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posted by  Jbroncos06balla on 1/22/2008 7:18:58 PM  |  status: Closed  

Please Help! Will Give Lifesaver! - Determining Activation Energy

Course Textbook Chapter Problem
General Chemistry N/A N/A N/A
Question Details:
Could someone please show me how to do this problem?  Please show all work/steps.
The second-order rate constant for the decomposition of nitrous oxide (N2O) into nitrogen molecule and oxygen atom has been measured at different temperatures given below.

k(1/M·s) t(°C)
1.87 10-3 600
0.0113 650
0.0569 700
0.244 750

Determine graphically the activation energy for the reaction.
kJ/mol
 
*Hint!:
  • Remember to plot 1/T on x-axis (horizontal) and ln k on y-axis (vertical). Also remember to convert the temperature to Kelvin. Then the slope is equal to -Ea/R. Watch your units!
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    Apprentice
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    posted by nimmy on 1/22/2008 8:10:47 PM  |  status: Live
    Asker's Rating: Lifesaver   
    Jbroncos06balla's comment:
    "Thank you very much!"
    Response Details:
    When you solve this you want to graph the y coordinate  as ln k and the x coordinate as 1/T (in K)
     
    The slope of the line of the graph = -Ea/R
     
    Take two pairs of coordinates and find the slope using slope formula or by using the LinReg (ax+b) function of your calculator
     
    Then have slope= -Ea/R
     
    multipy slope by negative R (-8.314) to find the value of your activation energy
     
    your answer will be in Joules/mol
     
    * using my calculator I found the slope of the line to be -29005.8311
     
    If you multiply that by -8.314 you get an activation energy of
     
    241154.4798
     
    with significant digits in mind that would be
     
    241000 J as your activation energy
     
    which equals 241 kJ/mol as your activation energy
     
    Please rate my answer
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