hydrogen or methane or helium
123408
Ozone and Hydrogen, I think, it has been 15 years since chemistry in University
357044
since the all of the valance orbitals are filled, helium is much more stable than hydrogen. therefore, i wont explode or catch on fire or anything dangerous
429271
Water is just a liquid gas isn't it? Hydrogen and Oxygen mixed makes water. That's how.
274431
Helium (from Greek Hêlios: god of the sun) is a chemical element; its atomic symbol is He. It is a colorless, odorless, tasteless, non-toxic, and nearly inert monatomic that heads the noble gas series in the periodic table. Its atomic number is 2 and its boiling and melting points are the lowest among the elements. It exists only as a gas except in extreme conditions. Extreme conditions are also needed to create the small handful of helium compounds, which are all unstable at standard temperature and pressure. Its most abundant stable isotope is helium-4 and it has a rare stable isotope, helium-3. The behavior of liquid helium-4's two different states—helium I and helium II—is important to researchers studying quantum mechanics (in particular the phenomenon of superfluidity) and those looking at the effects that near absolute zero temperatures have on matter (such as superconductivity).\n\nHelium is the second most abundant element in the known Universe and second lightest element in the periodic table. In the modern Universe almost all new helium is created as a result of the nuclear fusion of hydrogen in stars. On Earth it is created by the radioactive decay of much heavier elements (alpha particles are helium-4 nuclei produced by alpha-decay).\n\nEvidence of helium was first detected on August 18, 1868 as a bright yellow line with a wavelength of 587.49 nanometres in the spectrum of the chromosphere of the Sun, by French astronomer Pierre Janssen during a total solar eclipse in Guntur, India. This line was initially assumed to be sodium. On October 20 of the same year, English astronomer Norman Lockyer observed a yellow line in the solar spectrum, which he named the D3 line, for it was near the known D1 and D2 lines of sodium, and concluded that it was caused by an element in the Sun unknown on Earth. He and English chemist Edward Frankland named the element with the Greek word for the Sun, ἥλιος (helios).
205746
How exactly are you splitting the H from the O?   Under high pressure and spraying?  I don't see how that could possibly work.  Cold fusion also has a huge potential for cheap, clean, renewable energy.  But much like what you are talking about, it simply isn't possible with the current technology.  If splitting H and O was so cheap and simple it would be done all of the time.  Electrolysis works, but the energy input makes it unrealistic for creating liquid hydrogen as an energy source.  If you truely have a way to spit the H20 molecule cheaply and efficiently you'd already be a multi-billionaire.
259646
Munir is right.  H2 will behave most like an ideal gas in a condition with Highest temperature and lowest pressure, making your Choice 3.
250600
Avogadro's hypothesis states that all gases, under the same conditions of temperature and pressure have an equal number of molecules. Thus a given volume of Hydrogen will have just as many molecules as the same volume of Helium. \n\nBut Hydrogen is the first element in the periodic table with an atomic density of 0.08987 at 0 degrees C. Helium at the same temperature has an atomic density of 0.1785. \n\nSince all gases have an equal number of molecules in a given volume, the density of hydrogen will be lesser than Helium.\n\nPeace.
401379
both of these two above ^ are wrong \n\nthere would be no reaction.\nall you're doing when you heat something is giving it energy which  causes its atoms (if it's an element) to move faster, which will change it to a higher state of matter. The gas state is the highest state of matter and H2 is the gas state of hydrogen. Since it's alreay in the highest state of matter, nothing would happen \n\n\nit would not form 2H because hydrogen is diatomic \nHydrogen only exists as a hydrogen ion (H^1+) in solution.\nand it only exists as a single atom in a compund.\nHowever, If you burned hydrogen in the right proportions of oxygen then it would be explosive, but that is not the case. \nAnd it would not be exothermic because if it was, heat would be on the product side of the equation.
234529
As mentioned above, two hydrogen atoms are brought together under high temperature and pressure so that they "fuse" into one and create a Helium atom.  What is not mentioned is that the result of this fusing is the creation of a huge amount of energy.  The energy comes from the difference in mass between the two hydrogen atoms and the resulting helium atom which weighs less.  The mass dissappears and is converted into energy in the form of electromagnetic radiation and kenetic energy of various particals.
528510
oxygen atoms are larger than helium atoms.\nThe helium leaches out of the balloon quicker than the oxygen.
92015
The uses you have identified are using Helium because it is inert and will not chemicaly react with other elements, however, there are potential uses for Helium as fuel, contrary to the other answers. \n\nHelium 3 is considered to be an ideal potential fuel for fusion-reaction power plants. The energy equivalent of Helium 3 compared to steam coal (at $2.5/million BTU) is about $140 million per 100 kg. In other words, it is a quite valuable resource if we are eventually able to utilize fusion reactors. \n\nThe most interesting part of this is that the moon's surface rock contains helium of this light isotope in much higher concentrations than found on earth. It could become economical to obtain He 3 from the moon if we develop fusion reactors as an energy source.
413369
"Iodine, it is sublime". (Because it sublimates-goes directly from solid to a gas).\n\nGet an "A".
248717
1 Hydrogen 2 Helium 3 Lithium 4 Beryllium 5 Boron. 6 Carbon 7 Nitrogen 8 Oxygen 9 Fluorine 10 Neon
633241
Using two or three standard cylinders of helium mixed with air or CO2 as a tracer gas the generator can be tested, repaired and re-tested prior to being filled with hydrogen for operation.\n\nLeak testing of operational generators is easily accomplished using one a hydrogen detector. This test is performed in the same manner as the helium test and provides similar test sensitivity.
292060
space shuttle burns hydrogen. imagine you're standing under it when it launches. endothermic or exothermic?\n\ncorrect reaction formula was already given.
306979
probably carbon dioxide mostly
367077
Hydrogen is extremely flammable, helium is entirely inert. \n\nGoogle for "Hindenburg".  No one know for sure why it caught fire, but once it did the results were spectacular (in a bad way).  \n\nThe US controlled most of the world supply of helium and wasn't letting Germany have any of it, so they were forced to use hydrogen.\n\nAnd yes, you're right, both of those gases are lighter than air due to their low atomic weight.