Hydrogen Definition and 1000 Threads

Hydrogen is the chemical element with the symbol H and atomic number 1. With a standard atomic weight of 1.008, hydrogen is the lightest element in the periodic table. Hydrogen is the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass. Non-remnant stars are mainly composed of hydrogen in the plasma state. The most common isotope of hydrogen, termed protium (name rarely used, symbol 1H), has one proton and no neutrons.
The universal emergence of atomic hydrogen first occurred during the recombination epoch (Big Bang). At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, non-toxic, nonmetallic, highly combustible diatomic gas with the molecular formula H2. Since hydrogen readily forms covalent compounds with most nonmetallic elements, most of the hydrogen on Earth exists in molecular forms such as water or organic compounds. Hydrogen plays a particularly important role in acid–base reactions because most acid-base reactions involve the exchange of protons between soluble molecules. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) when it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H+. The hydrogen cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds are always more complex. As the only neutral atom for which the Schrödinger equation can be solved analytically, study of the energetics and bonding of the hydrogen atom has played a key role in the development of quantum mechanics.
Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, the property for which it was later named: in Greek, hydrogen means "water-former".
Industrial production is mainly from steam reforming natural gas, and less often from more energy-intensive methods such as the electrolysis of water. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market. Hydrogen is problematic in metallurgy because it can embrittle many metals, complicating the design of pipelines and storage tanks.

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  1. G

    Hydrogen atom at finitine temperature

    hi i asked myself, is it correct to use the ordinary partition function and cut it off at some value to describe the atom at some finite temperature? or is there a better way to do this calculation? and if i evaluate the partition function for let me say n=2. does this mean, that the...
  2. K

    Hydrogen atom expectation of r^2 check

    I haven't posted any of my working for this as I only want to check my answer. Q. For a hydrogen atom with n=2, l=1, m=0 calculate <r^2> My answer = 0.75 * a^2 where a is the bhor radius. Am I right?
  3. D

    Momentum representation of hydrogen atom

    Homework Statement I need to calculate the probability distribution of 1s and 2p state of hydrogen atom in momentum and in coordinate representations. I have calculated the wave function in coordinate representation, and the dilemma is, do I simply do the Fourier transform for given wave...
  4. S

    Hydrogen Atom's Energy Levels-True/False

    Homework Statement Which of the following statements are true about the hydrogen atom's energy levels? the ground state (n = 1) energy is -13.6 eV TRUE the wavelength of a photon emitted from the n=3 to n=2 transition is longer than that emitted for the n=4 to n=3 transition FALSE...
  5. M

    Converting a Small Engine to Run on Hydrogen: Challenges & Questions

    For a Science Expo project I will be converting a small engine to run off hydrogen. I have in mind a cheap four stroke water pump. My father said he is willing to let us use...
  6. D

    From hydrochloric acid to hydrogen chloride

    It is easy to produce hydochloric acid from hydrogen chloride by simply dissolving it into water or even with room humidity, it is sufficiently to form dense white fumes of hydrochloric acid. But is it possible to produce or extract hydrogen chloride from hydrochloric acid? (At best, a cheap...
  7. B

    Quantum Numbers for Hydrogen Atom Electron

    Homework Statement Define the quantum numbers required to specify the state of an electron in hydrogen. The spatial part of the wave-function describing a particular hydrogen atom has no angular dependence. Give the values of all the angular momentum quantum numbers for the electron...
  8. B

    Hydrogen Atom -> Uncertainty Principle

    Hydrogen Atom ---> Uncertainty Principle Hey guys, I'm having some trouble with this one. [PLAIN]http://img849.imageshack.us/img849/2039/physhw.jpg How do I get started?
  9. T

    Required mass for hydrogen burning in stars

    Hello all! I have to calculate the required mass to ignite the PP chain when the given temperature is 4*10^6K and \mu=0.62. (I know the answer is about 8% from the sun's mass)… I don't know exactly how to do it :-/ I know that (R/Rsun)=(M/Msun)^(3/7), The energy per nucleon in PP process is...
  10. J

    Why are fission uranium bombs more used than fusion hydrogen bombs?

    I keeps seeing news about iran making uranium and everybody is using nuclear fission bombs instead of nuclear fusion. Hydrogen bombs are much more powerful because they use fusion, but still all countries that have nuclear weapons use uranium fission bombs, Why? What advantage does fission...
  11. M

    Modifying a Small Engine to Run on Hydrogen - Need Help!

