How do I solve this Chemistry problem on activation energy?

Question

The rate constant  for the gas phase decomposition of N2O5 has the following temperature dependence 

 

T (K)       k (s^-1)

              4.9×10^-3

338.        5.0×10-4

318          3.5×10^-5

298

 

How do I make the appropriate graph using the data and determine the activation energy for the reaction?

Answer 1

You can graph the data or you can use the Arrhenius equation where ln (k₂/k₁) = -Ea/R(1/T₂ - 1/T₁) and solve for Ea.

Be sure to use K in Kelvin and R = 8.314 J/K-mole.

 

The graphical method would be to plot ln k as a function of 1/T and the slope would be equal to Ea/R, but with only 3 data points, your graph may not be the best.