Helium (from Greek: ἥλιος, romanized: helios, lit. 'sun') is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. Its boiling point is the lowest among all the elements. Helium is the second lightest and second most abundant element in the observable universe (hydrogen is the lightest and most abundant). It is present at about 24% of the total elemental mass, which is more than 12 times the mass of all the heavier elements combined. Its abundance is similar to this in both the Sun and in Jupiter. This is due to the very high nuclear binding energy (per nucleon) of helium-4, with respect to the next three elements after helium. This helium-4 binding energy also accounts for why it is a product of both nuclear fusion and radioactive decay. Most helium in the universe is helium-4, the vast majority of which was formed during the Big Bang. Large amounts of new helium are being created by nuclear fusion of hydrogen in stars.
Helium was first detected as an unknown, yellow spectral line signature in sunlight, during a solar eclipse in 1868 by Georges Rayet, Captain C. T. Haig, Norman R. Pogson, and Lieutenant John Herschel, and was subsequently confirmed by French astronomer, Jules Janssen. Janssen is often jointly credited with detecting the element, along with Norman Lockyer. Janssen recorded the helium spectral line during the solar eclipse of 1868, while Lockyer observed it from Britain. Lockyer was the first to propose that the line was due to a new element, which he named. The formal discovery of the element was made in 1895 by two Swedish chemists, Per Teodor Cleve and Nils Abraham Langlet, who found helium emanating from the uranium ore, cleveite, which is now not regarded as a separate mineral species but as a variety of uraninite. In 1903, large reserves of helium were found in natural gas fields in parts of the United States, which is by far the largest supplier of the gas today.
Liquid helium is used in cryogenics (its largest single use, absorbing about a quarter of production), particularly in the cooling of superconducting magnets, with the main commercial application being in MRI scanners. Helium's other industrial uses—as a pressurizing and purge gas, as a protective atmosphere for arc welding, and in processes such as growing crystals to make silicon wafers—account for half of the gas produced. A well-known but minor use is as a lifting gas in balloons and airships. As with any gas whose density differs from that of air, inhaling a small volume of helium temporarily changes the timbre and quality of the human voice. In scientific research, the behavior of the two fluid phases of helium-4 (helium I and helium II) is important to researchers studying quantum mechanics (in particular the property of superfluidity) and to those looking at the phenomena, such as superconductivity, produced in matter near absolute zero.
On Earth, it is relatively rare—5.2 ppm by volume in the atmosphere. Most terrestrial helium present today is created by the natural radioactive decay of heavy radioactive elements (thorium and uranium, although there are other examples), as the alpha particles emitted by such decays consist of helium-4 nuclei. This radiogenic helium is trapped with natural gas in concentrations as great as 7% by volume, from which it is extracted commercially by a low-temperature separation process called fractional distillation. Previously, terrestrial helium—a non-renewable resource because once released into the atmosphere, it promptly escapes into space—was thought to be in increasingly short supply. However, recent studies suggest that helium produced deep in the earth by radioactive decay can collect in natural gas reserves in larger than expected quantities, in some cases, having been released by volcanic activity.
A tank having a volume of .100 m^3 contains helium gas at 150 atm. How many ballons can the tank blow up if each filled balloon is a sphere of .300 m in diameter at an absolute pressure of 1.2 atm?
Here is what I have so far: Assuming no gas is lost to the atmosphere, n is constant. R is...
A hypothetical question:
Say that Newton's constant G is increased a bit during the period between weak interaction decoupling and the time when photodisintegration becomes ineffective, and the helium is formed. (I.e. during the period when neutrons just decay). Would that give a larger or...
I'm learning about charge right now and I have no idea how to start this one.. any help is appreciated.
A helium balloon has a charge of q = 5.5 x 10^-8. It rises vertically into the air. d = 600m. from the surface of the Earth to final position A. The electric field that normally exists in...
I am giving a presentation on helium 3 for a future energy source and i am looking for a way to describe (and compare) how much energy is released in a helium 3 reaction (D-T would be fine). some thing that would be clear to people who have no science background. (i.e. the amount of H-3 that...
yes this is an egg drop project once again, i had the idea to use helium balloons, but the problem is that the whole thing must fit in a grocery bag. only two balloons fit in a grocery bag! that can't carry very much! we can't use paracutes, otherwise we can do anything. i tried just now to cut...
I'm guessing this most likely has something some to do with Helium's superfluidity, but I'm still managing to draw a blank on what exactly stops it solidifying.
Any thoughts?
Helium gas is compressed form 1 atm and 25 degree C to a pressure of 10atm adiabatically. the lowest temp. of helium after compression is
i don't know how to start if anyone can give me hint to start the problem it would be a great things
thank you
waiting for your answer
i got the...
a 2.00 mol sample of helium gas at 300K and 0.400atm pressure is compressed isothermally to 1.20atm
Find the volume of the gas, work done on the gas and the energy transferred by heat
just wondering how to approach this question, and what formulae i hould use where?
