chapter23_2.ppt

CHEM 132 Layman chapter 23 Due May 3, 2010 Textbook Problems Chapter 21/# 27, 29, 33, 42, 45, 47, 53, 66, 70, 76, 84 Chapter 23/# 1, 2, 4, 6, 8, 10, 12, 18, 20, 24, 26, 33 ARIS HW #14, 14b, and 14c CHEM 132 Layman chapter 23 Next Week in CHEM 132 Final Exam (covers CHEM 131 & CHEM 132) Monday, May 3 8:00 - 10:00 AM ISAT 159 70 questions, 110 minutes CHEM 132 Layman chapter 23 Rxn. order Rate expression to integrate Integrated rate law 0 Rate = k[A]0 1 Rate =k[A] 2 Rate =k[A]2 [A]0 = initial concentration [A]t = concentration at some time t Integrated rate laws CHEM 132 Layman chapter 23 Reaction half-life how long does it take to use up half of the reactant (t1/2) [A]t = 1/2[A]0 0th order 1st order 2nd order CHEM 132 Layman chapter 23 Decay Kinetics Decay rate = activity Half-life: time it takes for 1/2 of nuclei to decay generic 1st order rxn rate = k [X] ln ([Xo]/[X]) = kt ln[Xo/(Xo/2)] = kt1/2 t1/2 = (ln 2) / k = 0.693 / k CHEM 132 Layman chapter 23 Carbon from a cypress beam obtained from the tomb of an ancient Egyptian king gave 9.2 disintegrations min-1 of 14C per gram of carbon. 14C has a half-life of 5730 years. Living organisms have an activity of 15.3 d min-1 g-1. How old is the beam? CHEM 132 Layman chapter 23 Nuclear transmutation and element synthesis t1/2 = 0.9 s t1/2 = 1400 yr t1/2 = 1.38 d t1/2 = 27 min t1/2 = 3.1 min t1/2 = 1.7 s Glenn Seaborg 1911-1999 CHEM 132 Layman chapter 23 Nuclear Fission 2.1 ? 10+10 kJ mol-1