Expt. 15 complete.docx - Penn State CHEM 113 Experiment 15...

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Penn State CHEM 113 1 Experiment 15: Redox and Electrochemistry Experiment Goal. Complete before lab. Throughout this lab, we will study redox reactions, construct electrochemical cells, obtain cell potential calculations, and carry out analysis of metal samples. Procedure: Thompson, S. PSU Chemtrek: Expt. Redox Equilibria and Electrochemistry; Keiser, J., Hayden- McNeil Publishing: Plymouth, MI, 2020, pp 15-1 – 15-18. Section A. Redox Reaction Investigation Pre-lab data collection and observations. Complete before lab. The instructor places 2 small strips of both Zinc and Copper metal on a white reaction surfaces about 4 inches apart and labels them. Then 1 drop of copper sulfate is added on top of the zinc strip. The blue solution quickly turns black on top of the strip (spontaneous). Similarly, 1 drop of zinc sulfate is added atop the copper foil, with no reaction observed (non-spontaneous). Section B. A Small-Scale Electrochemical Cell Pre-lab data collection and observations. Complete before lab. The instructor uses filter paper marked with 3 overlapping circles labeled with the 3 solutions being used Copper Sulfate, Zinc Sulfate and Potassium Nitrate (the salt bridge). She then adds 2 drops of each metal ions solutions to their labeled section on the paper and 2 drops of KNO3 between them. Then 1 piece of copper and 1 zinc foil is added on top of their respective solutions on the filter paper. Now she uses a multi meter to find a voltage reading when placing each probe on the zinc and copper foils. This is then repeated a few times and the voltage value is recorded for each trial in table 1 below. Probes swapped = - 1.009V Trial #: Voltage (V) 1 1.019 2 1.017 3 1.015 4 1.012 5 1.009 Average: 1.014 Table 1: Voltage by zinc & copper foil
Question 1: (a) What is the net redox equation for the spontaneous reaction that you observed occurring in Parts A and B?

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