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Two Hands-On Electrochemistry Experiments: Avogadro’s Number and the Electrochemical Series

Electrochemistry, from redox reactions to galvanic cells, is one of the most challenging topics for high school and first-year college chemistry students. However, one way to make it more accessible is to show students that the constants and reference tables in textbooks aren’t arbitrary facts. Instead, they’re values that can be verified through hands-on experimentation! 

The two experiments in this blog post use a green chemistry approach and cover key concepts in electrochemistry relevant to both general and advanced courses. Students are asked to investigate two standard references—the mole (Avogadro’s number) and the electrochemical series—and conduct hands-on experiments to understand how these references were established. These investigations not only prompt students to think critically about where scientific knowledge comes from but also highlight real-world chemistry applications in sustainable design.

How Electrochemistry Plays a Key Role in a Sustainable Future

Electrochemistry plays a key role in the design and optimization of technologies that support a sustainable future, from the batteries powering smartphones and electric cars to electrolyzers producing carbon-free hydrogen. The electrochemical properties of materials, such as metals, guide engineers in selecting components that contribute to eco-friendly outcomes. By understanding these key processes, students gain insight into the environmental impacts of different materials and discover how informed design choices drive more sustainable and efficient technologies.

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What can the electrochemical series teach us about the spike in catalytic converter theft? This short video uses a real⁠-⁠world example to illustrate how eco-friendly engineering design is not only shaped by atomic properties and chemical reactions but also by factors like cost and resource scarcity.

1. Determining Avogadro’s Number

Experiment #31 from Advanced Chemistry with Vernier

Download the green chemistry version here!

For many students, the concept of counting something so small that it can’t be seen with the naked eye—like the number of atoms in a drop of water or a grain of salt—can feel overwhelming. The mole unit is essential in chemistry, but its enormous scale and seemingly arbitrary value often confuse students. How exactly do we determine such a massive number? Is it something that can only be known through theory, or can it be measured experimentally? Why is it SO big?

Avogadro’s number, the number of atoms in 12 grams of carbon-12, is widely accepted to be 6.022 × 10²³, but this wasn’t always common knowledge. Avogadro himself pioneered the idea in the nineteenth century through experiments such as electrolysis, a technique still used today to explore the fundamental properties of atoms and molecules.

What You’ll Need

What Students Will Do

In this experiment, students determine Avogadro’s number for themselves using electrolysis. In electrolysis, an external power supply drives an otherwise nonspontaneous reaction in the electrolytic cell. Students use a copper strip as the anode and a zinc strip as the cathode, placed in a beaker containing sulfuric acid or a more sustainable alternative, such as Epsom salts (MgSO4).

Using the Go Direct Constant Current System, clip the zinc strip to the black (negative) lead and the copper strip to the red (positive) lead before carefully placing the electrodes in the solution.

By determining the average current used in the reaction, along with the knowledge that all of the copper ions formed are the 2+ cations, students calculate the number of atoms in one mole of oxidized copper metal and compare this value with Avogadro’s number. This hands-on experiment allows students to confirm that the mole is not just a theoretical value but a measurable constant—and gives them tools to see into the hidden world of atoms.

Use the Statistics tool in Graphical Analysis to determine the average current of collected data. In Graphical Analysis Pro, students can use the Notes feature to add notes and show their thinking.

How It Supports 3D Standards

This experiment builds on student knowledge of matter and its interactions and engages students in mathematical and computational thinking to communicate the proportional relationships between masses of atoms in the reactants and the products

Tips

  • An analytical balance is required to measure the small change in mass of the copper electrode.
  • For a green chemistry approach, opt for using Epsom salts! You can prepare 1 M MgSO4 from store-bought Epsom salt, MgSO4•7H2O, by dissolving 246.5 g of hydrated salt in enough distilled water to make 1 L of solution.
  • To continue the green chemistry focus, ask students why we might use Epsom salts in place of sulfuric acid. How do safer chemicals impact the precision of scientific experiments? Can we achieve the same level of accuracy while using more eco-friendly materials?

2. Green Chemistry and the Electrochemical Series

Download the free experiment here

The world is in a race to find sustainable energy solutions that can reduce our reliance on fossil fuels and minimize environmental impact. Electrochemical reactions play a critical role in these efforts, powering technologies such as fuel cells, solar cells, and rechargeable batteries. Have you ever wondered how a solar panel converts sunlight into usable energy or why electric vehicles rely on lithium-ion batteries for their efficiency and longevity?

At the heart of these innovations lies the electrochemical series, a ranking of how easily different metals and their ions either gain or lose electrons. This series helps students understand how energy can be efficiently stored and released in devices like batteries and fuel cells. But which metals are best suited for sustainable energy technologies? Why do some materials lead to better energy storage or longer-lasting devices than others? How can we select materials that are not only efficient but also sustainable and environmentally friendly?

What You’ll Need

What Students Will Do

In this experiment, students explore the electrochemical series by constructing electrochemical cells and measuring their voltages in the half-cell plate. Students record the reactivity of different metals and rank them based on their tendencies to gain or lose electrons. This ranking help students understand why certain materials are chosen for energy storage devices like batteries and why some metals are preferred in technologies like hydrogen fuel cell.

Electrochemistry Half-Cell Plate in an electrochemistry experiment setup
Using the Electrochemistry Half-Cell Plate and Go Direct Voltage Probe, attach the red (positive) lead to the metal strip acting as the cathode and the black (negative) lead to the metal strip acting as the anode.

More importantly, as students explore the electrochemical series, they also begin to consider the environmental impact of our choices. Can we select metals and processes that minimize waste, use less toxic materials, and align with the principles of green chemistry? In the context of sustainable energy, these choices matter, and students will be challenged to think about how materials can be used more responsibly in energy technologies.

Each half-cell voltage differential is collected in “Events with Entry” mode in Vernier Graphical Analysis. In the Pro version, features like bar graphs and text-based event entry (shown above) can make data tracking even easier.

How It Supports 3D Standards

This experiment builds on students’ knowledge of matter and its interactions and develops mathematical and computational thinking skills. It also encourages students to analyze data in the context of complex real-world problems and evaluate solutions based on criteria like cost, safety, and reliability.  

Tips

  • We recommend starting with our Electrochemistry Metals Kit, but any metals and salts can be used in this experiment.
  • Use fresh iron solutions for the best results. 
  • Make sure to prepare the Electrochemistry Half-Cell Plate before use—for best results, fill and soak all wells overnight with the 1 M KNO3 solution. 
  • As an extension, ask students to use the Nernst equation to determine the concentration of copper ion solution in a cell of unknown concentration.

Electrochemistry may seem abstract at first, but when students engage in recreating scientific proofs and connecting them to observable real-world phenomena, they gain something invaluable: the ability to see the science behind the numbers and imagine themselves engaging in discovery and innovation. 

A Mole Lot of Fun: Chemistry Investigations from Avogadro’s Number to Electrodes

Looking for more? Check out our “A Mole Lot of Fun” webinar, which walks through both of these experiments and provides additional tips and tricks to help your students visualize abstract ideas like Avogadro’s number and electron transfer.


Do you have innovative ways of teaching electrochemistry with Vernier? Let us know at blog@vernier.com or share with us on social! Questions? Reach out to chemistry@vernier.com, call 888-837-6437, or drop us a line in the live chat.

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