For a given reaction,the activation energy is 63.9 kJ/mol.If the reaction rate constant is 4.1 × 10^-3 L/mol⋅s at 32.0°C,what is the reaction rate constant at -5.0°C? (R = 8.31 J/K⋅mol)

Question

Quizplus · Accepted Answer

We can use the Arrhenius equation to solve this problem:

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.

First, we need to convert the activation energy to Joules/mol:

63.9 kJ/mol × 1000 J/kJ = 63,900 J/mol

Then, we can plug in the given values at 32.0°C (305.2 K) to find A:

4.1 × 10^-3 L/mol⋅s = A e^(-63900 J/mol / (8.31 J/K⋅mol × 305.2 K))

A = 5.5 × 10^13 L/mol⋅s

Finally, we can use A and the given activation energy to find the rate constant at -5.0°C (268.2 K):

k = 5.5 × 10^13 L/mol⋅s × e^(-63900 J/mol / (8.31 J/K⋅mol × 268.2 K))

k = 1.3 × 10^-4 L/mol⋅s

Therefore, the answer is choice C, 1.3 × 10^-4 L/mol⋅s.

For a Given Reaction,the Activation Energy Is 63