Completed Chemistry 30 Assignment for Electrochemical changes

Module 4: Lesson 2 ASSIGNMENT Total /43 Read all parts of your assignment carefully, and record your answers in the appropriate places. If you have difficulty with an assignment, review the relevant sections of the lesson and the textbook. Be sure to proofread your answers carefully before submitting your Assignment. Lesson 2 Assignment: Design of Commercial Cells Part 1: Lab—Building Voltaic Cells Pre-Lab Complete the following tables to make predictions about the voltaic cells referenced. You will complete the row “Observed Cell Potential” while or after viewing the virtual investigation. (6 marks each) Cell 1 Zn(s) ?Zn2+(aq) ? Cu2+(aq) ?Cu(s) Diagram of Operating Cell direction of electron movement direction of ion movement Anode Zn(s)| Zn2+(aq) Anion movement ? Cation movement ? Electron movement ? Cathode Cu(s) | Cu2+(aq) Reduction Half-Reaction Cu2+(aq) + 2e- Cu(s) Oxidation Half-Reaction Zn(s) Zn2+(aq) + 2e- Net Cell Reaction Cu2+(aq) + Zn(s) Cu(s) + Zn2+(aq) Predicted Standard Cell Potential 1.1V Observed Cell Potential 1.100V Spontaneous (Yes or No) Yes Cell 2 Zn(s) ?Zn2+(aq) ? Fe2+(aq) ?Fe(s) Diagram of Operating Cell direction of electron movement direction of ion movement Anode Zn(s) | Zn2+(aq) Anion movement ? Cation movement ? Electron movement ? Cathode Fe2+(aq) | Fe(s) Reduction Half-Reaction Fe2+(aq) +2e- Fe(s) Oxidation Half-Reaction Zn(s) Zn2+(aq) + 2e- Net Cell Reaction Fe2+(aq) + Zn(s) Fe(s) + Zn2+(aq) Predicted Standard Cell Potential 0.31V Observed Cell Potential 0.310V Spontaneous (Yes or No) Yes Cell 3 Fe(s) ?Fe2+(aq) ? Cu2+(aq) ?Cu(s) Diagram of Operating Cell direction of electron movement direction of ion movement Anode Fe(s) | Fe2+(aq) Anion movement ? Cation movement ? Electron movement ? Cathode Cu2+(aq) | Cu(s) Reduction Half-Reaction Cu2+(aq) + 2e- Cu(s) Oxidation Half-Reaction Fe(s) Fe2+(aq) + 2e- Net Cell Reaction Cu2+(aq) + Fe(s) Cu(s) + Fe2+(aq) Predicted Standard Cell Potential 0.79V Observed Cell Potential 0.790V Spontaneous (Yes or No) Yes Cell 4 Mg(s) ?Mg2+(aq) ? Zn2+(aq) ?Zn(s) Diagram of Operating Cell direction of electron movement direction of ion movement Anode Mg(s) | Mg2+(aq) Anion movement ? Cation movement ? Electron movement ? Cathode Zn2+(aq) | Zn(s) Reduction Half-Reaction Zn2+(aq) + 2e- Zn(s) Oxidation Half-Reaction Mg(s) Mg2+(aq) +2e- Net Cell Reaction Zn2+(aq) + Mg(s) Zn(s) + Mg2+(aq) Predicted Standard Cell Potential 1.61V Observed Cell Potential 1.613V Spontaneous (Yes or No) Yes Cell 5 Mg(s) ?Mg2+(aq) ? Fe2+(aq) ?Fe(s) Diagram of Operating Cell direction of electron movement direction of ion movement Anode Mg(s) | Mg2+(aq) Anion movement ? Cation movement ? Electron movement ? Cathode Fe2+(aq) | Fe(s) Reduction Half-Reaction Fe2+(aq) + 2e- Fe(s) Oxidation Half-Reaction Mg(s) Mg2+(aq) + 2e- Net Cell Reaction Fe2+(aq) + Mg(s) Fe(s) + Mg2+(aq) Predicted Standard Cell Potential 1.92V Observed Cell Potential 1.920V Spontaneous (Yes or No) Yes Cell 6 Mg(s) ?Mg2+(aq) ? Cu2+(aq) ?Cu(s) Diagram of Operating Cell direction of electron movement direction of ion movement Anode Mg(s) | Mg2+(aq) Anion movement ? Cation movement ? Electron movement ? Cathode Cu2+(aq) | Cu(s) Reduction Half-Reaction Cu2+(aq) + 2e- Cu(s) Oxidation Half-Reaction Mg(s) Mg2+(aq) +2e- Net Cell Reaction Cu2+(aq) + Mg(s) Cu(s) + Mg2+(aq) Predicted Standard Cell Potential 2.71V Observed Cell Potential 2.711V Spontaneous (Yes or No) Yes Analysis Compare the predicted standard cell potentials with the observed values. Was there a discrepancy? Provide possible reasons for any differences. (2 marks) Answer: My predicted standard cell values had one less decimal point than the observed values. I think the difference could have occurred because my data booklet had three decimal places and not four. The discrepancy between my answer and the observed answers were very minimal. Suggest a reason why very small voltaic cells were constructed for this investigation. (1 mark) Answer: The cells are basic and easy to construct, they don’t need detail the other cells do. Fewer chemicals and metal variations. Would you expect a difference in the cell potential if larger cells had been constructed and tested? Suggest an aspect of a cell’s function that may be affected by using a larger cell that contains a greater quantity of chemicals. (2 marks) Answer: I think there wouldn’t be a difference in cell potential with a larger cell and the voltage value would stay the same. But I also think the energy supply would lengthen because there are more atoms in a larger cell. Part 3: Cell Potential A Ni-Cd rechargeable cell has a cell potential of +1.30 V. If the cathode has a potential of +0.49 V, what is the anode’s potential? (2 marks) Answer: E°(cell)=E°(reduction)-E°(oxidation) +1.30V=(+0.49V)-E°(oxidation) E°(oxidation)=-1.30V+0.49VE° (oxidation)=-0.81V Submit your completed Assignment to Moodle at the end of this lesson.