Acids and Bases - CHEM

name four distinct, unique characteristics of all acids

ph < 7, contain H+, react with metals, found in foods, taste sour

name four distinct unique characteristics of all bases

ph > 7, contain OH-, react with organic material, used in cleaning products, taste bitter

What characteristics do they both have in common?

both electrolytic and caustic

what are the differences between Arrhenius acid and base definitions

arrhenius acid: substance that produces H+ ions in solutions

arrhenius base substance that produces OH- ions in solutions

bronsted acid: H+ (proton) donor

bronsted base: H+ (proton) acceptor

what makes an acid or base weak? How are “K” values interpreted?

Degree of dissociation; strong, completely dissociate; weak, partially dissociate; strongest species have large K values (small negative exponents)

what is neutralization?

stoichiometrically proportional reaction between an acid and a base in which a salt (and sometimes water) is produced.

what is titration?

a solution of a known concentration is used to determine the concentration of an unknown substance.

what are indicators? how do you select which indicator to use?

Substance that changes color as pH changes. Select one with an end point near the equivalence point of the reaction.

what is the difference between equivalence point and end point?

equivalence point: point in a reaction when [H3O+] = [OH-]

end point: pH at which the indicator changes color

what is hydrolysis? Why don’t all salts hydrolyze?

A process in which a substance dissociates in, then reacts with H2O.

Salts formed from strong acids and strong bases that have weak conjugates and that do not react with water.

What are buffers? How do they work?

Resists a change in pH when OH- or H+ are added. Solution consists of a weak acid and its salt or weak base and its salt. The common ion causes equilibrium shifts to maintain H3O+/OH- levels.