{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

# t3a - Wednesday 11:05 a.m 11:55 a.m Test#3A 3.091 Fall Term...

This preview shows pages 1–4. Sign up to view the full content.

3.091 Fall Term 2004 Test #3A Wednesday, November 17, 2004 11:05 a.m. - 11:55 a.m. Name: (please print in UPPER CASE) Recitation Instructor: A complete test consists of 4 questions. Write your answers on these pages. State your assumptions and show calculations that support your conclusions. RESOURCES PERMITTED: PERIODIC TABLE OF THE ELEMENTS, TABLE OF CONSTANTS, AN AID SHEET (ONE PAGE 8½" × 11"), AND A CALCULATOR. NO BOOKS OR OTHER NOTES ALLOWED. USE OF WIRELESS COMMUNICATIONS DEVICES STRICTLY FORBIDDEN. #1 24% #2 28% #3 28% #4 20% TOTAL 100%

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

View Full Document
3.091 Fall Term 2004 Test #3A page 2 Problem #1 (24%) log 10 (rate) catalyzed reaction slope, n = 2 intercept, k = 3.091 log 10 (concentration) The fictitious compound, pandemonium fluoride (Pd 2 F 3 ), decomposes readily at temperatures exceeding 765ºC. The figure above shows the kinetics of the reaction conducted at 800ºC. The reaction is second –1 order in concentration of Pd 2 F 3 . The value of the specific chemical rate constant, k , is 3.091 L mol –1 s . 4% (a) On the graph above, label the slope and the intercept, indicating the numerical value of each. (b) Calculate how long it takes at 800ºC for the concentration of Pd 2 F 3 to fall from 1.11 mole L –1 to 10% of that value. Express your answer in seconds. 14% (c) The same reaction is now conducted under the influence of a catalyst. On the graph above, which shows the reaction as it proceeds in the absence of a catalyst, draw the line associated with the catalyzed reaction. 6% Problem #2 (28%)
3.091 Fall Term 2004 Test #3A page 3 Composition A: 5% MgO – 95% SiO 2 ; Composition B: 20% MgO – 80% SiO 2 (a) Two glass-forming melts, A and B as specified above, are each cooled at the same rate down to room temperature. Identify which melt, A or B, exhibits the higher glass transition temperature and explain why.

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.

{[ snackBarMessage ]}