NEW virtual options below!
In this electrochemistry lab, students proceed through a prior knowledge activity, practice creating and using a voltaic cell and use a model designed to simulate the particulate level activity within that cell. The teacher checks for student understanding at specific points as groups work together. A discussion follows to help clarify ideas. A student document can be found in the supporting information below.
This lab was originally created and published as part of the second cohort of Target Inquiry at Grand Valley State University. Teachers can find the Teacher Document including the cell and particles that can be printed and distributed to groups of students (see figure 1). Those that don't have an account can register for one (for free) and gain access to over 80 activities for chemistry and other sciences. The Teacher Document also outlines common misconceptions that are addressed in the lab.
Figure 1: Students move the pieces on the in-class laminated paper model
Melissa Hemling created virtual options for manipulatives used in this lab and has generously agreed to allow ChemEd X to add them here. (Check out Melissa's ChemEd X Blog!)
This Google Slides link provides the cell and manipulative particles (see figure 2). The manipulative particles are stacked in the margins and students simply slide them onto the model.
Melissa also created a Classkick manipulative for teachers using that platform (Note that Classkick works best in the Chrome browser.)
Both of these options can be used with the original student document shared in the Supporting Information below. The teacher can demonstrate the prior knowledge activity and the working cell live or by creating a video as their situation allows. Alternatively, a quick search of YouTube or Vimeo yields a large assortment of videos that can be used.
Additionally, Kelly Burleson contributed her own modification of the Energizer Lab assignment in her ChemEd X blog post, Stop Motion Animation Galvanic Cell Process, published 8/12/19 that could be combined with the virtual manipulatives above.
Figure 2: Virtual manipulatives created in Google Slides by Melissa Hemling
- The student will draw and label the parts of an electrochemical cell.
- The student will identify and explain the reactions occurring at the anode and cathode.
- The student will explain the flow of electrons in relation to the cell and the resulting voltage.
- The student will explain the movement of cations and anions in the cell.
About one 60 minute class period for lab and manipulative procedure.
- 0.10 M CuSO4
- 1.0 M CuSO4
- 1.0 M ZnSO4
- 2-10cm pieces of zinc wire
- 1-10cm copper wire
- test tube
- voltmeter
- electronic balance
- Voltaic Cell Kit OR you can set up a cell using a 400 mL beaker, a porous cup and alligator clip wires.
In the prior knowledge section, students place a zinc paperclip in dilute copper II sulfate solution. After they let it sit for 5 minutes, they carefully remove it from the solution and observe. This provides an opportunity to revisit oxidation and reduction and check for understanding of those concepts before moving in to the lab.
Figure 3: Prior Knowledge activity prior to Energizer Lab procedure.
Part A: Students may use beakers and a salt bridge or a Voltaic Cell Kit as seen here. I often have at least three different versions for student groups to choose from. If only one type is available, videos of other types, including microscale versions, are easy to find. Be sure that students unhook the voltmeter while the cell sits unattended to help ensure a maximum change in mass. Note: Notice that both half reactions from the Prior Knowledge Section are present. They are separated in this cell so that there can be no direct interaction between zinc atoms and Cu2+ ions. The porous cup keeps the Cu2+ ions from coming into contact with the zinc strip.
Part B: Check to make sure students have set up the model per the diagram provided in the student document before they work through the procedure. While students work through the model, check for understanding of each group. Get students to say that the Zn2+ goes into solution. Ask them what happens at this point to keep the charge within each cell neutral. What happens at the cathode with the electron? Have students explain the electron flow, ion flow through the semi-permeable membrane, and cation/ anion change at the electrodes. Initial Check Point at end of Part B.
Part C: Students should observe the electrode. If students have trouble seeing a mass change within the lab period, keep one cell running for a longer time period (several hours possibly) until a change in size can be seen and then show to students the following day. It can be difficult to measure the actual mass but students only need to visually see that one electrode gains mass and the other losses mass. The mass of the zinc electrode should decrease and the mass of the copper electrode should increase. The zinc electrode may seem dull because it is losing zinc atoms. The copper electrode may look shiny because it is gaining copper atoms.
See the Student Version provided in the Supporting Information for the Complete Procedure.
