Chapter 15 Acid Base Titration and pH XavierHigh School15章酸碱滴定和pH值沙维尔高中.pptVIP

Chapter 15: Acid-Base Titration and pH 1. What ions are associated with acids? Bases? What mathematical operation is the pH scale based on? What is the pH scale? How does it “work”? Give the 3 ways to classify acids and bases. The pH Scale Weak acids Hydronium (H3O+) and Hydroxide (OH-) ions… … produced by acids and bases in solutions Also produced by self-ionization of water, where 2 molecules of water produce H3O+ and OH- by moving a proton: H20(l) + H20(l) H30+(aq) + OH-(aq) Water is a weak electrolyte What does that mean? Measurements show that molar [H30+] and [OH-] = 1.0 x 10-7 mol/L Product of [H30+] and [OH-] is always constant called the Ionization constant of H20: Kw = [H30+] [OH-] = (1.0 x 10-7)(1.0 x 10-7) = 1.0 x 10-14 (@ 25°C) The Formula Ionization constant of H20: Kw = [H30+] [OH-] Kw = the ionization constant of water [H30+] = concentration of hydronium [OH-] = concentration of hydroxide As temperature increases… The ionization of water increases - explain… What about when we start to manipulate their concentrations? Explain mathematically, as well… Calculating Concentrations of these ions If we know the concentration of one ion, along with Kw, we can determine the concentration of the missing ion Let’s review the example on p. 501 With a partner, complete the 1-3 practice problems on p. 502 in your notebook - we will reconvene in about 5 minutes (remember, strong acids and bases completely ionize!). Try #4 on your own! pH Scale Revisited French for “hydrogen power” Indicates [H30+] pH = -log [H30+]; since this is based on the power of 10, 1.0 x 10-7 H30+ = pH of 7 (neutral) Likewise, pOH = -log [OH-]; 1.0 x 10-7 0H- has a pOH of Sum of pH and pOh always equals 14, thus: pH + pOH = 14 Review example on p. 504 and 505 together Complete PP on p. 505 w/ partner (5 min.) Do Now Take Quiz – 20 min. Group work with partner (to be turned in): PP 8, 9, 11, 14 on p. 523 * Strong acids Weak bases Strong bases T