Section 2.4—Defining, Naming & Writing Acids & Bases

Section 2.4—Defining, Naming & Writing Acids & Bases We need to know what acids behave when talking about ant-acids!

Acids

H +1 +1 H water O O H H H H Acids – Arrhenius Definition • Produce Hydronium ion (H3O+1) in water • Hydronium ion is water + a hydrogen cation By this definition, if an acid is to give a H+1 to water, then all acids will have hydrogen as the cation (first element written).

- H O H H How do Acids produce Hydronium? water acid Hydrogen cation with some anion

- H O H H How do Acids produce Hydronium? +1

- H O H H How do Acids produce Hydronium? +1 Hydronium ion Anion

Naming Acids

Naming non-oxygen Acids • These compounds have: • Start with “H” (more than 1 “H” is OK, too). • Do not contain oxygen • To name these compounds: • Use “hydro____ic acid” • Fill in the blank with the anion’s name without the last syllable

Example #1 HBr

Example #1 It’s an acid Hydrogen cation HBr Hydrobromic acid Bromine No oxygen Use “hydro___ic”

Naming Oxygen Acids • These compounds have: • Start with “H” (more than 1 “H” is OK, too). • Do contain oxygen • To name these compounds: • Use “___ic acids” for “-ate” anions • Use “___ous acids” for “-ite” anions Do not use “hydro” with these…the word “acid” is how you know it begins with hydrogen, not “hydro-”

Example #2 H2SO3

Example #2 It’s an acid Hydrogen cation H2SO3 Sulfite ion “-ite” ion Use “___ous” acid Sulfurous acid

Example #3 H2SO4

Example #3 It’s an acid Hydrogen cation H2SO4 Sulfate ion “-ate” ion Use “___ic” Sulfuric acid

Let’s Practice HCl HNO3 H2S H3PO3 Example: Write the name for the following compounds

Let’s Practice HCl HNO3 H2S H3PO3 Hydrochloric acid Nitric acid Hydrosulfuric acid Phosphorous acid Example: Write the name for the following compounds

Writing Acid Formulas

“Hydro-” acids • To write these formulas: • The cation is H+1 • Write the anion and charge • Balance the charges by adding the appropriate subscript to the hydrogen cation

Example #4 Hydrofluoric acid

Example #4 H+1 Hydrogen cation Hydrofluoric acid Does not contain oxygen F-1

Example #4 H+1 Hydrogen cation Hydrofluoric acid Does not contain oxygen H+1F-1 F-1 +1 + -1 = 0 HF The compound is neutral. Subscripts are not needed

NON “Hydro-” acids • To write these formulas: • The cation is H+1 • If it is an “-ic” acid, the anion is the “-ate” polyatomic ion • If it is an “-ous” acid, the anion is the “-ite” polyatomic ion • Add subscript to the hydrogen cation to balance charges

Example #5 Carbonic acid

Example #5 H+1 Hydrogen cation Carbonic acid From the “___ate” anion CO3-2

Example #5 H+1 H+CO32- Hydrogen cation +1 + -2 = -1 Carbonic acid H+H+CO32- +1 + 1 + -2 = 0 From the “___ate” anion CO3-2 H2CO3

Example #6 Nitrous acid

Example #6 H+1 Hydrogen cation Nitrous acid From the “___ite” anion NO3-1

Example #6 H+1 Hydrogen cation Nitrous acid H+NO2- From the “___ite” anion +1 + -1 = 0 NO3-1 HNO2

Let’s Practice Phosphoric acid Hydroiodic acid Carbonous acid Perchloric acid Example: Write the formula for the following acids

Let’s Practice Phosphoric acid Hydroiodic acid Carbonous acid Perchloric acid H3PO4 HI H2CO2 HClO4 Example: Write the formula for the following acids

Bases

-1 O H Bases – Arrhenius Definition • Bases produce the hydroxide ion in water Hydroxide Ion

Naming & Writing Bases

Naming Bases • Most bases are just ionic compounds with “hydroxide” as their anion • The most common exception to this is ammonia • NH3 (ammonia) is a base even though it doesn’t contain “-OH” as the anion

Example #7 NaOH

Example #7 Sodium NaOH Sodium Hydroxide Hydroxide

Let’s Practice Ca(OH)2 KOH Sr(OH)2 Copper (II) hydroxide Magnesium hydroxide Example: Write the formula or name for each

Let’s Practice Ca(OH)2 KOH Sr(OH)2 Copper (II) hydroxide Magnesium hydroxide Calcium hydroxide Potassium hydroxide Strontium hydroxide Cu(OH)2 Mg(OH)2 Example: Write the formula or name for each

Section 2.4—Defining, Naming & Writing Acids & Bases