Chapter 15 Acids and Bases

Acids Vocabulary – Hydrogen ion = H +1 = Proton General Properties of Acids: Acids have a sour taste (ex – citrus fruits, soda, vinegar) Many acids contain hydrogen. Some react with active metals to liberate hydrogen gas (Remember Zn + HCl ) Acids change the color of indicators Acids react with base to produce salt and water HCl + NaOH  NaCl + H 2 O Acids are electrolytes

Acid Definitions An acid may fit one, two or all three definitions Traditional definition (Arrhenius) – Acids contain Hydrogen ion(s) and give them up when in water HCl (g) ---> H + (aq) + Cl - (aq) H2OH2O VIDEO!! VIDEO CLIP!!

Acid Definitions An acid may fit one, two or all three definitions Bronsted definition– Acids are proton DONORS -Similar to Arrhenius definition, but there must be another substance for the acid to give the proton to. HCl (g) + H 2 O (l) --> H 3 O + (aq) + Cl - (aq)

Acid Definitions An acid may fit one, two or all three definitions Lewis definition– Acids are electron pair acceptors -The acid might not even have a hydrogen in it +  Accepts an e- pair from NH 3

Strong Acid: -Ionizes nearly 100% Examples to memorize: -HCl (hydrochloric acid) -H 2 SO 4 (sulfuric acid) when losing the first proton HCl  H + + Cl -

Weak Acid: -Ionizes less than 100% -Lots of the unionized acid will remain Examples to memorize: -HF (hydrofluoric acid) -HCH 3 COO / CH 3 COOH (acetic acid) HF H + + F - REMEMBER – STRONG/ WEAK DOES NOT RELATE TO DANGER LEVEL!!

Classifying Acids Monoprotic – 1 proton to lose ex – HCl (hydrochloric acid) Polyprotic – More than 1 proton to lose Diprotic – 2 protons to lose ex – H 2 SO 4 (sulfuric acid) Triprotic – 3 protons to lose ex – H 3 PO 4 (phosphoric acid)

Acid Structure and Naming Binary Acids – H and one other atom example – HF, HI, HCl Naming – Hydro --- ic acid example – hydrofluoric acid hydroiodic acid hydrochloric acid

Oxyacids – Have oxygen -Come from the eight -ates ION NAMEACID NAME 2 LESS OHYPO – ITEHYPO – OUS ACID 1 LESS O ITEOUS ACID MEMORIZEDATEIC ACID 1 MORE OPER – ATEPER – IC ACID Examples: FROM SULFATE (SO 4 -2 ) H 2 SO 2 H 2 SO 3 H 2 SO 4 H 2 SO 5 Hyposulfurous Acid Sulfurous Acid Sulfuric Acid Persulfuric Acid

**Know the acids from sulfate, nitrate, chlorate, phosphate!! Examples – sulfuric, sulfurous, nitric, perchloric, phosphoric, etc. *Some Other Common Acids to Know: HydrochloricHydrofluoricHydroiodicHydrobromicAcetic

Bases General Properties of Bases: -Bases have a bitter taste (soap, bakers choc) -Dilute aqueous solutions feel slippery (soap) -Bases change the color of indicators -Bases react with acids to produce salts and water HCl + NaOH  NaCl + H 2 O -Bases are electrolytes

Base Definitions A base may fit one, two or all three definitions Traditional definition (Arrhenius) – A base contains Hydroxide ion(s) and gives them up when in water KOH (s)  K + (aq) + OH - (aq) H2OH2O

Base Definitions An acid may fit one, two or all three definitions Bronsted definition– Bases are proton ACCEPTORS HCl (g) + H 2 O (l)  H 3 O + (aq) + Cl - (aq) BASE

Base Definitions An acid may fit one, two or all three definitions Lewis definition– Bases are electron pair donators +  Donates an e- pair to the BF 3

Neutralization Reactions Stoichiometry of Acid – Base Neutralization Reactions Acid + Base  Water + A Salt (an ionic compound) Examples:

Weak Base: -Ionizes less than 100% -Lots of the unionized base will remain Example to memorize: -NH 3 (ammonia)

Strong Base: -Ionizes almost 100% Examples to memorize: -Group 1 metal hydroxides (NaOH, KOH, etc.) REMEMBER – STRONG/ WEAK DOES NOT RELATE TO DANGER LEVEL!!

Relative Strength of Acids and Bases HCl + H 2 O  H 3 O + + Cl - AcidBase Conjugate – The “leftover” after acid + base combine Conjugate Base – The left over after an ACID loses its Hydrogen ion (take a H away from the acid!) Conjugate Base Conjugate Acid – The left over after a BASE gains its Hydrogen ion (add an H to the base!) Conjugate Acid Another Example: NH 3 + H 2 O  NH OH -

Know: Strong Acids: -Hydrochloric -Sulfuric (1 st H+ only) Weak Acids: -Hydrofluoric-Acetic Relative Strength of Acids and Bases

Know: Strong Bases: -Metal hydroxides Weak Bases: -Ammonia **The stronger the acid – the weaker the conjugate base** **The stronger the base – the weaker the conjugate acid** Relative Strength of Acids and Bases Example – Which is the stronger conjugate base – acetate or chloride??

15.4 – Oxides, Hydroxides, Acids Metal oxide + Water  Base Ex – Na 2 O + H 2 O  2NaOH Nonmetal oxide + Water  Acid Ex – SO 2 + H 2 O  H 2 SO 3 SO 3 + H 2 O  H 2 SO 4

Reactions of Acids and Bases 1. Acids react with many metals to form Hydrogen gas 2. Acids react with metal oxides 3. Acids react with carbonates to form carbon dioxide gas 4. Hydroxides react with nonmetal oxides 5. Metal oxides react with nonmetal oxides