Exp. 8: Galvanic Cells Report Sheet Part A. Cell Potential of some redox couples Redox reaction Half-cell Half-cell Ecel
Posted: Tue Nov 23, 2021 8:29 am
answer the following questions:
1. figure for Ecell vs pCu: (graph)
2. Equation of the line
3. Cu concentration of unknown
4. Error statement
Exp. 8: Galvanic Cells Report Sheet Part A. Cell Potential of some redox couples Redox reaction Half-cell Half-cell Ecell theoretical (V) Ecell measured (V) 1 Zn2+Zn Outlu 1.10 0.918 2 Zn2+/Zn. Mg2+/Mg 1.61 0.900 3 Zn +/Zn Fe2+ Fe 0.32 0.325 4 Cut/Ou Mg2+/Mg 2.03 | 1.785 5 5 Cust/Cu Fe-t/Fe 0.78 0.567 6 OD Mg2+/Mg Fest Fe 11193 1 243 Calculations (Just show one) Ecell Theoretical for Zn and Cu: Zn -- Zn^+2 + 2en. Cu'+2 + 2e ou Zn + Our+2 Zn2 +Cu 0.76 - (0.34) 0.76 + 0.34 = 1 10V
Reactions 1. Zn + Cu^+2 – Zn^+2 +Ou 2. Zn +Mg^+2 — Zn^+2 + Mg 3. Zn + Fe^+2 - Fe + Zn^+2 4. Cu + Mg^+2 — Cu^+2 + Mg 5. Cu + Fe^+2 — Cu^+2 + Fe 6. Mg + Fe^+2 — Fe + Mg^+2
Part B. Effect of concentration on cell potential Half-Cell Half-Cell Ecell (V) 1.0 M Cu?-/Cu 0.001 M Cu-t/Cu 0.382 1.0 M Cu2+/Cu + 6 MINH 0.395 1.0 M Cup-/Cu + 0.2 M Nas 0.411 Comment on how and why the potential changes with each addition, 1. The value of reduction potential decreases when the solution of a lower concentration of copper ion is added to it. 2. With NH3 added to the solution of copper the value of reduction potential decreases due to the increased concentration of copper ions 3. The addition of Na2S increases the reduction potential of the cell due to the increase of the concentration.
Part C. Determination of unknown concentration using the Nernst equation Half-Cell Half-Cell -log [Cu?'], pCu Ecell (V) theoretical Ecell (V) measured Zn2+/Zn 1 x 10-7 M Cu2+/Cu 0.794 Zn2+1 Zn 1 x 10-5 M Cu2+/Cu 0.805 Zn2+/Zn 1 x 10' M Cu2+/Cu 0.867 Zn2+/Zn 1 x 10-1 M Cu2+/Cu 0.871 Zn2+/Zn unknown NA 0.875 뜻