Chemistry 104 A/D Discussion: Lecture #16 - Rate Laws, Half Life, Pseudo Order Reactions -, Exams of Chemistry

Download Chemistry 104 A/D Discussion: Lecture #16 - Rate Laws, Half Life, Pseudo Order Reactions - and more Exams Chemistry in PDF only on Docsity! Chemistry 104 A/D Discussion Section Worksheet Discussion Section #16 Key Ideas from Lecture #16: Integrated rate laws Half life Pseudo order reactions Let’s think about these concepts for a bit... Why should we use a second order integrated rate law to determine the change in concentration over time for a reaction where a plot of 1/[reactant] vs time is a straight line? (the answer, “because it is second order” isn’t good enough.) Problems: Spring 2007, Exam #2, Problem 9 9. You are studying the reaction A B + C in your lab and you have performed an experiment that allows you to look at [A] at different times. You plotted the data using the integrated rate laws for zero, first, and second order processes. You found that a plot of 1/[A] (M-1) vs time (seconds) gave a straight line with a slope of 0.032. If you started with a 0.500 M solution of A, how long will it take for the concentration of A to decrease to 0.00100 M? Spring 2007, Exam #2, Problem 10 10. For the reaction A products, successive half-lives are observed to be 6.0, 12., and 24. minutes for an experiment in which [A]o = 0.20 M. Calculate the concentration of A at 77. minutes. Spring 2007, Exam #2, Problem 15 15. Consider the reaction: 3A + B C + D Where the rate law is defined as [ ] [ ] [ ]BAk t A 2= Δ Δ− . A reaction was performed where [B]o = 0.500 M and [A]o = 5.00 x 10-5 M. After 3.00 min, [A] = 2.3 x 10-5 M. What is the value of the rate constant k? 1