CHEMISTRY PART 9 Acids and Bases

Acids  A compound that makes hydrogen ions when dissolved in water.  H + (aq)  Look for the (aq) (which means aqueous) to indicate the acid is dissolved in water.

Acids  To identify them:  Hydrogen + non-metal with the (aq) symbol.  Ex: HCl (aq) → H + (aq) + Cl - (aq)

Bases  A compound that makes hydroxide ions when dissolved in water.  OH - (aq)

Bases  To identify them:  Metal + hydroxide ion with the (aq) symbol.  Ex: NaOH (aq) → Na + (aq) + OH - (aq)

Naming Bases  You will know it is a base when you see OH and (aq). 1. Name the cation. 2. Name the anion (hydroxide) with the “ide” ending.

Naming Bases  Examples:  NaOH (aq)  sodium hydroxide  Ca(OH) 2 (aq)  calcium hydroxide

Naming Bases  Example:  KOH (aq)  potassium hydroxide

Naming Acids  With Simple Anions:  You will know it is an acid because of H and (aq). 1. Write the prefix “hydro”. 2. Add the name of the anion, shortened, with the ending “ic”. 3. Write the second word “acid”.

Naming Acids  Examples:  HCl (aq)  hydrochloric acid  HF (aq)  hydrofluoric acid

Naming Acids  Examples:  HBr (aq)  hydrobromic acid  HI (aq)  hydroiodic acid

Naming Acids  With Polyatomic Ions: 1. Name the polyatomic ion which is shortened. “ic” if it ends in “ate”. “ous” if it ends in “ite”. 2. Write the second word acid.  Ex: HNO 3(aq)  nitrate ion = nitric acid  Ex: HNO 2(aq)  nitrite ion = nitrous acid

Naming Acids  Examples:  H 2 CO 3(aq)  carbonate ion  carbonic acid  H 2 SO 4(aq)  sulfate ion  sulfuric acid

Naming Acids  Example:  H 2 SO 3(aq)  sulfite ion  sulfurous acid

Practice  Worksheet  # 1 and 2

Formula Writing for Acids 1. Determine the anion. 2. Since it is an acid the cation is H Use circle method or cross method to determine the subscripts.

Formula Writing for Acids  Example:  Sulfuric acid  Sulfuric  sulfate  SO 4 2-  Acid  hydrogen  H +  H 2 SO 4

Formula Writing for Acids  Example:  Phosphoric acid  Phosphate  PO 4 3-  Cation  H +  H 3 PO 4

Practice  Worksheet  # 3  Page 165 # 17 – 20