Collision theory and Activation Energy
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The highlights are:
1. Temperature and Activation Energy
2. Arrhenius Equation
3. Finding Ea
4. Ea = -R
1.
Collision theory and
Activation Energy
4.
Temperature and Activation Energy
5.
Temperature and in Ea
7.
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.
8.
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
9.
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
10.
Ea = activation energy
R = 8.314 J/mol·K
T = absolute temperature in
Kelvins
A = frequency factor
11.
The Arrhenius equation is often written in the logarithmic form:
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
Bestimmung von Ea the slope m of this line: Ea = -m · R
12.
Slope =-Ea/R
0.00
0.0029 0.003 0.0031 0.0032 0.0033 0.0034 0.0035
-2.00
-4.00
ln (k)
-6.00
-8.00
-10.00
-12.00
1/T (K)
13.
Ea=-R(slope)
• Slope =Δln(k)/Δ(1/T)
• Ea=-(8.3145J/K*mol)(-12000K)
• =100,000 J/mol
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