide
White Smokers Cooler temp Barium, Calcium and Silicon
Regulating the Salt Balance
Rivers vs. Oceans
Residence Time
RT =
Amount of ion
Rate of sup/removal
Principle of Constant Proportions
Constant composition 1819 – Alexander Marcet 1865 – Georg Forchhammer Challenger expedition
William Dittmar Chloride ion
Determining Salinity
Electrical conductivity More ions = greater
conductance
Salinometer
Salinity (‰) = 1.80655 X chlorinity (‰)