Ch. 7- Acids and Bases Flashcards
an acid is a compound that…
- tastes sour
- causes litmus indicator dye to turn red
- dissolves active metals such as zinc and iron, producing hydrogen gas
- reacts with a base to form water and a salt
a base is a compound that…
- tastes bitter
- causes litmus indicator dye to turn blue
- feels slippery on the skin
- reacts with an acid to form water and a salt
acid-base indicator (litmus test)
a substance that is one color in acid and another color in base
Arrhenius acid-base theory
- acids are substances that form hydrogen ions (H+) and anions in water
- bases are substances that form hydroxide ions (OH-) when added to water
neutralization
the combination of H+ and OH- to form water, or the reaction of an acid and a base to produce a salt and (usually) water
salt
an ionic compound produced by the reaction of an acid with a base
limitation of Arrhenius theory
- a simple free proton does not exist in water solution; the H+ ion has such a high positive charge density that it is immediately attracted to a lone pair of electrons on an O atom of an H2O molecule, forming a hydronium ion (H3O+)
- it does not explain the basicity of ammonia and related compounds that also do not contain hydroxide ions
- it only applies to reactions in aqueous solution
creator of Arrhenius acid-base theory
Svante Arrhenius
creators of Brønsted-Lowry acid-base theory
J.N. Brønsted & T.M. Lowry
Brønsted-Lowry acid-base theory
- an acid is a proton (H+) donor
- a base is a proton (H+) acceptor
acidic anhydride
a substance, such as a nonmetal oxide, that reacts with water to form an acid
basic anhydride
a substance, such as a metal oxide, that reacts with water to form a base
amphiprotic
the ability of a substance, such as water, to either accept or donate a proton
strong acid
an acid that ionizes completely in water; a potent proton donor
weak acid
an acid that ionizes only slightly in water; a poor proton donor
name the strong acids
- sulfuric acid (H2SO4)
- hydrochloric acid (HCl)
- nitric acid (HNO3)
- hydrobromic acid (HBr)
- hydroiodic acid (HI)
- perchloric acid (HClO4)
strong base
a base that ionizes completely in water; a potent proton acceptor
weak base
a base that ionizes only slightly in water; a poor proton acceptor
name the strong bases
- all hydroxides of group 1A & group 2A EXCEPT for Be(OH)2
- the most common are sodium hydroxide or “lye” (NaOH) & potassium hydroxide (KOH)
name the most familiar weak base
ammonia (NH3)
pH
the negative logarithm of the H+ ion concentration, which indicates the degree of acidity or basicity of a solution
S. P. L. Sørensen
biochemist who first proposed the pH scale
conjugate acid-base pair
two molecules or ions that differ by one proton (H+ ion)
buffer solution
a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid that maintains a nearly constant pH when a small amount of strong acid or strong base is added
