science question please help?

Question

I just want to know how fuel cells work as I am doing research on it. Here is what I know.
I know that a fuel cell uses hydrogen to convert it into a form of electricity that the cars can use. There are exothermic reactions that release energy and endothermic reactions that absorb energy. Our goal is to separate the hydrogen from the water. so set up 2 equations
1. Water- 2H+O-energy
2. Water-2H+O+energy
we want to get energy and not to make it so we go for the first one right. I am a bit lose so please help

Answer 1

The first equation is correct. The second is wrong.

2 H2O + energy --> 2H2 + O2

Splitting water in endothermic.

You need to spend energy to break up the water to make your hydrogen fuel, so you can later do the reaction in reverse and get that energy back (that reaction is exothermic). There's no such thing as a free lunch here.

Answer 2

Fuel cells are in fact oxidation / reduction reactions where electrical energy is produced. The electrical energy is then consumed by an electric motor or other device to do work.

Conventional internal combustion engines are about 35% efficient whereas fuel cells are about 90% efficient - about 3 times better and this is a remarkable improvement.

People have been working on fuel cells for over 40 years and to date few economically practical units have materalized. With oil at its current price, economic practacality may be near.

Fuel cells are not exclussively fueled by hydrogen. The advantage of hydrogen is that the product made is water, which is an environmentally friendly product.

Hydrocarbon fuel cells produce water and carbon dioxide. Borane fuel cells produce water and diborontrioxide which is a solid and unattractive.

Fuel cells do not create hydrogen and oxygen from water. An electrolysis system does. In this system, water is broken down into hydrogen (H2) and oxygen (O2) with the application of electrical energy. The oxygen is not used as a fuel component as there is plenty of oxygen on earth; it is used in other applications.

Hydrogen, a very lightweight gas, is hard to contain and transport. It has a very low boiling point so it takes a lot of energy to compress it into a liquid. This makes hydrogen transportation a major challenge.

One interesting concept is to use react hydrogen with carbon dioxide in the air to make methanol, or methyl alcohol which is a liquid. This can be easily transported and used as an internal combustion engine motor fuel (with minor modification to today's gasoline engine) and used as a fuel cell fuel. Combustion products are water and carbon dioxide. Foes of carbon dioxide have no complaint here because the carbon dioxide produced in combustion originally was taken from the air so the net result is no change.

I suggest you learn how oxidation / reduction reactions occur as a starting point. It is way to lengthy to discuss herein. Start with high school chemistry texts - and perhaps look at introductory college chemistry texts after that.

Answer 3

I made a mistake, fuel cells are not inefficient, quite the oposite, what I meant was that their output is meger for what the avarage person would find useful.

Answer 4

Just Google fuel cells, and you will see all you want to know...

http://en.wikipedia.org/wiki/Fuel_cell

Ron.