Chapter 19 Vocab Flashcards
acid dissociation constant (Ka)
the ratio of the concentration of the dissociated form of an acid to the undissociated form; stronger acids have larger Ka values than weaker acids
acidic solution
any solution in which the hydrogen-ion concentration is greater than the hydroxide-ion concentration
alkaline solution
a basic solution
amphoteric
a substance that can act as both an acid and a base
base dissociation constant (Kb)
the ratio of the concentration of the acid times the concentration of the hydroxide ion to the concentration of the base
basic solution
any solution in which the hydroxide-ion concentration is greater than the hydrogen-ion concentration
buffer
a solution in which the pH remains relatively constant when small amounts of acid or base are added; a buffer can be either a solution of a weak acid and the salt of a weak acid or a solution of a weak base with the salt of a weak base
buffer capacity
a measure of the amount of acid or base that may be added to a buffer solution before a significant change in pH occurs
conjugate acid
the particle formed when a base gains a hydrogen ion; NH4+ is the conjugate acid of the base NH3
conjugate acid-base pair
two substances that are related by the loss or gain of a single hydrogen ion; ammonia (NH3) and the ammonium ion (NH4+) are a conjugate acid-base pair
conjugate base
the particle that remains when an acid has donated a hydrogen ion; OH- is the conjugate base of the acid water
diprotic acid
any acid that contains two ionizable protons (hydrogen ions); sulfuric acid (H2SO4) is a diprotic acid
end point
the point in a titration at which the indicator changes color
equivalence point
the point in a titration where the number of moles of hydrogen ions equals the number of moles of hydroxide ions
hydronium ion (H3O+)
the positive ion formed when a water molecule gains a hydrogen ion
ion-product constant for water (Kw)
the product of the concentrations of hydrogen ions and hydroxide ions in water; it is 1X10-14 at 25°C
Lewis acid
any substance that can accept a pair of electrons to form a covalent bond
Lewis base
any substance that can donate a pair of electrons to form a covalent bond
monoprotic acids
any acid that contains one ionizable proton (hydrogen ion); nitric acid (HNO3) is a monoprotic acid
neutral solution
an aqueous solution in which the concentrations of hydrogen and hydroxide ions are equal; it has a pH of 7.0
neutralization reaction
a reaction in which an acid and a base react in an aqueous solution to produce a salt and water
pH
a number used to denote the hydrogen-ion concentration, or acidity, of a solution; it is the negative logarithm of the hydrogen-ion concentration of a solution
salt hydrolysis
a process in which the cations or anions of a dissociated salt accept hydrogen ions from water or donate hydrogen ions to water
self-ionization
a term describing the reaction in which two water molecules react to produce ions
standard solution
a solution of known concentration used in carrying out a titration
strong acid
an acid that is completely (or almost completely) ionized in aqueous solution
strong base
a base that completely dissociates into metal ions and hydroxide ions in aqueous solution
titration
process used to determine the concentration of a solution (often an acid or base) in which a solution of known concentration (the standard) is added to a measured amount of the solution of unknown concentration until an indicator signals the end point
triprotic acid
any acid that contains three ionizable protons (hydrogen ions); phosphoric acid (H3PO4) is a triprotic acid
weak acid
an acid that is only slightly ionized in aqueous solution
weak base
a base that reacts with water to form the hydroxide ion and the conjugate acid of the base
