BUT, for B Hydrogen has to come from somewhere. Generally energy is used to separate Hydrogen from water. The source of that energy determines how clean the entire process is. If you burn a bunch of coal in order to make a little hydrogen, then it is not really clean at all.
A clarification should be made for D as well. Burning fossil fuels, if done efficiently, will produce only CO2 and H2O. That would be ideal. But the less efficient and less clean the process is, the more compounds that are produced that are not CO2 and H2O. These other compounds are what cause acid rain and smog. CO2 does not cause either.
A further clarification for C must also be made. Better is a very relative term. There are many ways of producing energy that makes zero CO2, but they may not very efficient or produce enough power, or produce the power in a consistent manner.
Who is writing these questions for you? Some grade school teacher.
a. Define Global Warming.
b. Define Environmentally friendly.
c. 'Better'? What do you mean by better? Better for whom?
d. It has been proven by core samples that the earth had acid rain in Christ's time. Did he have an SUV? Did his sandals use lead free gasoline?
Notice that all the greenies answered your ambiguous questions. Some of these call themselves a scientist. No true scientist would or could answer those proven ambiguous question. Science is exact and propaganda is not.
The answer they're looking for is: e All of these are true.
However, there is no "free" hydrogen on earth.
All of it is contained in molecular form, from water, to natural gas, to oil, to any number of compounds.
Isolating the hydrogen from those compounds always produces CO2, so that while just burning hydrogen is environmentally friendly, the process that is used to create the hydrogen in the first place is not.
e All of these are true.
Production of hydrogen requires energy. If the energy comes from electricity, the electricity comes from nuclear power or a renewable source, and the hydrogen comes from water, no carbon dioxide is released.
http://en.wikipedia.org/wiki/Electrolysi...
(f) If you had stayed awake 20% of the time in class, you would know that the answer is (e).
E- all of these are true
(f) none of the above.
e.
a The burning of fossil fuels contributes to global warming.
b Cars that run on hydrogen fuel cells are environmentally friendly.
c The more energy produced per kg of CO2 produced, the better the fuel.
d Acid rain is one of the problems associated with the combustion of fossil fuels.
e All of these are true.
