12.9 - Last reminders: This week (Dead Week) is your last...

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Last reminders: This week (Dead Week) is your last chance at: SI Office hours Most semester exam, homework and extra-credit grade issues If there are grade issues on Exam 4, I am willing to address those issues until 2:30 PM on Monday, April 27. Last reminders: Final exam time scheduled by university: CH101-002 (MWF 11:20 12:10) Monday, May 4, 8-11 AM DAB222 Per university regulation, students must take their final exam during the section they are REGISTERED for. The only reason for an exam time change is three exams in 24 hours. pH and pKa pH: -log [H 3 O 1+ ] pK a : -log [K a ] Section 12.9 Acid Dissociation Constant HA (aq) + H 2 O (l) A 1- (aq) + H 3 O 1+ (aq) K = The stronger the acid the more the product side is favored, i.e., the bigger the K a , the larger the [H 3 O 1+ ], and the smaller the pK a [A 1- ][H 3 O 1+ ] [HA] a pH and pKa pH: -log [H 3 O 1+ ] pK a : -log [K a ] A variable quantity: HIGHLY dependent upon both concentration and the strength of the acid/ base used. A fixed quantity: Inherent to the acid/ base used. Section 12.9 In base 10, the log is simply the exponent. pH = -log [H 3 O 1+ ] What is log? -log 10 -3 = ___ 3 Section 12.9 -log(0.0001) = -log(1 x 10 -4 ) = 4 on a TI=83+, type in “( - )” “LOG” “1” “2 nd ” “EE” “( - )” “4” -log(0.0025) = -log(2.5 x 10 -3 ) = 2.60 on a TI=83+, type in “( - )” “LOG” “2.5” “2 nd ” “EE” “( - )” “3” What is the pH when [H 3 O 1+ ] = 0.000001? 1. 6
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This note was uploaded on 03/30/2010 for the course CH 101 taught by Professor Bigham during the Fall '08 term at N.C. State.

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12.9 - Last reminders: This week (Dead Week) is your last...

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