Environmental Chemistry - Equilibrium
+
Introduction to Aquatic
Chemistry
Week 3 – September 19 2013
Environmental Chemistry - ENCV800401
+
Review: Biogeochemical cycle
Consists of:
Pool: Source and sink
Fate and transport
Substance and speciation
Equilibrium and kinetics
Mass balance
Quantifying through numerous method, including:
Equilibrium gases in water
+ Preview: Basic Aquatic Chemistry
: An Introduction
Properties of water
Air-water exchange
Acid-base reaction in natural waters
Precipitation and dissolution in natural waters
+
Properties of water
+
Thermodynamics of water
+
Property of water: Thermodynamics
Bond enthalphy :
ΔH OH= 463,5 kJ/mol
Hydrogen bond ΔHH---OH = 10-40 kJ/,mol
Ice: hydrogen bond intact, low density
(floats)
0oC: 12% Hydrogen bond broken
4oC: hydrogen bond broken, density higher
4-100oC: Hydrogen bond broken until 20% but greater kinetic energy causing thermal expansion thus density decrease.
+
+
+
Mengapa air menjadi pelarut yang baik? •Polar
•High dipole moment: 6,1 x 10-30 C m
•Forming X--- H2O bonds negative free energy process
(thermodynamically favorable)
+
Aqueous Chemistry – complex formation Since its such a good solvent, water contains many ions.
These ions are actually hydrated with water:
•
Acting as ligand
•
forming complexes with water or other ligands
+
Aqueous Chemistry – proton donor and acceptor
Water autoprotolysis
Water is amphiprotic: as proton donor or acceptor (bronsted acid/base) +
Aqueous Chemistry – redox properties Water oxidation
2H2O O2 (g) + 4H+(aq) + 4eWater reduction
2H2O + 2e- H2 (g) + 2OH- (aq)
+
Enthalpy of vaporization
What consequence do these numbers have on water’s property?
An unusually large amount of heat is consumed to evaporate water heat is adsorbed, temperature stability of surrounding +
Saturated water vapour pressure in
atmosphere
Introduction to Aquatic
Chemistry
Week 3 – September 19 2013
Environmental Chemistry - ENCV800401
+
Review: Biogeochemical cycle
Consists of:
Pool: Source and sink
Fate and transport
Substance and speciation
Equilibrium and kinetics
Mass balance
Quantifying through numerous method, including:
Equilibrium gases in water
+ Preview: Basic Aquatic Chemistry
: An Introduction
Properties of water
Air-water exchange
Acid-base reaction in natural waters
Precipitation and dissolution in natural waters
+
Properties of water
+
Thermodynamics of water
+
Property of water: Thermodynamics
Bond enthalphy :
ΔH OH= 463,5 kJ/mol
Hydrogen bond ΔHH---OH = 10-40 kJ/,mol
Ice: hydrogen bond intact, low density
(floats)
0oC: 12% Hydrogen bond broken
4oC: hydrogen bond broken, density higher
4-100oC: Hydrogen bond broken until 20% but greater kinetic energy causing thermal expansion thus density decrease.
+
+
+
Mengapa air menjadi pelarut yang baik? •Polar
•High dipole moment: 6,1 x 10-30 C m
•Forming X--- H2O bonds negative free energy process
(thermodynamically favorable)
+
Aqueous Chemistry – complex formation Since its such a good solvent, water contains many ions.
These ions are actually hydrated with water:
•
Acting as ligand
•
forming complexes with water or other ligands
+
Aqueous Chemistry – proton donor and acceptor
Water autoprotolysis
Water is amphiprotic: as proton donor or acceptor (bronsted acid/base) +
Aqueous Chemistry – redox properties Water oxidation
2H2O O2 (g) + 4H+(aq) + 4eWater reduction
2H2O + 2e- H2 (g) + 2OH- (aq)
+
Enthalpy of vaporization
What consequence do these numbers have on water’s property?
An unusually large amount of heat is consumed to evaporate water heat is adsorbed, temperature stability of surrounding +
Saturated water vapour pressure in
atmosphere