9 - Acids, Bases, and Salts

arrhenius acid

any substance that provides H⁺ ions when dissolved in water

arrhenius base

any substance that provides OH^- ions when dissolved in water

Bronsted acid

any hydrogen containing substance that is capable of donating a proton (H⁺) to another substance

Bronsted base

any substance that is capable of accepting a proton (H⁺) from another substance

conjugate base

the species remaining when a Brønsted acid donates a proton

conjugate acid-base pair

a Bronsted acid and its conjugate base

neutral

a term used to describe any water solution in which the concentrations of H₃O⁺ and OH^- are equal

• a water solution with pH = 7

ion product of water

the equilibrium constant for the dissociation of pure water into H₃O⁺ and OH^-

acidic solution

a solution in which the concentration of H₃O⁺ is greater than the concentration of OH^-

• a solution in which the pH is less than 7

basic solution

a solution in which the concentration of OH^- is greater than the concentration of H₃O⁺

• a solution in which the pH is greater than 7

pH

the negative logarithm of the molar concentration of H⁺ (H₃O⁺) in a solution

activity series

a tabular representation of the tendencies of metals to react with H⁺

neutralization reaction

a reaction in which an acid and base react completely, leaving a solution that contains only a salt and water.

salt

a solid crystalline ionic compound at room temperature that contains the cation of a base and the anion of an acid

cation

a positively charged ion

anion

a negatively charged ion

hydrate

a salt that contains specific numbers of water molecules as part of the solid crystalline structure

water of hydration

the water retained as part of the solid crystalline structure of some salts

equivalent of salt

the amount that will produce 1 mol of positive (or negative) electrical charges when dissolved and dissociated

strong acids and bases

the acids and bases that dissociate (ionize) completely when dissolved to form a solution

weak acids and bases

the acids and bases that dissociate (ionize) less than completely when dissolved to form a solution

acid dissociation constant

the equilibrium constant for the dissociation of an acid

monoprotic acid

an acid that gives up only one proton (H⁺) per molecule when dissolved

diprotic acid

an acid that gives up two protons (H⁺) per molecule when dissolved

triprotic acid

an acid that gives up three protons (H⁺) per molecule when dissolved

titration

an analytical procedure in which one solution (often a base) of known concentration is slowly added to a measured volume of an unknown solution (often an acid)

equivalence point of titration

the point at which the unknown solution has exactly reacted with the known solution

endpoint of titration

the point at which the titration is stopped on the basis of an indicator color change or pH meter reading

hydrolysis reaction

any reaction with water

buffer

a solution with the ability to resist changing pH when acids (H⁺) or bases (OH^-) are added

buffer capacity

the amount of acid (H⁺) or base (OH^-) that can be absorbed by a buffer without causing a significant change in pH

Henderson-Hasselbalch equation

a relationship between the pH of a buffer, pK_a, and the concentrations of acid and salt in the buffer