This preview shows pages 1–3. Sign up to view the full content.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: CHEM 340.001–Debye–Spring 2002 NAME: ANSWERS PROBLEM SET 3 This Problem Set is given out Tuesday, April 23 at 8:00am and is due back on Tuesday, April 30 at 9:00am . You must include all work used to obtain your answers including graphs, data points generated and/or plotted, equations of lines used to fit data, etc. All work must be your own although you may collaborate with your classmates in deciding on strategies for answering the problems. ...................................................................................................................................................................... Consider the simple irreversible reaction A --> C to proceed by the following mechanism: k 1 i. A ---> B k 2 ii. B ---> C Assume that the reaction is run with [ A ] o =a o and [ C ] o =0 . The exact concentrations of the three chemical species as a function of time (t) are then given by: [ A ] = a o exp(-k 1 t ) k 1 a o exp(-k 2 t ) {exp[(k 2-k 1 ) t ] – 1} [ B ] = ------------------------------------------ k 2 – k 1 [ C ] = a o – [A] – [B] The notation is that exp[f( t )] = e f (t ) . For Problems #1 through #4 below, assume that k 1 =0.00500 s-1 , k 2 =0.00250 s-1 , and [ A ] o =0.100 moles/L 1. Using the above exact expressions, make a graph of [ B ] vs. time from the beginning of the reaction to the time when the reaction is 80% completed. Use enough points to define your graph well. Problem 1: [B] Time (in seconds) [B] 100 200 300 400 500 600 700 800 900 .0 .0 5 .0 1 .0 1 5 .0 2 .0 2 5 .0 3 .0 3 5 .0 4 .0 4 5 .0 5 .0 5 5 With an intermediate, the reaction is 80% complete based on the product formation (900 seconds, here) , and not based on the reactant disappearance (320 seconds, here). CHEM 340.001–Debye–Spring 2002 2. Again using the above exact expressions, make a graph of [ C...
View Full Document

{[ snackBarMessage ]}