Scribd
Upload
117 views3 pages

Name: Alburo & Bacani Date Performed: May 3, 2017 Section: 3 Che C Group No. 1 Date Submitted: May 8, 2017

The document summarizes an experiment on the electromotive force (emf) of 12 galvanic cell combinations. It provides tables with the theoretical and experimental emf values and percent errors for each combination. It also includes cell diagrams depicting the half-cell reactions and overall cell reactions. In conclusion, the document discusses how factors like electrode interchange or submersion of clips could impact results, and the significance of electronegativity and electron affinity of electrodes on the emf.

Uploaded by

Chin Ramos
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
117 views3 pages

Name: Alburo & Bacani Date Performed: May 3, 2017 Section: 3 Che C Group No. 1 Date Submitted: May 8, 2017

The document summarizes an experiment on the electromotive force (emf) of 12 galvanic cell combinations. It provides tables with the theoretical and experimental emf values and percent errors for each combination. It also includes cell diagrams depicting the half-cell reactions and overall cell reactions. In conclusion, the document discusses how factors like electrode interchange or submersion of clips could impact results, and the significance of electronegativity and electron affinity of electrodes on the emf.

Uploaded by

Chin Ramos
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
Available Formats
Download as DOCX, PDF, TXT or read online on Scribd
You are on page 1/ 3

Name: Alburo & Bacani Date Performed: May 3, 2017

Section: 3 ChE C Group No. 1 Date Submitted: May 8, 2017

Treatment of Data

Experiment No. 7
Electromotive Force of Galvanic Cells

No Combination Cathode Anode Theoretical Experimental % Error


1 Zn (0.1 M), Pb Pb Zn 0.6360 0.4 37.10
2 Zn (0.1 M), Fe Fe Zn 0.721 0.3 871.49
3 Zn (0.1 M), Cu Cu Zn 1.0990 1.0 9.0
4 Zn (0.1 M), Al Zn Al 1.0105 0.8 20.83
5 Pb, Cu Cu Pb 0.4650 0.4 13.98
6 Pb, Fe Pb Fe 1.6975 1.4 17.53
7 Pb, Al Pb Al 2.9322 0.7 76.13
8 Pb, Zn (0.5 M) Pb Zn 0.6134 0.6 2.18
9 Fe, Cu Fe Cu 1.2325 0.5 59.43
10 Fe, Al Fe Al 3.9927 3.8 4.83
11 Fe, Zn (0.5 M) Fe Zn 2.3139 0.6 73.07
12 Al, Zn (0.5 M) Zn Al 1.0418 0.8 23.15

Cell Diagram
Electrodes Cell Diagram
Zn/Zn2+ & Pb/Pb2+ Zn|ZnSO4(aq)||Pb(NO3)2,(aq)|Pb
Zn/Zn2+ & Fe2+, Fe3+ Zn|ZnSO4(aq)||Fe3+(aq)|Fe
Zn/Zn2+ & Cu/Cu2 Zn|ZnSO4(aq)||CuSO4(aq)|Cu
Al/Al3+ & Zn/Zn2 Al|Al(NO3)2(aq)|| Zn|ZnSO4(aq)
Pb/Pb2+& Cu/Cu2 Pb(NO3)2,(aq)|Pb||CuSO4(aq)|Cu
Fe2+, Fe3+& Pb/Pb2+ Fe3+(aq)|Fe||Pb(NO3)2,(aq)
Al/Al3+ & Pb/Pb2+ Al|Al(NO3)2(aq)||Pb|Pb(NO3)2(aq)
Cu/Cu2& Fe2+, Fe3+ CuSO4(aq)|Cu||Fe3+(aq)|Fe
Al/Al3+ & Fe2+, Fe3+ Al|Al(NO3)2(aq)||Fe3+(aq)|Fe

Overall cell reaction


Electrodes Overall reaction Emf (theo)
Zn/Zn2+ & Pb/Pb2+ Zn + Pb2+ Zn2+ + Pb 0.6360
Zn/Zn2+ & Fe2+, Fe3+ Zn +Fe3+ Zn2+ +Fe 0.721
Zn/Zn2+ & Cu/Cu2 Cu2+ 1.0990
Al/Al3+ & Zn/Zn2 1.0105
Pb/Pb2+& Cu/Cu2 0.4650
Fe2+, Fe3+& Pb/Pb2+ 1.6975
Al/Al3+ & Pb/Pb2+ Al + Pb2+ Pb + Al3+ 2.9322
Cu/Cu2& Fe2+, Fe3+ Cu + Fe2+ Fe + 0.6134
Al/Al3+ & Fe2+, Fe3+ 1.2325
3.9927
2.3139
1.0418

. Answers to Questions

1 What could have happened if the alligator clips were also submerged into the solution
when the half-cells were being prepared? How would this affect the result of the
experiment and why?

If the allligator clips were submerged into the solution, the results would deviate
from the ideal voltage reading as the clips would oxidize or reduce and would cause
changes in the voltage reading. This is because the alligator wires are made up of a
completely different metal. The galvanic cell under study would not just be a
combination of two electrodes, thus, a discrepancy in the results.

2 What does a negative reading in the multimeter indicate?

A negative reading in the multimeter indicates that the created combination of


galvanic cell would most likely be non-spontaneous. This happens when the negative
terminal of the multimeter is attached to the cathode instead of the anode and the positive
is attached to anode instead of cathode.

3 How would the result of the experiment be affected if the electrodes of the half-cells were
interchanged instead of the multimeter terminal?

If electrodes instead of multimeter terminals were interchanged whenever a


negative reading is observed, then the multimeter would not display a reading. It would
cause no movement of electrons because the electrodes are not submerged in their
respective electrolyte solution.

4 What is the significance of electron affinity and electronegativity of the electrodes on the
emf of the galvanic cell? Explain briefly.

The more electronegative element in the galvanic cell would more likely to reduce
since it has a stronger tendency to accept electrons than the less electronegative element.
So, the more electronegative would always function as cathode in the reaction and the
other would be the anode. Similarly, the element which has a higher electron affinity is
the cathode. Therefore, the element with the greater electron affinity and electronegativity
of the electrodes governs the chemical reaction and becomes the cathode.

You might also like