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Ch. 15 - Acids & Bases. Ch. 15-1 p. 542-549 Ch. 15-2 p. 550-558. electrolytes electrolytes. Properties. ACIDS. BASES. bitter taste. sour taste. turn litmus red. turn litmus blue. react with metals to form H 2 gas. slippery feel. vinegar, milk, soda, apples, citrus fruits.
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Ch. 15 - Acids & Bases Ch. 15-1 p. 542-549 Ch. 15-2 p. 550-558
electrolytes electrolytes Properties ACIDS BASES • bitter taste • sour taste • turn litmus red • turn litmus blue • react with metals to form H2 gas • slippery feel • vinegar, milk, soda, apples, citrus fruits • ammonia, lye, antacid, baking soda ChemASAP
H H – + O O Cl Cl H H H H • Arrhenius - In aqueous solution… • Acidsform hydronium ions (H3O+) HCl+ H2O H3O+ + Cl– acid
H H – + N O O N H H H H H H H H • Arrhenius - In aqueous solution… • Bases form hydroxide ions (OH-) NH3+ H2O NH4+ + OH- base
conjugate base conjugate acid • Brønsted-Lowry • Acidsare proton (H+) donors. • Bases are proton (H+) acceptors. HCl + H2O Cl– + H3O+ acid base
Acids and bases come in pairs... • A conjugate base is the remainder of the original acid, after it donates it’s hydrogen ion • A conjugate acid is the particle formed when the original base gains a hydrogen ion
H2O + HNO3 H3O+ + NO3– B A CA CB
NH3 + H2O NH4+ + OH- B A CA CB
F - H2PO4- H2O HF H3PO4 H3O+ • Give the conjugate base for each of the following:
Br - HSO4- CO32- HBr H2SO4 HCO3- • Give the conjugate acid for each of the following:
Polyprotic Acids • Some compounds have more than 1 ionizable hydrogen. • HNO3 nitric acid - monoprotic – 1 H+ • H2SO4 sulfuric acid - diprotic - 2 H+ • H3PO4 phosphoric acid - triprotic - 3 H+ • Having more than one ionizable hydrogen does not mean stronger acid!
Not all the hydrogen in a compound may be released as ions • The hydrogen in a compound may be released as ions when the hydrogen is joined to a very electronegative element
Lewis • Acidsare electron pair acceptors. • Bases are electron pair donors. Lewis base Lewis acid
Strengths of Acids and Bases Strong acids completely ionize (100%) in aqueous solutions HCl + H2O H3O+ + Cl- (100 % ions) Strong bases completely (100%) dissociate into ions in aqueous solutions. NaOH Na+ (aq) + OH-(aq) (100 % ions)
NH3, A Bronsted-Lowry Base When NH3 reacts with water, most of the reactants remain dissolved as molecules, but a few NH3 reacts with water to form NH4+ and hydroxide ion. NH3 + H2O NH4+(aq) + OH- (aq) acceptor donor + +
Strong and Weak Acids and Bases Strong acids HCl, HNO3 ,H2SO4 Most other acids are weak. Strong bases NaOH, KOH, and Ca(OH)2 Most other bases are weak.
Learning Check Identify each of the following as a 1) strong acid or base 2) weak acid 3) weak base A. ___ HCl (aq) B. ___ NH3(aq) C. ___ NaOH (aq) D. ___ H2CO3 (aq)
Solution Identify each of the following as a 1) strong acid or base 2) weak acid 3) weak base A. _1__ HCl (aq) B. _3__ NH3(aq) C. _1__ NaOH (aq) D. _2__ H2CO3 (aq)
Antacids • Used to neutralize stomach acid (HCl) • Many contain one or more weak bases Alka-Seltzer: NaHCO3, citric acid, and aspirin Di-gel: CaCO3 and Mg(OH)2 Gelusil: Al(OH)3and Mg(OH)2 Maalox: Al(OH)3and Mg(OH)2 Mylanta: Al(OH)3 and Mg(OH)2
More Antacids Milk of Magnesia: Mg(OH)2 Rolaids: AlNa(OH)2CO3 aluminum sodium dihydroxy carbonate Tums: CaCO3 Tempo: CaCO3,Al(OH)3,Mg(OH)2