Teacher Notes
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Teacher Notes![]() Electrochemistry Target LabGuided-Inquiry Wet/Dry KitMaterials Included In Kit
Copper foil, Cu(s), 3" x 12" sheet
Copper(II) nitrate solution, Cu(NO3)2, 1.0 M, 100 mL Iron nail, Fe(s), 12 Iron(III) nitrate solution, Fe(NO3)3, 1.0 M, 100 mL Lead foil, Pb(s), 3" x 12" sheet Lead nitrate solution, Pb(NO3)2, 1.0 M, 100 mL Magnesium nitrate solution, Mg(NO3)2, 1.0 M, 100 mL Magnesium ribbon, Mg(s), 15 Potassium nitrate solution, KNO3, 1.0 M, 200 mL Silver foil, Ag(s), 5 g Silver nitrate solution, AgNO3, 1.0 M, 100 mL Zinc strip, Zn(s), 5" x ½", 10 Zinc nitrate solution, Zn(NO3)2, 1.0 M, 100 mL Filter paper Pipets, Beral-type, 120 Additional Materials Required
Beaker, 50-mL
Graduated cylinder, 10-mL Reaction plate, 24-well Sandpaper or steel wool Scissors, Heavy-duty† Voltmeter/multimeter *for each lab group) †for Prelab Preparation Prelab Preparation
Safety PrecautionsSilver nitrate solution is toxic by ingestion and irritating to body tissue. It also stains skin and clothing. Lead nitrate solution is a possible carcinogen. It is also moderately toxic by ingestion and inhalation, and is irritating to eyes, skin and mucous membranes. Zinc nitrate solution is slightly toxic by ingestion and corrosive to body tissue/severe tissue irritant. Copper(II) nitrate solution is slightly toxic by ingestion; it is irritating to skin, eyes and mucous membranes. Iron(III) nitrate solution is corrosive to body tissue. Magnesium nitrate solution is a body tissue irritant. Wear chemical splash goggles, chemical-resistant gloves and apron. Remind students to wash hands thoroughly with soap and water before leaving the laboratory. Please review Safety Data Sheets for additional safety, handling and disposal information. DisposalPlease consult your current Flinn Scientific Catalog/Reference Manual for general guidelines and specific procedures, and review all federal, state and local regulations that may apply, before proceeding. The lead nitrate solution may be handled according to Flinn Suggested Disposal Method #27f. The silver nitrate solution may be handled according to Flinn Suggested Disposal Method #11. The remaining solutions may be rinsed down the drain with excess water according to Flinn Suggested Disposal Method #26b. Lab Hints
Teacher Tips
Further ExtensionsAlignment to the Curriculum Framework for AP® Chemistry Correlation to Next Generation Science Standards (NGSS)†Science & Engineering PracticesAsking questions and defining problemsDeveloping and using models Planning and carrying out investigations Analyzing and interpreting data Using mathematics and computational thinking Constructing explanations and designing solutions Obtaining, evaluation, and communicating information Disciplinary Core IdeasHS-PS1.A: Structure and Properties of MatterHS-PS1.B: Chemical Reactions HS-PS2.B: Types of Interactions HS-PS3.A: Definitions of Energy HS-PS3.B: Conservation of Energy and Energy Transfer HS-PS3.D: Energy in Chemical Processes HS-ETS1.B: Developing Possible Solutions HS-ETS1.C: Optimizing the Design Solution Crosscutting ConceptsPatternsCause and effect Scale, proportion, and quantity Systems and system models Energy and matter Structure and function Stability and change Performance ExpectationsHS-PS1-1. Use the periodic table as a model to predict the relative properties of elements based on the patterns of electrons in the outermost energy level of atoms. Answers to Prelab Questions
Sample DataPart 1: Zinc Reference Standard
Possible voltage assignments: 0.80 V {12386_Data_Table_5}
Numbers may vary for students. Check the students own reference chart and calculations, when reviewing how the group performs on the Voltage Challenge.
