Acid/Base Chemistry Part 2 ( ) Science 10 CT05D02 Resource: Brown, Ford, Ryan, IB Chem

Topic 05 – Acids/Bases  5.1 Solutions  5.2 Definitions of Acids and Bases  5.3 Properties of Acids and Bases  5.4 Calculating pH, pOH, H+, OH-  5.5 Neutralization equations  5.6 Titrations

5.2 - Definitions of Acids and Bases  Arrhenius: Acids donate H +, Bases donate OH - ions in solution  Lowry/Bronsted: Acids donate a proton, Bases accept a proton (H + )  You will need to know each of these definitions

5.2 - Old Dudes define A/B Svante Arrhenius (Sweden) J.N. Brønsted (Denmark) Thomas Lowry (England)

5.2 - Arrhenius Definition  An acid is a material that can release a proton or hydrogen (H+) ion. Just like a salt, hydrogen chloride (HCl) in water solutions ionizes and becomes hydrogen ions (H+) and chloride ions (Cl-). HCl  H+(aq) + Cl-(aq)  A base, or alkali, is a material that can donate a hydroxide ion (OH-). Sodium hydroxide in water solutions becomes sodium ions (Na+) and hydroxide ions (OH-). NaOH  Na+(aq) + OH- (aq)

5.2 - Lowry-Brønsted Definition  An acid is a material that donates a proton.  A base is a material that can accept a proton.

5.3 - Properties of Acids and Bases  Acids (donate H +, turn litmus red, corrode active metals, neutralize bases, taste sour)  Bases (donate OH -, turn litmus blue, denature protein, neutralize acids, taste bitter  Nomenclature of simple Acids and Bases  Protonaety of Acids and Bases  There are five general properties of both acids and bases. Common properties are known beyond this but it is these five that you need to know.

5.3 - Properties of Acids For the properties of Acids and Bases, the Arrhenius definition will be used.  A1: Acids release a hydrogen ion into water (aqueous) solution.  A2: Acids neutralize bases in a neutralization reaction. An acid and a base combine to make a salt and water. The hydrogen ion of the acid and the hydroxide ion of the base unite to form water. HCl + NaOH  HOH + NaCl

5.3 - Properties of Acids  A3: Acids corrode active metals. When an acid reacts with a metal, it produces a compound with the cation of the metal and the anion of the acid and hydrogen gas.  A4: Acids turn blue litmus to red. Litmus is the oldest known pH indicator. It is red in acid and blue in base.  A5: Acids taste sour. TASTING LAB ACIDS IS NOT PERMITTED!! Stomach acid is hydrochloric acid. Citrus fruits such as lemons, grapefruit, oranges, and limes have citric acid in the juice.

5.3 - Properties of Bases  B1: Bases release a hydroxide ion into water solution.  B2: Bases neutralize acids in a neutralization reaction. HCl + NaOH  HOH + NaCl  B3: Bases denature protein. To denature a protein means to render parts of it useless most likely by unfolding it. Serious damage to flesh can be avoided by careful used of strong bases.

5.3 - Properties of Bases  B4: Bases turn red litmus to blue. This is not to say that litmus is the only acid- base indicator, but that it is likely the oldest one.  B5: Bases taste bitter. There are very few food materials that are alkaline, but those that are taste bitter. It is even more important that care be taken in tasting bases. Again, TASTING OF LAB CHEMICALS IS STRICTLY PROHIBITED. Tasting of bases is more dangerous than tasting acids due to the property of stronger bases to denature essential proteins in the body.

Nomenclature Review!!  To determine the naming system of a compound, you can simply look at the first element:  A metal = MUST BE IONIC  Does it have a polyatomic?  Does it have a transition metal?  A nonmetal = MUST BE COVALENT  Hydrogen = MUST BE AN ACID  Binary Acid?  Oxoacid (Polyatomic)?

first element Metal = Ionic  NO prefixes  The simplest whole number ratio is generally the ionic formula. (empirical formula) Binary NaCl MgBr 2 Li 2 S Polyatomic Na 2 CO 3 Mg(NO 3 ) 2 Li 3 PO 4 Transition FeCl 3 Ni 3 (PO 3 ) 2 ZrSO 4

First element nonmetal = Covalent  Greek Prefixes  Mono (1), di (2), tri (3), tetra (4), penta (5), etc….  First nonmetal keeps element name  Change ending of second nonmetal to –ide P 2 O 5 CCl 4 CO 2 COSiO 2 NO 2 CF 4 SF 6 PF 5 NO

First element hydrogen = Acid Binary H and another element Use hydro- prefix Use –ic suffix HClHFHBr H 2 SHI Oxoacid H and 2 or more NO prefix If poly –ate  -ic If poly –ite  -ous HNO 3 H 3 PO 4 H 3 PO 3 H 2 SO 4

Polyatomic Ions ( they keep coming back!) PO 4 3- PO 3 3- OH - NO 2 - NO 3 - NH 4 + SO 3 2- SO 4 2- CO 3 2- ClO 3 - ClO 2 -

5.3 – Simple Base Nomenclature  A common base is an ionic compound formed between a metal (M + ) and hydroxide (OH - ) ion.  (sodium hydroxide) NaOH  Na + + OH -  (magnesium hydroxide) Mg(OH) 2  Mg OH -  Any compound with available room to accept an H + is also considered a base  (ammonia) NH 3 + H +  NH 4 +  Covalent compounds with a hydroxide functional group, such as the alcohols (CH 3 OH, C 2 H 5 OH) are not considered to be bases

5.3 – Acid/Base Nomenclature Acid FormulaAcid NomenclatureBase FormulaBase Nomenclature H 2 SO 4 NaOH H 2 SO 3 LiOH H 2 CO 3 KOH HNO 3 RbOH HNO 2 Mg(OH) 2 H 3 PO 4 Ca(OH) 2 H 3 PO 3 Sr(OH) 2 HClO 3 NH 3 HClO 2 HCl HBr HI H2SH2S HF

5.3 – Protonaety (is that a word?)  Acids can be either monoprotic, diprotic, or triprotic where they can donate one, two, or three protons respectively  Monoprotic (HCl, HNO 3, HClO 3 )  Diprotic (H 2 S, H 2 SO 4, H 2 CO 3 )  Triprotic (H 3 P, H 3 PO 4, H 3 PO 3 )  Bases can also be considered as such because of their ability to accept protons (donate OH - )  Monoprotic (NaOH, NH 3 )  Diprotic (Mg(OH) 2, NH 2 - )

5.3 - Protonaety  Monoprotic Acid Formula:  HCl  H + + Cl -  Monoprotic Base Formula:  NH 3 + H +  NH 4 +  Diprotic Acid Formula:  H 2 SO 4  H + + HSO 4 -  2 H + + SO 4 2-  Diprotic Base Formula:  Mg(OH) 2 + 2H +  Mg(OH) + + H + + H 2 O  Mg H 2 O  Triprotic Acid Formula:  H 3 P  H + + H 2 P -  2H + + HP 2-  3H + + P 3-