Electroplating

Recommended for grades 9–12.

Figure from experiment 21 from Advanced Chemistry with Vernier

Introduction

In this experiment, you will conduct, observe, and measure the process of electroplating. This process is used to deposit a layer of metal, such as chromium, copper, or gold, onto another metal. As a commercial process, electroplated coatings are used to improve appearance, resist corrosion, or improve hardness of metallic surfaces. This experiment describes one method of producing a copper coating on a brass key or other suitable metallic object.

You will prepare an electrochemical cell by using a copper strip as the cathode (positive terminal) and a brass key as the anode (negative terminal). The electrodes are immersed in a solution containing acidified copper (II) sulfate. As you apply a potential to the electrodes, you will be effectively transferring Cu atoms from the anode to the surface of the brass key.

In this experiment, you will use one application of Faraday’s law, stated in equation form below.

${\text{Mass deposited at an electrode}} = \frac{{I \times t \times (MM)}} {{96,500 \times n}}$

I is the current in amperes; t is the time that the current is applied, in seconds; MM is the molar mass of the element that is deposited; n is the number of moles of electrons/mol; and 96,500 is ₣, the Faraday constant.

Objectives

In this experiment, you will

Prepare and operate an electrochemical cell to plate copper onto a brass surface.
Measure the amount of copper that was deposited in the electroplating process.
Calculate the amount of energy used to complete the electroplating process.

Sensors and Equipment

This experiment requires each of the following Vernier sensors and equipment (unless otherwise noted):

Current Probe

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

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The student-version preview includes:

Step-by-step instructions for computer-based data collection
List of materials and equipment

Note: The experiment preview of the computer edition does not include essential teacher information, safety tips, or sample data. Instructions for Logger Pro and other software (such as LabQuest App or TI handheld software, where available) are on the CD that accompanies the book. We strongly recommend that you purchase the book before performing experiments.

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