Ch. 15 Titration And pH

Ionization of Water _____________________: two water molecules produce a hydronium ion and a hydroxide ion by transfer of a proton. 15-2

Ionization of Water In a neutral solution, ________________________. Ionization constant of water = K w K w =  H 3 O +   OH -  = 1.0 x M If the  H 3 O +  = 1.0 x M, the solution is _________. ___________________________, so the hydronium concentration is greater than it would be in a neutral solution. 15-3

Example Example: A 1.0 x M solution of HNO 3 has been prepared for a lab. Calculate the  H 3 O +  and  OH -  of this solution. _________________________________  H 3 O +  = 1.0 x M _________________________  OH -  = 1.0 x M = 1.0 x M  H 3 O +  1.0 x M = 1.0 x M 15-4

Practice 1) Determine the  H 3 O +  and  OH -  of a solution that is 1.0 x M Ca(OH)

The pH Scale _____: the negative of the common logarithm of the hydronium ion concentration. ________________ = - log (1.0 x M) = 7.0 ___________________________ = - log (1.0 x M) = 7.0 pH + pOH = 14.0 ______________________________________________ 15-6

The pH Scale

Example Example: What is the pH of a solution if the  H 3 O +  is 3.4 x M? pH = -log  H 3 O +  = - log (3.4 x M) On your calculator, ______________________ Keep in mind, it is the negative of the log, so change the sign on your answer: pH = _________ 15-8

Practice 2) What is the pH of a solution if the  H 3 O +  is 2.5 x M?

pH to  H 3 O +  pH = -log  H 3 O +  log  H 3 O +  = -pH ____________________ Example: What is the  H 3 O + ,  OH -  if the pH is 7.52? Is the solution acidic or basic?  H 3 O +  = 10 -pH = ____________________________. = 3.0 x  OH -  = 1.0 x M = 1.0 x M = _______________  H 3 O +  3.0 x M pH is greater than 7.0, the solution is __________

pH to  H 3 O +  3) What is the  H 3 O + ,  OH -  if the pH is 12.0? Is the solution acidic or basic? 15-11

Indicators ___________________: compounds whose colors are sensitive to pH. _________________: the pH range over which an indicator ___________. ____________: determines the pH of a solution by measuring the voltage between two electrodes that are placed in the solution

Indicators 15-13

Titration _____________: the controlled addition and measurement of the amount of a solution of___________ ________________ required to react completely with a measured amount of a solution of unknown concentration. ___________________: the point at which the two solutions used in a titration are present in chemically equivalent amounts. ____________: the point in a titration at which an indicator changes color

Titration 15-15

Titration 15-16

Titration __________________: the solution that contains the precisely known concentration of a solute. __________________: a highly purified solid compound used to check the concentration of the known solution in a titiration

Buffers Buffered Solution: resists changes in pH with the addition of an acid or a base.

Ch. 15 The End! 15-19