Chem Exam 2 (part 2)

PH and POH

• PH = measure of acid strength

• POH = measure of base strength

Basic

• high PH + low POH

Acidic

• Low PH + high POH

PH > 7

• basic

PH < 7

• acidic

P of Ka, Kw, Kp

PKw = - log (Kw)

PH + POH

= 14

larger the Ka or smaller the PKa

• the stronger the acid

10^-PH = X

• plug into products spot

C₅H₅N or NH₃

• weak bases

Strength of Binary Acid

• ability to release proton H+

• determined by electronegativity - greater the electronegativity the greater the acid strength

• size and bond length affect acid strength

• inc radius size = inc bond length = inc chance of losing protons = inc acid strength

Electronegativity

• increases right and up a row

ionic radius inc

• inc left and down a row

strength of oxyacids

• oxyacid ex: HNO₃

• determined by electronegativity of central atom and number of terminal oxygen atoms

• less oxygen atoms on central atom = weaker the acid

• the greater the electronegativity = stronger the acid

acid strength determined by

• electronegativity, atomic size, oxidation number

buffer

• weak acid and conjugate base

• conjugate acid + weak base

• maintain PH of a solution when adding small amounts of acids and bases

• ideal PH = PKa

• look for weak acids and bases

neutral anions

• strong acids

neutral cations

• strong bases

basic anions

• weak acids

acidic cations

• weak bases

strong acid and strong base

• PH = 7

Strong acid and weak base

• PH < 7

weak acid and strong base

• PH > 7