    For an upcomming science expo my friend and I are attempting to modify a small engine (such as found in a brush cutter) to run of hydrogen. We do however have a number of concerns and was wondering if anyone would be able to help. Firstly should we run it off tanked hydrogen and air or should...
  12. baywax

    Is there a way to replace nuclear power with a (big) hydrogen fuel cell

    Could one really big hydrogen fuel cell battery replace a nuclear reactor in providing power to millions of people? This may end up being a safer option for generating power.
  13. X

    Why aren't we using Hydrogen as a source of fuel for cars?

    What I mean by the title is, why isn't it more popular? (I know there DO exist some hydrogen powered cars.) To me it just makes sense to use hydrogen. It is very explosive and it's byproduct is water! The only draw back I can see is storing the gas in the vehicle to be used. Can anyone...
  14. C

    Hydrogen Emission Spectra Wavelength

    Homework Statement A transmission diffraction grating with 528 lines/mm is used to study the line spectrum of the light produced by a hydrogen discharge tube. The grating is 1.3m from the source (behind a hole in the center of a meter stick). An observer sees the first-order red line at a...
  15. A

    (n=3, l=2, j=5/2) -> (n=2, l=1, j=1/2) hydrogen transition?

    Hi, I have a doubt about the fine structure of the hydrogenic atoms. In the section 3.2 of the book Physics of Atoms and Molecules by Bransden & Joachain says: Since the electric dipole operator \mathbf{D} = -e\mathbf{r} does not depend on the spin, the selection rule derived in Chapter 4...
  16. S

    Where is the Classically Forbidden Region for a Ground-State Hydrogen Atom?

    Any region of space in which the kinetic energy T of a particle would become negative is forbidden for classical motion. For a hydrogen atom in the ground state: (a) find the classically forbidden region (b) using the ground-state wave function \psi100(r), calculate the probability of finding...
  17. S

    Hydrogen atom wave function Help

    Consider a hydrogen atom whose wave function is at t=0 is the following superposition of energy eigenfunctions nlm(r) (r, t=0) = *[2100(r) -3200(r) +322(r) What is the probability of finding the system in the ground state (100? in the state (200)? in the state (322)? In another energy...
  18. S

    Calculating Probabilities and Expectation Values for Hydrogen Atom Wave Function

    Consider a hydrogen atom whose wave function is at t=0 is the following superposition of energy eigenfunctions \psinlm(r) \Psi(r, t=0) = \frac{1}{\sqrt{14}} *[2\psi100(r) -3\psi200(r) +\psi322(r) What is the probability of finding the system in the ground state (100? in the state (200)? in...
  19. S

    Electric potential of hydrogen molecular ion

    Homework Statement The hydrogen molecular ion , with one electron and two protons, is the simplest molecule. The equilibrium spacing between the protons is 0.11nm . Suppose the electron is at the midpoint between the protons and moving at 1.5 m/s perpendicular to a line between the protons...
  20. P

    Muon g-2 and Muonic hydrogen anomalies

    What's the dominating opinion about the issue that muon g-2 deviates from the standard model? Is this generally considered as experimental inaccuracy, incompetent theoretical calculation, or genuinely beyond the standard model? On a related front, I'd like to ask about the experimental...
  21. Topher925

    Detection of hydrogen peroxide in water

    Is there any relatively not difficult way to detect if hydrogen peroxide (H2O2) is present in pure water? I can think of a few obvious ways for high concentrations but what about concentrations of around 0.001mol%? Is there a way of detecting concentrations that small or smaller?
  22. T

    Ordinary chlorine vs hydrogen peroxide as a bleach

    I've bought some of the stuff recently mainly to replace normal household chlorine bleach. It fizzes when it's destroying germs, and unlike ordinary bleach, doesn't smell a fraction as bad (and is great as a mouthwash or completely removing pet smells etc.). Unlike chlorine bleach, it also...
  23. M

    Number of moles of hydrogen gas in the cylinder

    Homework Statement A gas cylinder contains 4.00 x 10^4 cm^3 of hydrogen at a pressure of 2.50 x 10^7 Pa and a temperature of 290 K. The cylinder is to be used to fill balloons. Each balloon, when filled, contains 7.24 x 10^3 cm^3 of hydrogen at a pressure of 1.85 x 10^5 Pa and a temperature...
  24. Vectronix

    Basic questions about hydrogen and hydrogen gas

    It's been a while since I studied chemistry. Why are hydrogen atoms always attracted to other hydrogen atoms and then form H2 (hydrogen gas)? What are the differences with oxygen binding to itself and the formation of H2?
  25. K

    Why Does Hydrogen Emit a Line Spectrum Instead of a Continuous Spectrum?

