Acidity Basicity and pH - acid-basechemistryunit - home酸度碱度和pH值的酸basechemistryunit回家

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,*,*,Acidity,Basicity,and pH,:/,Self-Ionization of Water,Water acts as both acid and base in same reaction,Proceeds minimally to the right,H,2,O(l)+H,2,O(l)H,3,O,+,(aq)+OH,-,(aq),Pure H,2,O,25,C,H,3,O,+,&OH,-,=1.0 x10,-7,Concentration is small but significant,K,eq,=H,3,O,+,OH,-,/H,2,O,2,Self-Ionization of Water,Pure water and dilute solutions H,2,O same-H,2,O moved to left side,K,eq,H,2,O,2,=H,3,O,+,OH,-,K,w,=H,3,O,+,OH,-,ion product constant,Pure water,25,C,K,w,=1.0 x 10,-14,K,w,=(1.0 x 10,-7,)(1.0 x 10,-7,),Applies for all water solutions at 25,C,even when H,3,O,+,OH,-,are not equal,Self-Ionization of Water,Acidic,basic and neutral solutions all contain H,3,O,+,and OH,-,Acidic H,3,O,+,10,-7,Basic OH,-,10,-7,If the concentration of H,3,O,+,in blood is 4.0 x10,-8,M,is blood acidic,basic,or neutral?What is the concentration of OH,-,ions in blood?,Self-Ionization of Water,Blood is basic,H,3,O,+,4.0 x10,-8,1.0 x10,-7,K,w,=H,3,O,+,OH,-,1.0 x10,-14,=(4.0 x10,-8,)OH,-,OH,-,=2.5x10,-7,M,Example,What is the concentration of H,3,O,+,ions in a wheat flour and water solution if OH,-,=1.0 x10,-8,M?Is wheat flour and water acidic,basic,or neutral?,1.0 x 10,-14,=H,3,O,+,(1.0 x 10,-8,M),H,3,O,+,=1.0 x 10,-6,M,Acidic,pH Scale,Based on logarithms pH=-log H,3,O,+,Numbers base 10 logarithm is its exponent when 10 is the base,log(0.001)=3 10,-3,=0.001,1 unit change in pH is 10-fold change in concentration of H,3,O,+,Sig.Figs.number of digits after decimal should equal number of sig.figs.In original number,pH,In one brand of vegetable juice,the concentration of H,3,O,+,ions is 7.3 x 10,-5,M What is the pH of the juice?,pH=-log H,3,O,+,pH=-log(7.3 x 10,-5,),Using log key=-4.13667714,pH=-(-4.13667714)=4.14,Example,In household bleach,the concentration of OH,-,ions is 5.0 x 10,-2,M.What is the pH?,1.0 x 10,-14,=H,3,O,+,(5.0 x 10,-2,),H3O+=2.0 x 10,-13,pH=-log(2.0 x 10,-13,),pH=12.70,Measuring pH,Use acid-base indicator,Indicator equation,HIn(aq)+H2O(l)H3O+(aq)+In-(aq),clearred,Add acid,shift equilibrium to left,(litmus HIn red),Add base,shift equilibrium to right,(litmus In-blue),Measuring pH,Each indicator has a different equilibrium constant,Different pH range over which color changes,Select indicator depending on pH range,