Collision theory and Activation Energy

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Presentation transcript:

Collision theory and Activation Energy

Temperature and Activation Energy

 Temperature and  in Ea

Arrhenius Equation

Arrhenius Equation You may also come across it in a different form created by a mathematical operation on the standard one: "ln" is a form of logarithm. Don't worry about what it means. If you need to use this equation, just find the "ln" button on your calculator.

2N2O5 (g)→4NO2 (g) + O2 (g) k (s-1) T (°C) 0.000020 20 0.000073 30 0.000270 40 0.000910 50 0.002900 60

Finding Ea T (°C) T (K) 1/T (K) k (s-1) ln(k) 20 293 0.003413 0.000020 -10.82 30 303 0.0033 0.000073 -9.53 40 313 0.003195 0.000270 -8.22 50 323 0.003096 0.000910 -7.00 60 333 0.003003 0.002900 -5.84

Ea = activation energy R = 8 Ea = activation energy R = 8.314 J/mol·K T = absolute temperature in Kelvins A = frequency factor

The Arrhenius equation is often written in the logarithmic form: Bestimmung von Ea A plot of lnk versus 1/T produces a straight line with the familiar form y = -mx + b, where x = 1/T y = lnk m = - Ea/ R b = lnA The activation energy Ea can be determined from the slope m of this line: Ea = -m · R

Ea=-R(slope) Slope =Δln(k)/Δ(1/T) Ea=-(8.3145J/K*mol)(-12000K) =100,000 J/mol