In this worksheet, we will practice using the Arrhenius equation to calculate reaction activation energies and frequency (preexponential) factors.
Q1:
When the temperature increases from to , the rate of an enzyme-catalyzed reaction increases by a factor of 1.47. Calculate to 3 significant figures the activation energy for this reaction.
Q2:
A sample of hydrogen peroxide decomposes with a rate constant of s−1 at and s−1 at . Calculate to 3 significant figures the activation energy for this reaction.
Q3:
Butene can decompose to two molecules of ethene when heated. The rate constant for the decomposition reaction at is s−1 and the activation energy is 261.0 kJ/mol. Estimate the frequency (pre-exponential) factor for the reaction, to 2 significant figures.
- A s−1
- B s−1
- C s−1
- D s−1
- E s−1
Q4:
The rate constant for a reaction, , was measured over a range of reaction temperatures, . The data were plotted on a graph of against . What is the frequency (pre-exponential) factor for the reaction in terms of the gradient of the plot and the -intercept ?
- A
- B
- C
- D
- E
Q5:
Hydrolysis of the sugar sucrose () produces glucose and fructose. This first-order reaction has a rate constant of at and at .
Calculate the activation energy for this reaction, to three significant figures.
Calculate the rate constant for this reaction at , to two significant figures.
- A s−1
- B s−1
- C s−1
- D s−1
- E s−1
Estimate, to two significant figures, the time needed for the concentration of a 0.150 M sucrose solution to decrease to M at .
- A days
- B days
- C days
- D days
- E days
Q6:
A sample of dinitrogen pentoxide decomposes with a rate constant of 1.66 L/mol⋅s at 650 K and 7.39 L/mol⋅s at 700 K. Calculate to 3 significant figures the activation energy for this reaction.