ReferencesCollege Board, The. 2014. “AP Chemistry Course and Exam Description, rev. ed.” NY: The College Board. Accessed June 7, 2017. http://media.collegeboard.com/digitalServices/pdf/ap/ap-chemistry-course-and-exam-description.pdf Recommended Products
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Student Pages
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Student Pages![]() Electrochemistry Target LabIntroductionBatteries power so many of the devices we use on a daily basis. It’s these electrochemical reactions that keep our lives and our devices charged! In this lab, you will create a half cell reduction potential data table using a zinc half-cell as your reference standard. Then your instructor will give you a voltage requirement. Using the materials available and your half-cell reduction potential data table, you’ll have to build a battery to your instructor’s specifications. See how close you can get to the actual voltage! Concepts
BackgroundAn electrochemical cell results when an oxidation reaction and a reduction reaction occur, and the resulting electron transfer between the two processes occurs through an external wire. The oxidation and reduction reactions are physically separated from each other and are called half-cell reactions. A half-cell can be prepared from almost any metal in contact with a solution of its ions. Since each element has its own electron configuration, each element develops a different electrical potential, and different combinations of oxidation and reduction half-cells result in different voltages for the completed electrochemical cell. Cu2+(aq) + 2e– → Cu(s) E° = 0.34 V Al(s) → Al3+(aq) + 3e– E° = +1.66 V The reduction potential and the oxidation potential are added to find the cell voltage:3Cu2+(aq) + 2Al(s) → 3Cu(s) + 2Al3+(aq) A cell representation such as the following: Zn(s) | Zn2+(1.0 M) || Cu2+(1.0 M) | Cu(s) means that a cell is constructed of zinc metal dipping into a 1.0 M solution of Zn2+. The symbol “|” refers to a phase boundary. The symbol “||” indicates a salt bridge between the zinc ion solution and the copper ion solution. The second half-cell is copper metal dipping into a 1.0 M solution of copper ions. The anode is on the left (where oxidation occurs) and the cathode is on the right (where reduction occurs). In this laboratory, a “standard” table of electrode potentials is constructed. A value of 0.00 volts is assigned to the electrode made from zinc metal in a 1.0 M solution of zinc ions. The voltage values should correlate with those found in published tables, differing only by the value of E° for the standard zinc electrode. Published standard values are measured in solutions that have very small electrical resistance. The resistance of the experimental cell will probably cause a lowering of measured values from the ideal values. The table of standard potentials assumes that all ion concentrations are 1.0 M, gas pressures are 1 atm, and temperature is 25 °C. Experiment OverviewThe purpose of this activity is to complete the homework assignment prior to lab to promote conceptual understanding of galvanic cells. You will first review and analyze redox reactions and electrochemical cells in the homework assignment. After analyzing your homework assignment, you will then design a procedure to create your own half-cell reduction potential using a zinc half-cell as your reference standard. You will then have to construct a cell of a given voltage from your instructor. See how close your cell is to the predicted voltage! Prelab QuestionsComplete the following homework set and write a lab procedure to be approved by your instructor prior to performing the lab. Along with your procedure, you will turn in any graphs, tables or figures you were asked to create in this homework set, and answers to the questions. Use a separate sheet of paper, if needed.
Safety PrecautionsSilver nitrate solution is toxic by ingestion and irritating to body tissue. It also stains skin and clothing. Lead nitrate solution is a possible carcinogen. It is also moderately toxic by ingestion and inhalation; irritating to eyes, skin and mucous membranes. Zinc nitrate solution is slightly toxic by ingestion; it is corrosive to body tissue/severe tissue irritant. Copper(II) nitrate solution is slightly toxic by ingestion and irritating to skin, eyes and mucous membranes. Iron(III) nitrate solution is corrosive to body tissue. Magnesium nitrate solution is a body tissue irritant. Wear chemical splash goggles, chemical-resistant gloves and apron. Wash hands thoroughly with soap and water before leaving the laboratory. |