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Acids & Bases. pHun pH Notes!. pH Scale…. Acids pH < 7 sour conduct electricity react with metals to form H 2 gas turn litmus paper pink. Bases pH > 7 bitter conduct electricity feel slippery turn litmus paper blue. Properties of…. Video Quizlet. Arrhenius Model
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Acids & Bases pHun pH Notes!
Acids pH < 7 sour conduct electricity react with metals to form H2 gas turn litmus paper pink Bases pH > 7 bitter conduct electricity feel slippery turn litmus paper blue Properties of…
Arrhenius Model Acids produce H+ or H3O+ in aqueous solutions Bases produce OH- in aqueous solutions Bronsted-Lowry Model Acids are H+ ion (a.k.a. proton) donors Bases are H+ ion acceptors Two Definitions
sToP & tHinK • Example: HBr <--> H+ + Br- • acidic or basic? • what is the pH range for HBr? • Example: KOH <--> K+ + OH- • acidic or basic? • what is the pH range for KOH?
Bronsted-Lowry Model Acids donate H+ ions Bases accept H+ ions • Acids and bases exist as ‘conjugate pairs’ for a reaction • Acid paired w/ conjugate base • conjugate base accepts the H+ ion • Base paired w/ conjugate acid • conjugate acid donates the H+ ion
conjugate acid-base pair: the acid on one side and the base it forms on the other side.
sToP & tHinK In the following reaction identify the conjugate acid-base pairs. HBr + H2O --> H3O+ + Br-
Strong vs. Weak Acids • Strong acids completely dissociate • one way arrow • HCl --> H+ + Cl- • Weak acids are in equilibrium - H+ is not totally ionized • equilibrium arrow • HC2H3O2 <--> H+ + C2H3O2- • Either one can be dilute or concentrated…
Monoprotic vs. Polyprotic • Monoprotic - acids that donate one H+ • HCl • Polyprotic - acids that can donate more than one H+ • H2SO4
Acid Base Neutralization • Acid-base neutralization: a reaction between an acid and base that results in a salt and water. • Identify the salt… Ca(OH)2 + 2HF <--> CaF2 + 2H2O
pH scale is logarithmic - pH 5 has 10 x more H+ than pH 6, and so on…
Kw - ion product constant for water H2O (l) <--> H+ (aq) + OH- (aq) Kw = [H+][OH-]= 1.0x 10-14 ALWAYS!!!
sToP & tHinK • If the hydrogen ion concentration in an aqueous solution is 1.0 x 10-3 M, what is the hydroxide ion concentration? • Is this solution acidic or basic?
pH, pOH • pH - measure of H+ ions pH = -log[H+] • pOH - measure of OH- ions pOH = -log[OH-] • pH + pOH = 14
sToP & tHinK If the concentration of hydrogen ions in a solution is 1.0 x 10-9M… What is the pH? What is the pOH?
sToP & tHinK If the concentration of hydrogen ions in a solution is 1.0 x 10-4M… What is the pH? What is the pOH? What is the [OH-]?
Learn the following definitions from labs & reading… • neutralization reaction • acid-base indicator • titration • end point