The following is an Arrhenius plot of a first-order reaction. The rate constant is measured in units of s^-1. Based on this Arrhenius plot, what is the activation energy of the reaction? (R = 8.314 J/K •mol)

Question

Quizplus · Accepted Answer

The activation energy can be determined from the slope of the Arrhenius plot, which can be calculated as:
slope = -Ea/R
where Ea is the activation energy and R is the gas constant (8.314 J/K•mol). From the plot, we can see that the slope is approximately -5000 K, therefore:
5000 = Ea / (8.314)
Ea = 5000 x 8.314 = 41.57 kJ/mol (rounded to 42 kJ/mol) 
Therefore, choice D (42 kJ/mol) is the correct answer.

The Following Is an Arrhenius Plot of a First-Order Reaction