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Glossary of Chemical Oceanography Terms
Debye–Hückel Equation: An equation that describes the theoretical concentration behavior of electrolytes in dilute solutions. For the activity coefficient of an electrolyte,
the Debye- Hückel limiting law is given by ln γ = –0.509 I 0.5 /(1 + 0.33 I 0.5 ), where I is
the ionic strength.
Dielectric Constant: The ratio of the capacitance of a solution to a vacuum.
Dipole/ Dipole Interactions: The interaction between adjacent molecules caused by the
attraction of the areas of charge separation (dipoles).
Dipole Moment: A measure of the charge separation in a molecule. It is defined as the
product of the electrostatic charge times the distance between the two charges.
Dipole moments are measured in units of Debye (1 × 10 –8 esu cm).
Dissociation Constant: The thermodynamic constant for the dissociation of an ion pair,
complex, or acid (AB → A +B, K D = [A][B]/[AB]).
E h –pH Diagrams: The diagrams showing the relation of pH and E h (oxidation potential)
of species.
Electrical Conductance: The ability of a solution to carry an electrical current (conductance
= 1/resistance; measured in ohm –1 ).
Electrical Potential, E h : The electrical potential generated for a oxidation–reduction
reaction (related to the Nernst equation, E h = E h ° + (RT/ nF)ln a ox / a red, where a is
the activity).
Electrostriction: The decrease in the volume due the interactions of a solute with a solvent. The water molecules near an ion have a higher density than the bulk water.
Entropy of Hydration: The change in the amount of order or disorder in a system as a
result of hydration.
Equilibrium: A state when the forward and backward reactions are equal. The rate of the
products being formed is equal to the rate of the reactants being used.
Fraction of Free Ions: The fraction of ions that are not in a complex or ion pair (α MX =
[M] F /[M] T ).
Free Energy of Hydration: The free energy involved in the interaction of water with a solute.
Free Ions: Ions in solution that are only hydrated by water molecules (no interactions with
other ions).
Freezing Point Depression: The decrease in the freezing temperature of a liquid as the
result of the presence of a solute.
Heat Capacity: The amount of heat (calories or joules) needed to raise the temperature of
a solid or liquid substance by 1 K.
Heat Conduction: The ability of a substance to transport heat.
Heat of Crystal Lattice Formation: The energy involved in the formation of a crystal lattice.
Heat of Dissociation: The energy involved in dissociation of a molecule into ions.
Heat of Evaporation: The amount of heat (calories or joules) released or taken up on the
change of state of a liquid–vapor or vapor–liquid.
Heat of Formation: The energy involved in the formation of a compound formed from its
constituent elements.
Heat of Fusion: The amount of heat (calories or joules) released or taken up on the change
of state of a solid–liquid or liquid–solid.
Heat of Hydration: The energy involved in hydrating ions.
Heat of Ionization: The energy involved in the dissociation of a molecule into ions.
Heat of Solution: The energy change produced when a substance dissolves in a solvent.
Heat of Sublimation: The energy involved in the conversion of a solid to a gas.
Henry’s Law: The partial pressure of a gas is directly proportional to the concentration
(P A = k m A or k’ X A , where m is the molality and X is the mole fraction).
Glossary of Chemical Oceanography Terms
Debye–Hückel Equation: An equation that describes the theoretical concentration behavior of electrolytes in dilute solutions. For the activity coefficient of an electrolyte,
the Debye- Hückel limiting law is given by ln γ = –0.509 I 0.5 /(1 + 0.33 I 0.5 ), where I is
the ionic strength.
Dielectric Constant: The ratio of the capacitance of a solution to a vacuum.
Dipole/ Dipole Interactions: The interaction between adjacent molecules caused by the
attraction of the areas of charge separation (dipoles).
Dipole Moment: A measure of the charge separation in a molecule. It is defined as the
product of the electrostatic charge times the distance between the two charges.
Dipole moments are measured in units of Debye (1 × 10 –8 esu cm).
Dissociation Constant: The thermodynamic constant for the dissociation of an ion pair,
complex, or acid (AB → A +B, K D = [A][B]/[AB]).
E h –pH Diagrams: The diagrams showing the relation of pH and E h (oxidation potential)
of species.
Electrical Conductance: The ability of a solution to carry an electrical current (conductance
= 1/resistance; measured in ohm –1 ).
Electrical Potential, E h : The electrical potential generated for a oxidation–reduction
reaction (related to the Nernst equation, E h = E h ° + (RT/ nF)ln a ox / a red, where a is
the activity).
Electrostriction: The decrease in the volume due the interactions of a solute with a solvent. The water molecules near an ion have a higher density than the bulk water.
Entropy of Hydration: The change in the amount of order or disorder in a system as a
result of hydration.
Equilibrium: A state when the forward and backward reactions are equal. The rate of the
products being formed is equal to the rate of the reactants being used.
Fraction of Free Ions: The fraction of ions that are not in a complex or ion pair (α MX =
[M] F /[M] T ).
Free Energy of Hydration: The free energy involved in the interaction of water with a solute.
Free Ions: Ions in solution that are only hydrated by water molecules (no interactions with
other ions).
Freezing Point Depression: The decrease in the freezing temperature of a liquid as the
result of the presence of a solute.
Heat Capacity: The amount of heat (calories or joules) needed to raise the temperature of
a solid or liquid substance by 1 K.
Heat Conduction: The ability of a substance to transport heat.
Heat of Crystal Lattice Formation: The energy involved in the formation of a crystal lattice.
Heat of Dissociation: The energy involved in dissociation of a molecule into ions.
Heat of Evaporation: The amount of heat (calories or joules) released or taken up on the
change of state of a liquid–vapor or vapor–liquid.
Heat of Formation: The energy involved in the formation of a compound formed from its
constituent elements.
Heat of Fusion: The amount of heat (calories or joules) released or taken up on the change
of state of a solid–liquid or liquid–solid.
Heat of Hydration: The energy involved in hydrating ions.
Heat of Ionization: The energy involved in the dissociation of a molecule into ions.
Heat of Solution: The energy change produced when a substance dissolves in a solvent.
Heat of Sublimation: The energy involved in the conversion of a solid to a gas.
Henry’s Law: The partial pressure of a gas is directly proportional to the concentration
(P A = k m A or k’ X A , where m is the molality and X is the mole fraction).