Suppose a scientist wants to modify an electroplating procedure to isolate the specific ef… — ACT

Suppose a scientist wants to modify an electroplating procedure to isolate the specific effect of temperature on the deposition rate of copper and determine the activation energy of the reaction. The scientist must ensure that concentration depletion and current fluctuations do not confound the results. Arrange the following steps in the correct chronological order to design and execute this modified follow-up experiment.

1Prepare a high-volume bath of $1.0\text{ M}$ $CuSO_4$ solution to keep the electrolyte concentration effectively constant throughout all trials.
2Perform preliminary runs to identify a stable current that avoids localized concentration polarization but yields a measurable copper mass.
3Conduct the main electroplating trials at five distinct temperatures between $15^\circ\text{C}$ and $55^\circ\text{C}$ using the selected current.
4Measure the mass of copper deposited in each trial and calculate the initial deposition rate at each temperature.
5Construct an Arrhenius plot of the natural logarithm of the deposition rate versus $1/T$ to calculate the activation energy.

Answer

The correct chronological sequence begins with preparing the high-volume electrolyte bath to maintain constant concentration. Next, preliminary trials are run to determine the optimal constant current. Once the current is established, the temperature-controlled trials are executed. After the trials, the deposited mass is measured to calculate rates. Finally, these rates are plotted against the reciprocal of absolute temperature to calculate the activation energy.

The correct sequence begins with preparing the high-volume electrolyte bath to ensure concentration remains constant. Next, preliminary trials must be run to determine the optimal current. Once the current is established, the temperature-controlled trials are executed. After completing the trials, the mass of deposited copper is measured to calculate rates. Finally, these rates are plotted to calculate activation energy.

Step-by-Step Solution

Prepare the constant concentration electrolyte bath.

Maintains a stable chemical environment.

This must be done first so that all subsequent trials, including preliminary calibration, use the same electrolyte concentration.

Run preliminary trials to select the operating current.

Determines the optimal constant current value.

A constant current must be selected prior to running the main experimental trials to properly control this variable.

Execute the temperature-controlled trials.

Generates copper deposition at different temperatures.

This step uses the selected current and prepared bath to collect raw data across the independent temperature variable.

Measure mass and calculate deposition rates.

Obtains the rate of deposition for each temperature.

The rate data is the dependent variable required for the final activation energy calculation.

Construct an Arrhenius plot.

Determines the activation energy.

This final analytical step uses the rates calculated from the trials to perform the mathematical analysis.

Key Concept

Isolating independent variables and controlling confounding factors in a multi-step sequence for follow-up experimental design.

Estimated Time:3m 0s

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