2H + 20 -> 2H20 + Energy this has to do with hydorgen fuel cells and although im not adept in their whole concept im deeply interested in the development, and my question is if the only by-product of the reaction between Hydrogen and Oxygen is water and energy could that water then be recycled as the fuel source for that same fuel cell? Or does the law of conservation apply? Sorry if my terms are incorrect as I am only in Grade 10 science...
Yes it can be reused, but you have to put energy back into the water to break it into oxygen and hydrogen, it's the process of electrolysis.
In this equation 2H20 means you actually have 2 molecules of water, the components of which are 4 hydrogen atoms and 2 oxygen atoms. How did you double your hydrogen atoms AND have energy left over?
yes indeed but you have not answered my question. The 2 in front of that molecule means there are 2 molecules. If you look at all the components of those 2 molecules, there are 4 total hydrogens and 2 total oxygens. But you did not start with enough components to make that many
the equation would be correctly balanced by writing it this way: 2 H + 2 O = 2 H O + energy 2 2 2 I hope that comes out right. The law of conservation obviously applies always, thus as you can see the amount of atoms of each stay the same. So the answer to NileQueen's question is that you don't get more atoms, but I think that the energy comes from the electrons in the hydrogen (and probably in the oxygen too) collapsing into 'lower' energy states. I myself still have problems with the electron states and the definition of heat vs energy of matter. Its all kind of fuzzy. For example, can anyone explain how a molocule of hydrogen or oxygen can be moving so much quicker than water, yet be the same temperature (or truely even colder in a closed system after reacting) as water? Anyone?
I believe what nilequeen is talking about is there isn't enough atoms to beging with. The correct number of atoms should be the following (or any multiple of the following) 2H2 + O2 = 2H2O 2 hydrogen molecules (which are 2 hydrogens) + 1 oxygen molecule (which is 2 oxygen) = 2 water molecules (2 hydrogen and 1 oxygen for each water) Can you give an example? The kinetic energy of a particle is .5m*v^2 (.5*mass*velocity^2) mass of hydrogen = 1.00794 grams/mole mass of oxygen = 15.9994 grams/mole one molecule of hydrogen = 3.34725E-27 Kg one molecule of water = 2.991329E-26 Kg Now if they're both moving at 5m/s... The kinetic energy of the hydrogen molecule is 4.18406E-26 Joules. The kinetic energy of the water molecule is 3.73916148E-25 Joules. Water of course has a high kinetic energy(when they're traveling at the same speed) because it has a greater mass than hydrogen. For hydrogen to have the same kinetic energy as water(water traveling at 5m/s), the hydrogen must be traveling at 14.9471 m/s. So 1 mole of hydrogen molecules with an average velocity of 14.9471 m/s will have the same kinetic energy of 1 mole of water molecules that have an average velocity of 5 m/s. The hydrogen has to be traveling nearly 3 times as fast as the water to achieve the same kinetic energy.
to bring up the dreaded car analogy- if you take a VW bug, put it into second gear, and rev the engine to 5000 RPM's, how fast does the car go? if you take a BMW roadster, put it into second gear, and rev the engine to 5000 RPM's, how fast does the car go? without any hard numbers, I'd bet that the roadster would blow the bug away. smae energy input into different systems gives different output. to connect this to the discussion, two different molecules with the same amount of energy input (heat), will react in different ways. --as for fuel cells, the hydrogen oxygenation fuel cell is great in terms of output and polution. but look at the ingredients: H2 and O2. in order to get these molecules in quataties sufficient to run a car with this reaction, you start needing to deal with the liquid forms of these molecules (reeeaaly cold). very hard to handle, very dangerous if spilled directly on exposed flesh, and very energy expensive to keep in a liquid state, AFAIK. It's a hell of alot better than gasoline in the long term, but to convinse the general public to switch, it has to be easy. thanks orbie- that's a very well designed explination.
"without any hard numbers, I'd bet that the roadster would blow the bug away. smae energy input into different systems " Just to clarify, those RPMs are not units of energy. Therefore you would be putting a ton more energy in the BMW to make it go faster, it all depends on the torque of the engine, etc. So the analogy isn't a good one.
http://www.eurekalert.org/pub_releases/2003-03/vt-tto031703.php "Three types of water discovered in fuel cells" This article might be of some interest But they don't seem to be talking about isotopes...
