Celdas Galvánicas
At the end of this lab, students should know...
What is electrochemistry?
Electrochemistry is a branch of chemistry that studies the relationship between a chemical reaction and electrical energy.
What are the key components of an electrochemical cell?
An electrochemical cell consists of a reaction chamber (or chambers) containing electrolyte solution(s), a salt bridge, and two conductive electrodes (the anode and cathode) that are connected electrically...
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Glass funnel10
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10-mL graduated cylinder5
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50-mL graduated cylinder5
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100-mL glass beaker15
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600-mL glass beaker5
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100-mL volumetric flask5
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20-mL volumetric flask5
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2-mL pipette controller5
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1-mL volumetric pipette5
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6-well reaction plate5
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Glass thermometer5
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Alligator clips10
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Glass stirring rod5
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Multimeter & leads5
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Forceps5
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2" string soaked in KNO315
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1 x 9 inch filter paper strips10
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1 x 2 inch emery paper strips10
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1 x 9 cm copper strips10
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2 x 6 cm lead strips10
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2 x 6 cm zinc strips10
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2 x 6 cm silver strips10
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Pb(NO3)2 (minimum 0.35 g per group)5 g
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CuSO4·5H2O (minimum 1.2 g per group)10 g
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C2H2O4·2H2O10 g
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KNO34 g
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ZnSO4·7H2O5 g
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AgNO310 mL
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250-mL glass graduated cylinder1
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500-mL glass graduated cylinder1
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250-mL Erlenmeyer flask3
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500-mL Erlenmeyer flask1
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250-mL glass bottle with cap1
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Powder funnel1
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125-mL brown glass bottle with cap4
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500-mL polyethylene bottle with cap1
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Magnetic stir bar4
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Stir plate1
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Top-loading balance1
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Weighing boats-1 Dependent on lab size
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Spatula-1 Dependent on lab size
Source: Smaa Koraym at Johns Hopkins University, MD, USA
- Preparation of Solutions
Here, we show the laboratory preparation for 10 students working in pairs, with some excess. Please adjust quantities as needed.
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To set up for this lab experiment, wear the appropriate personal protective equipment, including a lab coat, chemical splash goggles, and gloves
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Prepare 0.1 M oxalic acid dihydrate. Each group will need 50 mL. For 500 mL of solution, weigh 6.304 g of oxalic acid, and transfer it to an Erlenmeyer flask. Note: Oxalic acid is corrosive, so use caution while handling.
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Measure 500 mL of deionized water, and pour it into the flask. Add a stir bar and set the flask onto a stir plate. Turn on the stir setting and allow the solution to mix until it is homogeneous.
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Obtain a polyethylene bottle with a cap and label it. Use a powder funnel to transfer the solution to the bottle, cap it, and store it in the instructor's hood until the lab.
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Prepare a 0.1 M potassium nitrate solution, which will be used to soak the strings for the salt bridge. To make 250 mL of solution, weigh 2.53 g of potassium nitrate and transfer it to a flask.
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Add 250 mL of deionized water to the flask and stir the solution until it appears homogeneous.
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Transfer the solution into a labeled glass bottle and store it in the instructor's hood until the lab class.
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Prepare a 0.05 M zinc sulfate solution, which will be used as an unknown solution in the experiment. Each group will need 8 mL of solution, so calculate how much you will need to make for your class.
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To make 250 mL of solution, weigh 3.6 g of zinc sulfate and transfer it to an Erlenmeyer flask.
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Add 250 mL of deionized water to the flask and set the solution on the stir plate to mix.
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Once the solution appears homogeneous, divide it into two brown glass bottles.
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Label one of the bottles as ‘unknown number 1’, and the other as ‘unknown number 3’. Store the bottles in the instructor's hood until the lab.
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Prepare 0.22 M silver nitrate, which will also be used as an unknown solution in the experiment. Each group will need 8 mL. To prepare 250 mL of solution, weigh 9.34 g of silver nitrate, and transfer it to the flask.
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Add 250 mL of deionized water and mix the solution until it is homogeneous.
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Then, transfer the solution to two brown glass bottles. Label them ‘unknown number 2’ and ‘unknown number 4’. Store the bottles with the other prepared solutions in the instructor's hood.
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- Preparation of Other Reagents
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Each group will need about 1.25 g of copper sulfate. Place the bottle next to the analytical balance along with a clean spatula and weigh boats.