    Homework Statement My Chemistry book says: "Before reading further about the details of Bohr's model, speculate as to how they explain the fact that hydrogen gas emits a line spectrum rather than a continuous spectrum." Homework Equations The Rydberg Equation, though I suppose this is more...
  26. A

    Positronium, Hydrogen, Schrodinger Equation

    I have been studying QM and am interested in keeping to the non-relativistic theory for now. In many experiments of crossed gamma rays in the vicinity of a massive particle (or nucleus), pair generation of an electron and its anti-particle the positron is well described. In some instances, the...
  27. A

    Fusion Reaction of Hydrogen and Deuterium into Helium

    Homework Statement In a fusion reaction, the nuclei of two atoms join to form a single atom of a different element. In such a reaction, a fraction of the rest energy of the original atoms is converted to kinetic energy of the reaction products. A fusion reaction that occurs in the Sun converts...
  28. A

    What happens to burned up hydrogen?

    What happens when hydrogen is burned up? Does it disappear? An element is defined as something that can not, in any way, be changed by a chemical reaction. But fire is a chemical reaction. What happens when hydrogen catches fire?
  29. E

    Is the hydrogen molecule bonding really covalent?

    Hi there! I'm studying the hydrogen molecule. According to the MO technique I start from one-electron molecular orbitals to construct the wave function of the entire molecule. Afa hydrogen is concerned, I can construct two ^1\Sigma_g orbitals: \Phi_A=\Phi_g(1)\Phi_g(2)\chi_{0,0}...
  30. B

    Hydrogen Spectra: Electron Jumping & Emitting Lines

    Hello, When electron is excited in single atom hydrogen, it jumps to a certain level, let's say from 1 to 4. My question here is, does this electron jump back immediately to 1 or does it cascade itself down to 3 to 2 to 1. and emits 3 lines instead of just 1. Thanks
  31. C

    Is the Spontaneous Reaction of Hydrogen and Oxygen Dependent on Temperature?

    Hydrogen and Oxygen "burn" Does anyone know the temperature at which this reaction becomes spontaneous? 2H2O--> 2H2 + O2 I can't find my book with thermodynamic data, but it should be cake for you guys. Thanks.
  32. S

    Hydrogen Propellant: Can it Power an Engine?

    Can hydrogen be burned and used to drive an engine?
  33. A

    Dynamics of electron in Bohr Hydrogen atom

    1. Consider Bohr Hydrogen atom with counter-clockwise electron orbit in the xy plane with intial position r(0)=-a0y. The angular frequency of the orbit is w. Derive an expression for the position of electron at a later time t, r(t) in terms of a0 , w, t, x, and y. Homework Equations...
  34. C

    Understanding Probability Densities for Hydrogen Wave Functions

    Homework Statement The problem, along with a solution, is attached as an image file. Homework Equations The Attempt at a Solution I have done the problem which was very straight forward. One simply had to look up the Rn,l and then plug in the appropriate quantum numbers. Since for...
  35. A

    Real Hydrogen Atom: Exploring Electron Energy Effects

    I've heard that the hydrogen atom that we originally learn about in QM that deals with the Coulomb force is an incomplete description. I'm having trouble understanding all of these effects. When describing the electron energy of the real Hydrogen atom, how do things like the zeeman effect...
  36. M

    Relation between kinetic energy and temperature for hydrogen

    Hello I have a question about the relationship between kinetic energy and temperature for the hydrogen. In my professor's note, there is written that: (1/2)m*(v^2) = (1/2)*K*T where m is the mass, K the costant and T the temperature in Kelvin. My doubt is in the fact that on...
  37. C

    Hydrogen atom with discrete nonlinear Schrödinger equation

    Hi everyone, How can I solve hydrogen atom with discrete nonlinear schrödinger equation? Could you help me with the mathematics of that, please?
  38. D

    Why is there still mostly hydrogen in pop I and II stars?

