174287368-Electrochemical-Lab-Report

Lab Report
Electrochemistry: Voltaic and Electrolytic
cells
by Josiah Richardson
Lab Partners: Kenny Nguyen
Professor David Haas
Lab Day and Start Time: Tuesdays 1:40pm
Date Experiment Performed: April 23rd, 2013
Date Lab Report Submitted: May 2nd, 2013
Introduction
In this lab, we created an electrochemical cell using a 9-volt battery to cause the electrolysis of a sodium iodide solution. Using the nernst equation, we will determine the cell potential for various concentrations and determine whether our experimental results coincide with the actual experiment. The nernst equation is as follows:
E = E o– RT ln Q where E is the potential of the cell.
nF E o is the potential of the cell at standard conditions
R is the gas constant 8.314 J/mol-K
T is the temperature in Kelvin
n are the moles of electrons transNirred
F is
Faraday’s constant (96500 Coulombs/mole)
and Q is the reaction quotient (products/reactants)
At standard condtions (25 C, 1 ATM, 1 Mol) we will use the nearst equation which is as follows:
E cell = E˚cell - 0.05916 log [products]p
n [reactants]r
We will use these aforementioned equations and the forthcoming materials to accomplish our goal of creating and analyzing our electrochemical cell.
Materials
black and red coated wire with alligator clips copper strip, nickel strip
pipet DC voltmeter
zinc strip, lead strip Phenolphthalein
0.50 M KNO3, 0.10 M ZnSO4, 0.10M NiSO4, 0.10 M
9-Volt battery with terminal Pb(NO3)2, 0.0020 M ZnSO4, and 0.10 M CuSO4
plastic cups Safety glasses
Procedure“Electrochemistry: Voltaic and Electrolytic cells”, CHEM 102 General Chemistry Lab Experiment April 2013. The laboratory procedure in the worksheet was followed without modification.
Data
PART 1:
1. Zn / Zn+2(0.10M) // Cu+2(0.10M) / Cu without the salt bridge 0.00 V
2. Zn /Zn+2(0.10M) // Cu+2(0.10M) / Cu with the salt bridge
1.07 V
3. Pb / Pb+2(0.10M) // Cu+2(0.10M) / Cu with the salt bridge
0.85mV
4. Ni / Ni+2(0.10M) // Cu+2(0.10M) / Cu with the salt bridge
0.02 V
5.Zn / Zn+2(0.0020M) // Cu+2(0.10M) / Cu with the salt bridge 1.07 V
Table 1. Voltage of compounds data
Figure 2. An Electrolytic Electrochemical Cell
Results and Discussion
We observed many amazing chemical reactions in this laboratory experiment. We watched as one of the metal alligator clips fizzed when we hooked it up to the 9-volt battery and the other corroded as if it was rusting at an exponential rate. When we added the phenolphthalein to the solution it changed the solution to a pink color coming from one of the alligator clips, telling us that the clip that was corroding was being reduced and the other clip that fizzed was being oxidized.
Conclusion
In this lab, we learned how to draw an electrolytic cells and determine what is being oxidized and what is being reduced. We also learned how to write the shorthand notation for the
electrochemical cells. We used various solutions with their compounds and hooked them up to
a 9 volt battery and recorded our observations. To solve equations where we needed to find the standard potentials of the cells, we used the nearst equation and the nearnst equation, respectively. Out of all the laboratory experiements that we have been a part of, this one was the most pre-knowledge based. My overall experience was an enjoyable one and I look forward to future labs of the same magnitude.。