questions (1 Viewer)

[Aerlinn]

1. An experimental source of power for a heart pacemaker involves implanting a zinc electrode and a platinum electrode into tissues in the body. Oxygen present in body fluids is reduced at the platinum electrode. Before this method of power generation if used, what further investigations would be necessary?
2. Supposed a chemist had an aqueous solution of potassium chloride. How might the chemist produce elemental potassium from the solution?
-it doesn't make much sense...
3. Explain why a fuel cell could reduce greenhouse emissions.

 

[xiao1985]

1) ohhh heaps of stuff you could talk about.... what's the product of reduction of oxygen? also, platinum complexes are known cytotoxins (yes, what i'm dealing with now), is it really safe to have platinum metal in your body? (it's a question, not a rhetorical one)

2) ie we have K+ and Cl-... how do we produce K (s)

3) think this way: fuel cells are more efficient than normal lead acid, zinc etc. why might more efficient harness of energy reduce greenhouse emission?

 

[beentherdunthat]

3. Explain why a fuel cell could reduce greenhouse emissions.

I can explain this one. You see the fuel cell is different than most Galvanic cells because its reactants are in the form of GASES. In particular, hydrogen gas and oxygen gas. The fuel cell works by producing electricity at a constant rate, as reactants are fed into it and products are removed.

The overall reaction would be, essentially, the combustion of hydrogen gas

Hence;

h2 (g) + o2 (g) ----> h20 (g)

This process is preferable, and produces little or no environmental pollution because it is only producing a water as a product, which is actually a good thing. Hence, it is not releasing various pollutants that would contribute to the greenhouse effect. Therefore, it would reduce greenhouse emissions.

A negative obstacle is that the auxilliary systems that feed reactants into the cell and remove them are quite expensive...
Fuel cells are conventionally used in spacecraft and apollo aircrafts.
The reactants are stored as liquids until they need to be used...

I hope that explains things simply

 

[Aerlinn]

1. Are potassium complexes dangerous? I have no clue... heh
2. That's why it doesnt make sense. If it's aqueous solution, we get a high voltage running, wouldnt Cl-(aq) react with water forming H2 and Cl2 or something? Or K+(aq) might also be reacting to make K(s) at the same time... I'm not sure about these voltage things
3. Thanks, beentherdunthat, that explained it perfectly ^^

 

[xiao1985]

but my friend, the product, water, is a (in fact, the biggest) green house gas. It will be true to say however, that on the green house gas emitted per energy generated scale, fuel cell is much more greenhouse friendly, as the conversion between chemical potential energy to electrical energy is near 100% efficient, as contrasting to coal powered stations, which has efficiency much much lower.

- potassium complexes: depends on potassium what.... potassium ion itself is not really harmful, unless consumed in large quantity, but the counter anion maybe harmful..

- aq => higher voltage as contrasting to what?