home > q&a board > chemistry > topic: activation energy

Q BgQuestion:

Scholar
Karma Points: 234
Respect (95%):
posted by  caribbeankahakai on 9/17/2008 7:08:47 PM  |  status: Live  

Activation Energy

Course Textbook Chapter Problem
General Chemistry N/A N/A N/A
Question Details:
I'm confused on how to go about this problem...any ideas? Thanks so much!!

The activation energy of a certain reaction is 67.2 {\rm kJ/mol}. 
How many times faster will the reaction occur at 51^\circ {\rm C} than at 0 ^\circ {\rm C}?
Bonus Point Alert! Earn +4 additional karma points for helping this annual member.

AAnswers:

Answer Question
(Cramster SME)
Moderator
posted by Werner on 9/18/2008 5:43:08 AM  |  status: Live
Asker's Rating: Lifesaver   
caribbeankahakai's comment:
"awesome, thank you"
Response Details:
  Given that
    T1 = 00C
        = 273 K
   T2 = 51 0C
        = 324 K
   k2 /k1 = ?
   Ea = 67.2 kJ/mol
        = 67200 J/mol
   Accrding to Arrhenius equation
      ln(k2/k1) = (Ea/R){(1/T1) -(1/T2)}
    ln(k2/k1)   =  (Ea/R){(1/T1) -(1/T2)}
                    = (67200 J/mol / 8.314 J/K.mol ) { (1/273K) - (1/324K) }
                    = 4.66
         (k2/k1) = e4.66
                     = 105.64
   Hence the reaction is 105.64 times faster at 51^\circ {\rm C} than at 0 ^\circ {\rm C}.
Guru
Karma Points: 2,028
(V.T.College)
posted by Ainala8055 on 9/18/2008 6:24:44 AM  |  status: Live
Asker's Rating: Helpful   
caribbeankahakai's comment:
"thanks!"
Response Details:
Activation energy    Ea = 67200 J/mol
   Accrding to Arrhenius equation
      ln(k2/k1) = (Ea/R)(t2-t1/t1t2)
    ln(k2/k1)   =  (67200 J/mol / 8.314 J/K.mol ) (51/273 x 324) 
                    = 4.66
         (k2/k1) = e4.66
                     = 105.64
                 k2=105.64k1
Answer Question
Ask New Question

Join Cramster's Community

Cramster.com brings together students, educators and subject enthusiasts in an online study community. With around-the-clock expert help and a community of over 100,000 knowledgeable members, you can find the help you need, whenever you need it. Join for free today » How Cramster is different from tutoring »

Need Help In

Useful Links