Chapter 6 Flashcards
A substance that increases the concentration of H+ when added to water
Acid
Equilibrium constant for the reaction of an acid with H2O
Acid dissociation constant, Ka
One in which the activity of H+ is greater than the activity of OH-
Acidic solution
One that cannot donate protons (hydrogen ions) in an acid-base reaction
Aprotic solvent
The reaction in which two molecules of the same species transfer a proton from one to the other
Autoprotolysis
A substance that decreases the concentration of H+ when added to water
Base
The equilibrium constant for the reaction of a base with H2O
Base hydrolysis constant, Kb
One in which the activity of OH- is greater than the activity of H+
Basic solution
A proton (hydrogen ion) donor
Brønsted-Lowry acid
A proton (hydrogen ion) acceptor
Brønsted-Lowry base
Occurs when a salt is dissolved in a solution already containing one of the ions of the salt. The salt is less soluble than it would be in a solution without that surplus ion. An application of Le Châtelier’s principle
Common ion effect
Historical name for any ion containing two or more ions or molecules that are each stable by themselves
Complex ion
An acid and a base that differ only through the gain or loss of a single proton
Conjugate acid-base pair
Occurs when a substance whose solubility is not exceeded precipitates along with one whose solubility is exceeded
Coprecipitation
Equilibrium constant for a reaction of the type M + mX ⇌ MXn
Cumulative formation constant, Bn; Overall formation constant, Bn
A reaction in which an element in one oxidation state gives products containing that element in both higher and lower oxidation states
Disproportionation
One for which ΔH is positive; heat must be supplied to reactants for them to react
Endothermic reaction
The heat absorbed or released when a reaction occurs at constant pressure
Enthalpy change (ΔH)
A measure of “disorder” of a substance
Entropy
For the reaction aA + bB ⇌ cC + dD, (Cc * Dd)/(Aa * Bb)
Equilibrium constant (K)
One for which ΔH is negative; heat is liberated when products are formed
Exothermic reaction
The change in Gibbs free energy, ΔG, for any process at constant temperature is related to the change in enthalpy, ΔH, and entropy, ΔS, by the equation ΔG = ΔH - T ΔS, where T is temperature in kelvins. A process is spontaneous (thermodynamically favorable) if ΔG is negative
Gibbs free energy (G)
H+ (aq) or H3O+
Hydronium ion
A closely associated anion and cation, held together by electrostatic attraction. In solvents less polar than water, ions are usually found as ion pairs
Ion pair
If a system at equilibrium is disturbed, the direction in which it proceeds back to equilibrium is such that the disturbance is partially offset
Le Châtelier’s principle
One that can form a chemical bond by sharing a pair of electrons donated by another species
Lewis acid
One that can form a chemical bond by sharing a pair of its electrons with another species
Lewis base
An atom or a group attached to a central atom in a molecule; any group attached to anything else of interest
Ligand
Process in which a stoichiometric equivalent of acid is added of a base (or vice versa)
Neutralization
Defined as pH = - log[H+]
pH
Compound that can donate or accept more than one proton
Polyprotic acid or base
One with an acidic hydrogen atom
Protic solvent
Expression having the same form as the equilibrium constant for a reaction. However, the reaction quotient is evaluated for a particular set of existing activities (concentrations), which are generally not the equilibrium values. At equilibrium, Q = K.
Reaction quotient (Q)
An ionic solid
Salt
One that contains the maximum amount of a compound that can dissolve at equilibrium
Saturated solution
Equilibrium constant for the dissociation of a solid salt to give its ions in solution
Solubility product (Ksp)
The standard state of a solute is 1 M and the standard state of a gas is 1 bar. Pure solids and liquids are considered to be in their standard states. In equilibrium constants, dimensionless concentrations are expressed as a ratio of the concentration of each species to its concentration in its standard state
Standard state
Equilibrium constant for a reaction of the type ML(n-1) + L ⇌ MLn
Stepwise formation constant (Kn)
