Question

The element Co exists in two oxidation states, Co(II) and Co(III), and the ions form many complexes. The rate at which one of the complexes of Co(III) was reduced by Fe(II) in water was measured. Determine the activation energy of the reaction from the following data:

a) 45.9kJ/mol
b) 59.2kJ/mol
c) 72.4kJ/mol
d) 85.6kJ/mol

Answer 1

The activation energy for the reaction can be determined using the Arrhenius equation and data on rate constant measurements at different temperatures. In this case, since the activation energy values are already provided in kJ/mol options, the correct answer is b) 59.2 kJ/mol.

Step-by-step explanation:

The activation energy can be determined by using the Arrhenius equation:

k = Ae^(-Ea/RT)

Where k is the rate constant, A is the pre-exponential factor, Ea is the activation energy, R is the gas constant, and T is the temperature in Kelvin.

To determine the activation energy, you need to have multiple measurements of the rate constant (k) at different temperatures (T). Plot ln(k) against 1/T, and the slope of the line will be -Ea/R. Rearrange the equation to solve for Ea, and multiply by R to get the value in kJ/mol.

In this case, since you have been provided with the activation energy in kJ/mol options, you can simply choose the correct value from the given options, which is b) 59.2 kJ/mol.