Finally, a breakthrough on how to harness solar power

NEWKERALA.COM ^ | Aug 1, 2008 | NA

[r9etb]

The solar energy has to be converted into electricity first, it appears.

True enough, although the tie-in to photosynthesis suggests that at some point this may not be a strict constraint.

What they're talking about here, though, is a way to store energy once it's generated ... or to convert it to something more portable (such as, for use in a fuel cell).

[r9etb]

Second, does a fuel cell burn the oxygen and hydrogen to produce the energy that runs some kind of generator? Yes, reforming the stuff back into two molecules of water and releasing the energy in those chemical bonds. Hydrogen likes to be in the oxidized state of water. Oxygen likes to be reduced state of water. In chemistry they are called reduction - oxidation, aka redox, reactions.

More specifically, fuel cells produce electricity from the recombination of hydrogen and oxygen. For example, the Space Shuttle gets all of its electrical power from fuel cells.

[xzins]

Do you lose mass of water over time? For example, if a liter is converted into H’s and O’s, and then you burn it, and it reforms back into 2 molecules of water, will you end up with a liter of water or will you have less?

[neverdem]

Do you lose mass of water over time? For example, if a liter is converted into H’s and O’s, and then you burn it, and it reforms back into 2 molecules of water, will you end up with a liter of water or will you have less?

In chemical reactions, you always have conservation of mass. Nuclear reactions are different, but you still have to have a total conservation of mass and energy even if the energy is lost as heat, etc. The loss of mass is converted to energy.

[xzins]

Are you saying that you end up with less than a liter of water because of the loss to energy?

[neverdem]

Are you saying that you end up with less than a liter of water because of the loss to energy?

No, not in just chemical reactions. There is no loss of mass in chemical reactions. The energy is in the chemical bonds that is released in redox reactions. If there are any more questions, I want to get paid. Wikipedia is a decent source for non-political stuff, but I like Answer.com, Ask, etc. Maybe I linked "How Stuff Works" in comment# 1 about solar power.