Name ______________________________ SS# _________________________ Section _________

Instructions: Put your name, social security number, and section number on the top of this exam page. Answer the following five (5) parts in the notation and conventions of the lecture for a total of 100 points. Read the entire exam. Work alone and consult no one, living or dead, about this test (except Brucat) until after you leave the room. Notebooks, textbooks and any other study material are not allowed in the exam room. You may use only your writing and calculating instruments; sharing of calculators is NOT allowed. Show work where appropriate and write only on this exam page. Show proper units to receive credit.

Your name on this exam states the assertion: I hereby pledge that I have neither given nor received any unauthorized aid in relation to this exam

R = 0.08206 latm/molK = 8.314 J/Kmol Universal Gas Constant

Kb (water) = 0.512 K/m
Kf (water) = 1.86 K/m

Part I Consider the reaction A -> Products. Initially the concentration of A is 0.125 M. After 12 minutes the concentration of A is 0.110 M. What is the concentration of A after one hour if the reaction is first order in A?


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Under the same conditions as above, what would be the concentration of A after one hour if the reaction is second order in A?


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Part II The half life of a first-order reaction is found to drop from exactly one hour to 12.0 minutes upon a change in temperature from 10.0 oC to 50.0 oC. What is the activation energy of the reaction?


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What is the half life of this reaction at 0.00 oC?


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Part IIIa The freezing point of a dilute solution of sucrose in water is found to be 272.00K. What is this solutions' normal boiling point?


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Part IIIb The Osmotic pressure of a given system is found to be 0.0100 atm at 0.00 oC.. At what temperature is the osmotic pressure of the same system 0.0120 atm if all other conditions are held constant?


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Part IV Consider the following reaction:

2A + 3B + C -> D

Initial rate as a function of initial concentration data for this reaction is compiled in the following table:
[A]0, M [B]0, M [C]0, M Initial rate, M/s
2.76 0.62 1.12 1.66 x 103
1.52 1.52 2.24 2.20 x 104
2.76 0.97 1.12 4.07 x 103
1.52 0.25 1.12 1.49 x 102

Show your Work:




The order of the reaction in A is ___________________

The order of the reaction in B is ___________________

The order of the reaction in C is ___________________

The rate constant for the reaction is ________________

Part V The time dependence of the chemical reaction
A -> Products
is studied by monitoring the depletion of the reactant at various times.
The following data is obtained:

time, minutes [A], M
0.00 1.000
12.0 0.698
20.0 0.549
35.0 0.350
50.0 0.223

Prove that the reaction is first order in A. Show Your Work:



The half life of the above reaction is ____________________

PJ Brucat // 7/21/98 // University of Florida