Name:
AP Chemistry
Date:
Period:
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Drill – Temperature! Graphs! Rates!
1. The gas reaction
N2O5 → 2NO2 + 1/2O2
Follows the Arrhenius equation k = Ae
where R = 8.314J K-1mol-1 and 1 calorie = 4.184J. At the
-5 -1
temperature T=273 K, k = 3.46 x 10 s , whereas at T = 298K, k = 8.87 x 10-3 s-1.
a. What is the value of the activation energy Ea in kcal/mol
(-Ea/RT)
2. The rate constant, k, was determined for the decomposition of hydrogen iodide at various temperatures. The
results giving in k for a range of temperatures are given below.
Temperature (K)
ln k
550
-15.6
600
-12.2
650
-9.4
700
-7
750
-4.9
a. Plot a graph of ln k against T-1. (Take the ln k axis from – 20 to 0 and the T-1 axis from 1.2 x 10-3 to
1.9 x 10-3 K-1)
b. Calculate the slope of your graph and use it to determine a value for the activation energy.
c. Without obtaining the actual value, state two different ways in which the value of A in the Arrhenius
question could be determined.
Name:
Empower Yourself
AP Chemistry
Empower Your Community
Date:
Empower Your World
Period:
3. The rate constants for the decomposition of ethanol:
CH3CHO  CH4 + CO
Were measured at five different temperature, the data are shown in the table below:
Temperature (K)
k (M-1s-1)
700
0.011
730
0.035
760
0.105
790
0.343
810
0.789
Plot ln k verses 1/T and determine Ea for the above reaction
4. Draw the graphs for Zero, First, and Second Order reactions and explain how these can help you determine
the rate constant for the reaction of interest