See the Student Document provided in the Supporting Information for associated questions as they are found throughout the document.
Prep cupric sulfate and zinc sulfate solutions. Set up voltaic cell kits or alternative equipment.
The model in this lab is adapted from the following article:
Huddle, Penelope Ann and White, Margaret Dawn, Using a Teaching Model to Correct Known Misconceptions in Electrochemistry, Journal of Chemical Education, 2000, 77 (1), p. 104- 110.
Research related to the Energizer Lab activity is discussed in the following article:
Cullen, Deanna M. and Pentecost, Thomas C., Model Approach to the Electrochemical Cell: An Inquiry Activity, Journal of Chemical Education, 2011, 88 (11), 1562-1564.
Safety
General Safety
General Safety
For Laboratory Work: Please refer to the ACS Guidelines for Chemical Laboratory Safety in Secondary Schools (2016).
For Demonstrations: Please refer to the ACS Division of Chemical Education Safety Guidelines for Chemical Demonstrations.
Other Safety resources
RAMP: Recognize hazards; Assess the risks of hazards; Minimize the risks of hazards; Prepare for emergencies
NGSS
Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
*More information about all DCI for HS-PS1 can be found at https://www.nextgenscience.org/dci-arrangement/hs-ps1-matter-and-its-interactions and further resources at https://www.nextgenscience.org.
Students who demonstrate understanding can construct and revise an explanation for the outcome of a simple chemical reaction based on the outermost electron states of atoms, trends in the periodic table, and knowledge of the patterns of chemical properties.
Assessment is limited to chemical reactions involving main group elements and combustion reactions.
Examples of chemical reactions could include the reaction of sodium and chlorine, of carbon and oxygen, or of carbon and hydrogen.
Students who demonstrate understanding can use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.
*More information about all DCI for HS-PS1 can be found at https://www.nextgenscience.org/dci-arrangement/hs-ps1-matter-and-its-interactions and further resources at https://www.nextgenscience.org.
Students who demonstrate understanding can use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction.
Assessment does not include complex chemical reactions.
Emphasis is on using mathematical ideas to communicate the proportional relationships between masses of atoms in the reactants and the products, and the translation of these relationships to the macroscopic scale using the mole as the conversion from the atomic to the macroscopic scale. Emphasis is on assessing students’ use of mathematical thinking and not on memorization and rote application of problem - solving techniques.
Students who demonstrate understanding can develop and use models to illustrate that energy at the macroscopic scale can be accounted for as a combination of energy associated with the motions of particles (objects) and energy associated with the relative position of particles (objects).
*More information about all DCI for HS-PS3 can be found at https://www.nextgenscience.org/topic-arrangement/hsenergy.
Students who demonstrate understanding can develop and use models to illustrate that energy at the macroscopic scale can be accounted for as a combination of energy associated with the motions of particles (objects) and energy associated with the relative position of particles (objects).
Examples of phenomena at the macroscopic scale could include the conversion of kinetic energy to thermal energy, the energy stored due to position of an object above the earth, and the energy stored between two electrically-charged plates. Examples of models could include diagrams, drawings, descriptions, and computer simulations.
Students who demonstrate understanding can design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.
*More information about all DCI for HS-PS3 can be found at https://www.nextgenscience.org/topic-arrangement/hsenergy.
Students who demonstrate understanding can design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy.
Assessment for quantitative evaluations is limited to total output for a given input. Assessment is limited to devices constructed with materials provided to students.
Emphasis is on both qualitative and quantitative evaluations of devices. Examples of devices could include Rube Goldberg devices, wind turbines, solar cells, solar ovens, and generators. Examples of constraints could include use of renewable energy forms and efficiency.
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Comments 2
Question on Part A
Deanna - this lab is great. I really like the virtual options. One quesiton about part A...Why is it necessary to unhook the voltmeter to ensure a maximum change in mass? Why wouldn't the mass change with the volt meter connected?
Voltmeter
Thank you! Some teachers weren't seeing a mass change so I asked a mentor. I was told that the resistance in the voltmeter could slow down the chemical reaction so my advice is based on their direction.
I appreciate Melissa's virtual options too!