Chapter 20 Notes, part I Acids and Bases

What are some common acids? Vinegar (acetic acid) Carbonated drinks (carbonic and phosphoric acid) Citrus fruits (citric acid) Car battery (sulfuric acid)

What are some common bases? Milk of magnesia (an antacid containing magnesium hydroxide) Many cleaning products (ammonia, etc)

What properties do acids have? Acids tend to be: Tart or sour tasting In solution, they are an electrolyte They can cause chemical dyes (called indicators) to change colors

What properties do bases have? Bases tend to be: Bitter tasting Slippery feeling when touched Able to neutralize an acid

Salts Salts are ionic compounds formed from a cation (other than H + ) and an anion (other than OH - ).  any ionic compound that is not classified as an acid or base.  taste salty! Electrolytes Electrolytes are substances that can conduct electricity when dissolved in water.  electricity is the flow of electrons (e-).  cations (+) allow (-) e- to flow through water. There are three classes of electrolytes…  acids, bases and salts! Good electrolytes ionize (dissociate) completely (100%) in water.  HNO 3, HCl, NaOH and KOH all ionize completely

So what IS an acid? An acid is a compound that produces hydrogen ions (H + ) when dissolved in water. The formula would be H a X, where X is any monatomic or polyatomic anion and a is the anion’s charge.

Obj. 5-6…Acid Nomenclature Two types of acids…binary and ternary Binary acids (two capital letters)…  ‘hydro______ic acid’  HF = hydrofluoric acid  H 2 S = hydrosulfuric acid Ternary acids (three or more capital letters)…  ‘ate – ic / ite – ous’  NO HYDRO!!!  anions ending in ‘ate’ change to ‘ic’…anions ending in ‘ite’ change to ‘ous’!  H 2 SO 4 = sulfuric acid sulfate  HNO 2 = nitrous acid nitrite

Obj. 5-6 cont… To write formulas for acids…  formula starts with H  look at oxidation #s to see if subscripts are needed prefix ‘hydro’ = only 2 capital letters no ‘hydro’ = H + polyatomic ion (ate – ic / ite – ous)  oxalic acid = H +1 and C 2 O 4 -2 =  Ex… H 2 C 2 O 4 H 2 C 2 O 4  hydroiodic acid = H +1 and I -1 = HI HI  sulfurous acid = H +1 and SO 3 -2 = H 2 SO 3 H 2 SO 3

Naming an acid When the name of the anion (X) ends in –ide, the name begins with hydro-, then the stem of the anion, then the name ends with –ic acid instead of -ide. When the name of the ion ends in –ite, then the name would be the stem of the anion and the suffix –ous acid instead of –ite. When the name of the ion ends in –ate, then the name would be the stem of the anion and the suffix –ic acid instead of-ate.

Then what is a base? A base is a compound that produces hydroxide (OH - ) ions when in solution. Bases are named the same way that an ionic compound would be named.

Name the following acids and bases:

HClO 3 Chloric Acid

H 3 PO 4 Phosphoric Acid

HF Hydrofluoric Acid

HNO 3 Nitric Acid

KOH Potassium Hydroxide

H 2 SO 4 Sulfuric Acid

Ba(OH) 2 Barium Hydroxide

HCN Hydrocyanic Acid

H 3 PO 3 Phosphorous Acid

HClO 4 Perchloric Acid

HBr Hydrobromic Acid

H 2 CO 3 Carbonic Acid

Al(OH) 3 Aluminum Hydroxide

Write the formula for the following acids and bases:

Hydrochloric Acid HCl

Barium Hydroxide Ba(OH) 2

Sulfuric Acid H 2 SO 4

Phosphorous Acid H 3 PO 3

Sodium Hydroxide NaOH

Hydroiodic Acid HI

Nitrous Acid HNO 2

Ammonium Hydroxide NH 4 OH

Chromic Acid H 2 CrO 4

Permanganic Acid HMnO 4

Hydrobromic Acid HBr

Lithium Hydroxide LiOH

Nitric Acid HNO 3

Thiocyanic Acid HSCN