Electrochemical

Rachel Speaker

Mrs. Shafer

Lab Report

3-23-11

Electrochemical Cells

Objective:

The objective of part one of this lab is to construct a table listing the reduction potentials of a series of metal ions in order or ease of reduction. In part the objective is to use the Nernst equation to determine the voltage of a cell in which the zinc half-cell is connected to a solution containing a trace of Ag+ ions in a 1.0M solution of sodium chloride.

Part 1

Data: Voltage of each half-cell versus zinc electrode

| Voltage | Anode | Cathode |

Zn versus Ag | 1.31 | Zn | Ag |

Zn versus Cu | 0.90 | Zn | Cu |

Zn versus Fe | 0.43 | Zn | Fe |

Zn versus Mg | 0.52 | Zn | Mg |

Zn versus Pb | 0.40 | Zn | Pb |

Predicted and Measured Cell Potentials

Anode | Cathode | Equation for the Cell Reaction | Predicted Potential from Experimental Data | Measured Potential |

Mg | Pb | Mg2+ + Pb→Mg+Pb2+ | -.012 | -.88 |

Cu | Ag | 2Ag+ +Cu → 2Ag + Cu2+ | .41 | .39 |

Fe | Cu | 2Fe3+ + Cu → 2Fe2+ + Cu2+ | .47 | .47 |

Fe | Ag | Ag+ + Fe2+ → Ag + Fe3+ | .88 | .88 |

Pb | Cu | Cu +Pb2+ → Cu2+ +Pb | .50 | .51 |

Mg | Cu | Cu + Mg2+ → Cu2+ + Mg | .38 | 1.34 |

Part 2: Data Table

| Voltage | Anode | Cathode |

Zn(s) l Zn2+(1.0M) ll Cu2+(.0010M) l Cu(s) | 0.86V | Zn | Cu |

Equation for Cell Reaction | Predicted Potential | Measured PotentialZn |

Zn + 2Ag+ → Zn2+ + 2Ag | 0.8112V | 0.86V |

Reduction Equations for Each Ion Arranged in Decreasing Order of Potential

Reduction Equation | Electrode Potential using Zinc as the standard, E°Zn | Accepted Electrode Potential using Hydrogen as Standard, E° | E°Zn - E° |

Ag+ + e- → Ag | 1.31V | 0.80V | 0.51V |

Fe3+ + e- → Fe2+ | 0.43V | 0.77V | -0.34V |

Cu2+ + 2e- → Cu | 0.90V | 0.34V | 0.56V |

Pb2+ + 2e- → Pb | 0.40V | -0.126V | 0.526V |

Zn2+ + 2e- → Zn | 0 | -0.763V | 0.763V |

Mg2+ + 2e- → Mg | 0.52V | -2.37V | 2.89V |

Calculations:

Volume of one drop = mass of 1 drop X 1L

1.00g/ml...