ACIDS, BASES, AND pHACIDS, BASES, AND pH

pp. 39-44pp. 39-44

WaterWaterPolar (covalent) compoundPolar (covalent) compound

• Water has a positive (+) Water has a positive (+) and negative (-) “pole” and negative (-) “pole”

• (+) is due to H and (-) is O (+) is due to H and (-) is O

• acts like a magnet with + acts like a magnet with + attracted to –attracted to –

• pulls apart molecules like pulls apart molecules like NaCl (NaCl (ionic bondionic bond))

WaterWaterBondingBonding

• covalent bondscovalent bonds hold hold HH22O togetherO together

• hydrogen bondshydrogen bonds hold molecules of Hhold molecules of H22OO

• Covalent > HydrogenCovalent > Hydrogen

Acids and BasesAcids and Bases • HH22O = waterO = water

• HH++ = hydrogen ion = hydrogen ion

• OHOH- - = hydroxide ion= hydroxide ion

Acids and BasesAcids and Bases • HH22O O H H++ + OH + OH--

• HH++ reacts with H reacts with H22OO

HH22O + HO + H++ H H33OO+ + ((hydroniumhydronium))

• HH33OO+ + more commonly written as H more commonly written as H++

• AcidsAcids: H: H++ > OH- > OH-

EX. HCl, HEX. HCl, H22SOSO44

• BasesBases: OH: OH-- > H > H++

EX. NaOH, Mg(OH)EX. NaOH, Mg(OH)22

pHpH ppower of ower of HHydroniumydronium

• measures acidity (from 0-14) and measures acidity (from 0-14) and how much Hhow much H33OO++/H/H+ + is present. The is present. The closer to 0, the more the Hcloser to 0, the more the H33O O ++/H/H++

0 up to 7 = acid 0 up to 7 = acid 7 = neutral7 = neutral over 7 = base/alkalineover 7 = base/alkaline• Can use indicators to tell the pH Can use indicators to tell the pH

( phenol red, pH paper, litmus, BTB)( phenol red, pH paper, litmus, BTB)