North Carolina State UniversityCH CH 102, 20CH202 Postlab 11 Chemical K. WebAssign. Current Score: 25 out of 25.

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CH202 Postlab 11 Chemical Kinetics (Postlab) SCHNELL ZACHARY EUGENE CH202, section 005, Fall 2008 Instructor: weiming zheng TA WebAssign Current Score: 25 out of 25 Due: Thursday, November 20, 20... 08 11:00 PM EST Description Please complete an evaluation of your TA at Class Evaluations The link will be active from 8 am on November 21 until 8 am on December 8, 2008. If you need help, students can send a message to [email protected]. Thank you, Dr. Lori Petrovich The due date for this assignment is past. Your work can be viewed below, but no changes can be made. Important! Before you view the answer key, decide whether or not you plan to request an extension. Your Instructor may not grant you an extension if you have viewed the answer key. Request Extension View Key 1. 14/14 points Refer to Data Table B, in which you entered rate constants. In the spaces below, enter your rate constants, highest to lowest. Do not include units. Rate Constants, in M-1s-1 1.1e-05 6.0e-06 3.2e-06 0.0 0.0 a. What is the range of these values (highest - lowest)? 1.1e-05 b. What is the average of these values? 4.0e-06 The remainer of this question is designed to help you decide if the data from one of your experiments can be discarded. To quantitatively "throw out" a measurement, you must perform a statistical test on your data called a Q-Test. The formula for the Q-test is Qcalculated = gap/range CH202 Postlab 11 Chemical Kinetics http://www.webassign.net/v4cgizeschnel@ncsu/student.pl?x=200812071... 1 of 4 12/7/2008 2:46 PM where gap = (questionable value - next closest number) and range = (largest number - smallest number). Qcalculated is then compared to Qtable. If Qcalculated > Qtable then the questionable datum can be discarded. Q (90% confidnece) Number of measurements 0.76 4 0.64 5 0.56 6 c. What is the gap of these values (questionable value - next closest value)? (Take the absolute value if necessary to make this number positive.) 5.0e-06 d. What is Qcalculated for your data above? 0.45 e. Which Qtable will you compare your Qcalculated to? 0.64 f. Can the questionable value be discarded based on your Q-test results? yes no 2. 10/10 points WARNING! You will only have 3 submissions on each part of this question! In your lab write-up, three possibilities for the mechanism of the rate determining step were listed: 1. The rate-determining step has two iodide ions coming together. 2. The rate-determining step involves a persulfate ion decomposing. 3. The rate-determining step has an iodide ion and a persulfate ion coming together. Which mechanism did your experiment confirm? The third. Now consider what would have happened if one of the other mechanisms had been correct. The initial reaction is run with arbitrarily selected concentrations of reactants. Then, concentrations are varied systematically. Consider the following possibilities and select the correct outcome for each experiment. a. If the first mechanism is correct, what should happen to the rate if the concentration of iodide ion is doubled and other concentrations are held constant? The rate will double. CH202 Postlab 11 Chemical Kinetics http://www.webassign.net/v4cgizeschnel@ncsu/student.pl?x=200812071... The rate will decrease by half. The rate will not change. The rate will increase by a factor of four. b. If the first mechanism is correct, what should happen to the rate if the concentration of persulfate ion is doubled and other concentrations are held constant? The rate will double. The rate will increase by a factor of four. The rate will decrease by half. The rate will not change. c. If the second mechanism is correct, what should happen to the rate if the concentration of iodide ion is doubled and other concentrations are held constant? The rate will decrease by half. The rate will not change. The rate will increase by a factor of four. The rate will double. d. If the second mechanism is correct, what should happen to the rate if the concentration of persulfate ion is doubled and other concentrations are held constant? The rate will double. The rate will increase by a factor of four. The rate will decrease by half. The rate will not change. 3. 1/1 points You are now answering the last question of the last Postlab assignment in CH202. Which of the following words or phrases best describes your emotions at this point? YEE-HAW!!! I am SO outta here! Glory Hallelujah! Aw, nuts. All good things must end. I can't wait for my next chemistry lab course! CH202 Postlab 11 Chemical Kinetics http://www.webassign.net/v4cgizeschnel@ncsu/student.pl?x=200812071... 3 of 4 12/7/2008 2:46 PM CH202 Postlab 11 Chemical Kinetics [Show More]

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