Chapter 7-10 Flashcards
The value that replaces concentration in a thermodynamically correct equilibrium expression. The activity of X is given by Ax = [X]yx is the activity coefficient and [X] is the concentration
Activity, A
The number by which the concentration must be multiplied to give activity
Activity coefficient
A statement that the sum of all positive charge in solution equals the magnitude of the sum of all negative charge in solution
Charge balance
Gives the activity coefficient, y, of an ion as a function of ionic strength, u
Debye-Hückel equation
The region of solution around an ion or a charged particle. It contains an excess of oppositely charged ions
Ionic atmosphere
A measure of the total concentration of ions in solution
Ionic strength, u
Defined as pH = log [H+]
pH
Equilibrium constant for the reaction of an acid, HA, with H2O
Acid dissociation constant, Ka
The equilibrium constant for the reaction of a base, B, with H2O
Base hydrolysis constant, Kb
A mixture of a weak acid and its conjugate base; resists changes in pH when acids or bases are added
Buffer
A measure of the ability of a buffer to resist changes in pH; the larger the buffer capacity, the greater the resistance to pH change
Buffer capacity, B
An acid and a base that differ only through the gain or loss of a single proton
Conjugate acid-base pair
For the reaction of a base (B) with H2O, the fraction of base in the form BH+
Fraction of association, a
For the dissociation of an acid (HA), the fraction of acid in the form A-
Fraction of dissociation, a