Transcript Chemistry How - ChemistryIBWYA

G4
Group #1 ★
Can We ‘Grow’ Electricity?!
Zhi Wei Ngion, Tiffany Park, Leo Siha, Amy Wan, Sherry Zhang
Introduction
• Generating power produces
– Pollution
– Global warming
• Lemon and potato as power sources:
– Clean
– Renewable
– Biodegradable
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Physics
Experiment
• Voltage output
of lemon &
potato batteries
• How time affects
the battery’s
effectiveness
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Physics
Data Presentation
Experiment I
day 1
day 2
lemon
voltage ± 0.001V
lemon
Voltage ± 0.001V
1
0.985
1
0.993
2
0.990
2
0.951
3
0.973
3
0.989
4
1.000
4
0.963
5
1.008
5
0.950
Average
0.991
Average
0.969
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Physics
Data Presentation
Potato
Voltage ± 0.001V
Potato
Voltage ± 0.001V
#1
0.808
#1
0.743
#2
0.895
#2
0.814
#3
0.928
#3
0.794
#4
0.938
#4
0.940
#5
0.992
#5
0.857
Average
0.912
Average
0.830
Physics
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Conclusion
• Lemon batteries’ potential difference
(voltage output) are relatively larger
• Average potential difference (voltage output)
of the batteries decrease as time increases
Chemistry
How do lemon batteries create electricity?
Oxidation-reduction (redox)
• These reactions involve the transfer of
electrons between substances.
• Redox reactions release energy, and this
energy can be used to do work if the
reactions take place in a voltaic cell.
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Chemistry
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Standard Electrode Potentials
• The cell potential is a measure of the difference
between the two electrode potentials.
• The standard electrode potentials, Eo , in aqueous
solutions of Cu and Al are +0.34 and –1.66 V with
reference to hydrogen H.
• The cell voltage of the ”lemon battery” is the
“difference”,
U = (+0.34) – (-1.66) = 2 V.
Chemistry
★
Experiment
To investigate the relationship between the
acidity of the lemon and its voltage
output.
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Chemistry
Data Presentation
Experiment II
China
1
2
3
4
5
6
7
8
9
10
Average
Voltage
± 0.001 V
0.961
0.991
0.505
0.947
0.964
0.976
0.969
0.940
0.957
0.947
0.916
pH ± 0.1
Thailand
3.0
2.9
3.0
3.0
3.3
3.0
3.1
3.2
3.1
3.1
3.1
1
2
3
4
5
Average
Voltage
± 0.001 V
0.948
0.976
0.517
0.947
0.955
0.869
pH ± 0.1
2.8
2.8
2.9
2.9
2.9
2.9
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Chemistry
Data Presentation
Voltage vs. pH level Graph (corrected)
1.000
y = -0.0207x + 1.0222
R² = 0.0436
Voltage (V)
0.990
0.980
0.970
0.960
0.950
0.940
0.930
2.7
2.8
2.9
3.0
3.1
pH level
3.2
3.3
3.4
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Chemistry
Data Presentation
Voltage vs. pH level Graph
1.100
Voltage (V)
1.000
0.900
0.800
0.700
0.600
0.500
0.400
2.7
2.8
2.9
3.0
3.1
pH level
3.2
3.3
3.4
Chemistry
Conclusion
• UNABLE TO PROVE: Linear relationship
between voltage and acidity
• The conditions of the electrodes will
affect the voltage of the battery
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Biology
Experiment
To investigate the
geographic origins & mass
of the lemons.
Also the relationship of the
mass of lemon with its
voltage output.
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Biology
Data Presentation
Lemons from the USA
Mass
± 0.1g
Voltage
± 0.001 V
pH ± 0.1
1
164.13 g
0.907
3.0
2
179.75 g
0.946
2.9
3
155.31 g
0.914
3.0
4
173.60 g
0.906
3.0
Average
168.20 g
0.918
3.0
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Biology
Data Presentation
Lemons from China
Mass
± 0.1g
Voltage
± 0.001V
pH ± 0.1
1
109.82 g
0.969
3.1
2
115.83 g
0.940
3.2
3
110.44 g
0.957
3.1
4
100.17 g
0.947
3.1
Average
109.07 g
0.953
3.1
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Biology
Data Presentation
pH level vs. Mass
3.25
3.20
3.15
pH level
3.10
3.05
3.00
2.95
2.90
2.85
90.00
110.00
130.00
150.00
Mass (g)
170.00
190.00
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Biology
Data Presentation
Voltage vs. Mass
0.98
0.97
voltage (V)
0.96
0.95
0.94
0.93
0.92
0.91
0.9
90.00
110.00
130.00
150.00
Mass (g)
170.00
190.00
Biology
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Conclusion
• Both sets of data are randomly scattered
• Mass does not effect the voltage output of
the lemons
Conclusion and Evaluation
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Physics
Statistic values
20W light bulb
– 2.5 mg of coal (1 second)
•
•
•
•
– 2.5 kg of coal (11.5 days) cost: 2.5 RMB
108 lemons can provide the amount of voltage to
power 27 LED
The light energy given out by 27 LEDs equals to
120W light bulb
234 lemons can provide the amount of voltage to
power 120W light bulb
108 lemons (from mainland China) cost 216 RMB
Conclusion and Evaluation
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Physics
• Effectiveness of lemon batteries
– Individually and in groups
Lemon battery
Voltage ± 0.1V
1
2
3
0.9
0.9
0.7
2.5
Total voltage
• Time factor:
– Lemons biodegrade
Voltage ± 0.1V
Series of
batteries
2.1
Conclusion and Evaluation
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Chemistry
• Effects of electrodes on the lemon battery
- Surface oxidation
- Electrochemistry potential
Substance
Standard electrode potential
Lithium
﹣3.04
Magnesium
﹣2.37
Aluminum
﹣1.66
Zinc
﹣0.76
Iron
﹣0.44
Copper
＋0.34
Silver
＋0.80
Conclusion and Evaluation
Chemistry
• Economic costs for the electrodes
Metals
Cost (RMB per ton)
Magnesium
15.4 thousand
Aluminum
15.3 thousand
Copper (electrolyze)
59.0 thousand
Zinc
16.4 thousand
• Effects of acid in lemon on the electrodes
- Corrosion of metal
• Requirements for the redox reaction
- Must be electrically connected
- Could be provided by just the lemon juice
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Conclusion and Evaluation
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Biology
• Lemons can be genetically altered to become smaller in size
therefore more space efficient
• lemons are only able to bear fruit year round when grown in
mild climate
• Transportation of lemons
• Areas to mass produce lemons
1. Building Greenhouses
2. Opening more areas for plantation
3. Not enough space
• Effect of mass production of lemons on other plantation
• Use of water
Conclusion and Evaluation
Biology
• Not enough lemons  affected accuracy of data
1. Variety of sizes
2. Variety of locations
• Time
1. Grow lemons under different conditions
(e.g. soil pH)
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