Tinton
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Group IV--Urea, Ammonia, and Hydrogen.
I have to complete a project known as "Group 4" at my school. Those of you that have heard of IB might know what it is.
Basically, 3 students choose hypotheses in their field (Environmental chemistry, Biology, Chemistry) that fit under a collective research question,
which then fits under a democratically chosen "Topic area" for our class as a whole.
Last year our overarching class topic was pollution. My group's research question was "how effectively does vibrio phosphoreum indicate water
pollution hazards."
For that research question, the biology student measured the light produced from the bacteria in different polluted environments, and I measured the
oxyluciferin content of the bacteria in different environments, which corresponded to its light production.
The environmental chemistry student pretty much made up results for a B.S. topic, which is sadly what most students do.
This year, I'm having a bit of trouble. Our research question is now uncertain because of the dropping out of one of our group members. I am now stuck
with a research question which ties my hypothesis to hydrogen. I can still change the research question, but due to the nature of my partners'
hypotheses, it must relate to hydrogen in some way.
I've been working with hydrolyzing urea to produce ammonia, as well as electrolyzing ammonia to produce hydrogen.
The main problem with using these concepts for my group 4 project is the creation of variables, and thus, a hypothesis. I don't really know what to
differ in the experiment that would somewhat resemble "original research".
Our school doesn't have enough metals to test the efficiency of different electrodes. We don't have accurate enough calorimeters to decide the total
enthalpy change of the system.
I was thinking about coupling the ammonia production and hydrogen production and electrolyzing the urea/ammonia solution. I've read articles in which
nickel electrodes have successfully been used to electrolyze urea and produce hydrogen. My hypothesis might compare the production efficiency of just
ammonia, and then urea and ammonia.
Long story short, I need help, or at least brainstorming fellows to help come up with good hypothesis. Or criticisms of my current resemblance of a
hypothesis.
Any thoughts are appreciated.
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bbartlog
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I'm not sure I understand the possible scope. However, you mention that the efficiency of different electrodes would be a possible topic if you had
enough metals. If electrolysis efficiency (or balance of products) would be a valid area of inquiry, then I would suggest looking at some of the other
variables that can influence it, such as
- current density (if you have a decent bench power supply, i.e. one that allows you to set a constant current level and reasonably fine control)
- voltage
- solution pH
- temperature
- mixing and/or cell division by membrane
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not_important
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bbartlog has good suggestions there. It is easy to measure the cell voltage at different current levels, which gives you the power consumed.
Measuring the efficiency is more difficult, as several of the potential products are fairly soluble in water you can't just collect the gas generated
in a specified interval.
Varying the temperature gives you two variables, electrolyte concentration is a third. You could vary pH, but effects on concentrations of the active
species have to be considered.
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Tinton
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To put the scope simply, I must design a chemistry experiment that at least tangentially relates to hydrogen production.
Unfortunately, our school has a constricting lack of chemical availability. So I think electrode experimentation is out of the question at this point.
I had considered those variables, but the outcomes should be calcuable via the nernst equation. IB might recognize that as original research, but I
plan to use this as an example lab for my college appplication, which may not recognize an easily theorized conclusion as original.
However, I may end up using voltage and current as variables and measuring overpotential of different solutions.
My hypothesis would be something similar to "coupling urea hydrolysis with ammonia electrolysis will decrease the overpotential of the cell."
Thoughts?
[Edited on 9-12-2009 by Tinton]
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Tinton
Harmless
Posts: 15
Registered: 16-12-2007
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Mood: homework laden
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Update.
I think I'm going to head in the direction of "hydrogen enhanced ammonia."
Burning ammonia, bubbling the exhaust gas through water, and measuring the proportional NOx through the pH of the water. Then burning ammonia and
hydrogen together, and measuring the pH of the exhaust solution.
My hypothesis will probably be something like, "ammonia, when combusted with a significant percentage of hydrogen gas, will produce fewer nitrogen
oxides."
This should be pretty easy, because ammonia's oxidation is used to make nitric acid.
Anyway, I just spent 5 hours in my lab working on it, my back hurts, and I can't think straight. Thanks for your suggestions, it really helped the
brainstorming process.
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