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Each group will need about 0.35 g of lead nitrate. Place the bottle next to a balance.
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You'll also need 1 x 9 cm pieces of copper sheet. Count out enough for each group to have two pieces and place them in a container.
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Each group will also need one piece of lead. Obtain 2 x 6 cm pieces of lead and put them in a labeled beaker.
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Obtain 2 x 6 cm pre-cut pieces of zinc sheet, one for each group. Divide the strips into two beakers with one labeled as unknown number 1 and the other as unknown number 3.
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Each group will also need one 2 x 6 in piece of silver sheet. Divide the strips into two beakers with one labeled as ‘unknown number 2’, and the other as ‘unknown number 4’.
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Cut emery paper in 1 x 2 in pieces so that each group has two pieces.
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Cut filter paper into 1 x 9 in pieces with one for each group.
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Cut pieces of string 2 in long. Each group will need three pieces of string, so cut as many as are needed for the class size.
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An hour before the lab class begins, place the pieces of string in the bottle of potassium nitrate and allow them to soak.
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Ensure that a 20-L container is dedicated to heavy metal waste and is accessible for all students in the hood.
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Set out the remaining equipment and glassware at each lab station (we suggest that students work in pairs):
1Multimeter with red and black leads 2Alligator clips 1Glass thermometer 16-well reaction plate 1Pair of forceps 120-mL volumetric flask 1100-mL volumetric flask 11-mL volumetric pipette 12-mL capacity pipettor 3100-mL beakers 110-mL graduated cylinder 150-mL graduated cylinder 1600-mL beaker 2Glass funnels
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View the full transcript and gain access to JoVE Lab Manual videos
Q1: How do you prepare a 0.1 M oxalic acid solution for a galvanic cells lab?
Weigh 6.304 g of oxalic acid dihydrate and transfer it to an Erlenmeyer flask. Add 500 mL of deionized water, then stir until homogeneous. Use a powder funnel to transfer the solution to a labeled polyethylene bottle and store it in the instructor's hood. Handle oxalic acid with caution as it is corrosive.
Q2: What materials are needed to prepare a salt bridge for a galvanic cell experiment?
Cut string into 2-inch pieces, with three pieces needed per group. Soak the strings in a 0.1 M potassium nitrate solution for one hour before the lab begins. This prepares the salt bridge, which maintains electrical neutrality between the two half-cells in the galvanic cell.
Q3: How should metal electrodes be prepared before use in a galvanic cells experiment?
Cut copper sheet into 2 x 9 cm pieces, zinc sheet into 2 x 6 cm pieces, and silver sheet into 2 x 6 cm pieces. Store each metal type in labeled beakers corresponding to unknown numbers. Clean metal surfaces with emery paper cut into 1 x 2 inch pieces to remove oxidation before assembly.
Q4: What is the correct procedure for preparing unknown solutions in a galvanic cells lab?
Prepare 0.05 M zinc sulfate by weighing 3.6 g and dissolving in 250 mL deionized water. Prepare 0.22 M silver nitrate by weighing 9.34 g and dissolving in 250 mL deionized water. Divide each solution into two brown glass bottles labeled with corresponding unknown numbers and store in the instructor's hood.
Q5: What equipment should be set up at each lab station for a galvanic cells experiment?
Each station requires a multimeter with leads, alligator clips, glass thermometer, 6-well reaction plate, forceps, volumetric flasks, graduated cylinders, beakers, glass funnels, and a 20-mL volumetric flask. These tools enable students to measure solutions, monitor voltage, and assemble electrochemical cells for data collection.
Q6: How do you prepare the potassium nitrate solution for the salt bridge?
Weigh 2.53 g of potassium nitrate and transfer to a flask. Add 250 mL of deionized water and stir until homogeneous. Transfer the 0.1 M solution to a labeled glass bottle and store in the instructor's hood. Use this solution to soak salt bridge strings one hour before the lab.
Q7: What safety and waste management procedures are required for a galvanic cells lab?
Wear appropriate personal protective equipment including a lab coat, chemical splash goggles, and gloves. Handle oxalic acid with caution as it is corrosive. Dedicate a 20-L container for heavy metal waste and ensure it is accessible in the hood for safe disposal of all metal-containing solutions and materials.