    I've heard in the past something along the lines of "every atom in your body came from an exploding supernova". Yet, I can't see how that could be true when there is still such an abundance of hydrogen. Wouldn't any hydrogen in a star prevent it from reaching supernova stage? Assuming...
  39. X

    Balmer series for atomic hydrogen lie

    Homework Statement The first few lines of the Balmer series for atomic hydrogen lie at the wavelengths λ = 656.46, 486.27, 434.17, 410.29nm, ... Find a value for RH, the Rydberg constant for hydrogen. The ionization energy I is the minimum energy required to remove the electron. Find it from...
  40. S

    Calculate Volume of Hydrogen Needed to Hydrogenate 50g Trans-Carveol

    Homework Statement Calculate the volume required to hydrogenate 50g of trans-carveol at STP. Homework Equations PV=nRT m=152g The Attempt at a Solution I think I might have this one but just for clarification if I'm missing something. The amount of moles is 0.329 using the amount...
  41. D

    <r> and <V(r)> in the Hydrogen Atom.

    Hi. I'm a 3rd year undergraduate studying Applied Physics and I'm having some trouble with a problem concerning the Hydrogen Atom. This is my first post so please forgive the sloppy equations. Not really used to writing this stuff out without an equation editor handy! Anyway, the...
  42. T

    Intergalactic space travel and hydrogen blasting

    Intergalactic space travel and hydrogen "blasting" To travel by spaceship to Andromeda (2.5 million light years) within a life time (say 50 years) you would have to travel with a much greater Lorentz factor than LHC protons, 50000 versus 7500. The LHC supposedly can melt a metric ton of copper...
  43. N

    Radiation that interacts with hydrogen

    Hi there, Is hydrogen gas transparent to most radiation or is there a wavelength that interacts with hydrogen? I'm asking because I want to know if it's possible to "push" hydrogen in a vacuum with some kind of photons.
  44. L

    Tokamak using elctrons instead of hydrogen nuclei

    Q.) What would happen if a *reverse-Tokamak* was created, thus reversing the electromagnets to a negative charge and repelling electrons into each other instead of fusing hydrogen nuclei, what approximate temperature would need to be used and would it work? If so what would occur?
  45. H

    The 6 hydrogen spectral line series'

    I noticed that the hydrogen spectral lines are grouped into 6 series and given a value for n. I also noticed that each series was named after its discoverer but "coincidentally?" falls into a specific region of the EM spectrum so the Lyman series (n=1) of lines are all in the UV region, the...
  46. G

    What is the mean speed of hydrogen atoms at 50K?

    Homework Statement Dear all, I have to calculate the mean speed of hydrogen atoms, at temperature of 50K. Homework Equations Of course: <v>=\sqrt{\frac{8k_BT}{\pi m}} The Attempt at a Solution However, when I attempt to calculate it, m=\frac{2}{6.022x10^{23}} k_B=1.3807x10^{-23}...
  47. P

    Unraveling Weak Field Stark Effect in Hydrogen

    Homework Statement Considering the n = 2 states of hydrogen: In the absense of an external field, the four j = 1/2 states are degenerate. Using degenerate pertubation theory, I am supposed to show that for a very weak field the Stark effect shifts the energy levels by \mp \sqrt{3}a_0 e...
  48. F

    What does it take for hydrogen to form from protons and electrons?

    Hi What does it take for hydrogen to form from protons and electrons? I have searched quite a bit and the only information that I have so far is from this webpage http://www.Newton.dep.anl.gov/askasci/phy00/phy00843.htm from the webpage ------------------------------ To form a hydrogen...
  49. A

    Why Are Absorption Lines Observed Only in the Lyman Series for Hydrogen?

    When white radiation is passed through a sample of hydrogen gas(atoms assumed actually) why are absorption lines observed in Lyman series only? The corresponding photon energy range for visible light(380-780nm) are 1.59-3.27eV which should cause transitions of electrons in the first excited...
  50. X

    Comparing Power Generation Potentials of Hydrogen and Xenon

    Generally the working fluids in a power generating system is either water (steam) or air. This I imagine is because they are widely available fluids. The specific heats of these ranging from some 1 - 2 kJ/kg-K. For the sake of argument, let's assume that hydrogen or xenon are equally...
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