The question gives a picture of a brayton cycle with temperature on the x-axis and pressure on the y-axis. It is for the monatomic gas, helium, and we are told that there are two moles. The diagram consists of two adiabatic processes and two isobaris processes. You are given two temparatures...
We have to to a report in our chemisty class on heating houses. One aspect is the window. Our teacher says that good windows are filled with argon becuase they have a high specific heat. but looking on the internet I seem to find the specific heat of argon to be about 520 J/kgC which is...
The density of helium gas at 0.0 degrees C is 0.179 kg/m^3. The temperature is then raised to 100.0 degrees C, but the pressure remains constant. Assuming that helium is an ideal gas, calculate the new density of the gas.
Ok, so far i figure that since P is constant, I would need to work...
Would someone mind (in simple terms if possible) explaining how at the beginning of the universe Hydrogen combined to give Helium; then then how Helium combined with deuterium to create the heavier elements?
I would just like to be more versed on this process...
Thanks for any help!
Is helium a better alternative then the current proposed fuels for fusion reactors?
http://www.space.com/scienceastronomy/helium3_000630.html
http://www.asi.org/adb/02/09/he3-intro.html
Hi,
It requires 79.0 eV to remove both electrons from He in the ground state. The energy to remove a single electron is 24.6 eV. What is the relationship between these two numbers?
Thanks.
In a superfluid a small volume of liquid can be considered to behave as a single particle.Does this mean that ,for example,one cm^3 of helium-4 atoms
has a total spin of 2?
a couple nights ago whilst my presleep thoughts wondered about, i came across a balloon filled with helium. in this thought, i saw the not uncommon sight of it floating up. then i wondered why it went up and not down or some arbitrary direction. i know helium is lighter than our oxygenic...
Stuck again with this "not so informational" astronomy book, and we need help with a question.
What produced the helium in the Suns atmosphere, Jupiters atmosphere, and the suns core?
:cry:
can anyone help us?
No, I'm not thinking of buying one/any, but how much does one cost?, any type. Plus, how much do the two commonmost types of helium in liquid form, and/or liquid nitrogen, cost per gallon? I know liquid nitrogen is cheaper... a lot.
...If I were to not buy in bulk.
1. Calculate the rms speeds at 20 degrees celcius of atoms of
helium (4u)?
2. The escapte speed from the surface of the Earth is 11.2 km/s. Find at what temp. the following gas (O2) have this value as the rms speed?
3. One mole of an ideal monatomic gas is heated from 0 degrees celcius...
Hi friends...
Sometime back, I encountered the Self Consistent Field Method in Quantum Mechanics, which is used to compute wave functions in complex atoms. The book I read this from is "Practical Inorganic Chemistry" by Clyde and Day. The method is explained through an argument about the...
Given: R=8.31451 J/(K*mol)
Two moles of helium gas initially at 187 K and 0.33 atm are compressed isothermally to 0.57 atm.
Find the final volume of the gas. Assume the helium to behave as an ideal gas. Answer in units of m^3.
I've tried this many many times and i keep getting 5.455...
sir,
i get the fllowing reply for my question 'can helium be changed to hydrogen'
'' Helium to Hydrogen requires energy input, for just the same reason that Hydrogen to Helium produces energy. The mass of four protons is greater than the mass of a Helium nucleus (alpha...
sir,
I have to questions,
1. is it possible to change the helium of the sun to hydrogen.
2. can laser stop the electromagnetic wave if laser is charged to the electromagnetic wave face to face.
soumya
I was looking at a http://chemlab.pc.maricopa.edu/periodic/isotopes.html and was wondering why the half-life was sometimes replaced with electron volts? There's an example from the table below:
Helium-6 806.7 milliseconds -> Lithium-6
Helium-7 160 KEV -> Helium-6...
I can't seem to figure this simple helium balloon problem out? I would really appreciate some help? Thanks!
Estimate the volume of a helium-filled balloon at STP if it is to lift a payload of 500 kg. The density of air is 1.29 kg/cubic meter and helium has a density of .178 kg/cubic meter...
This is a new launch plaform idea to assist Nasa in meeting it's extra-planetary goals.
It seems that a large helium-supported platform in the upper atmosphere could save a lot of launch energy and pollution.
The platform might be quite large, perhaps 0.5 to 2 km in diameter, and could be...
The two questions that were on my exam, to be honest, i didnt answer because I didnt understand it enough to do so. But I am willing to learn and be shown the way to a legit answer, so please don't immediately give me answers.
The questions are like this:
The density of air near the...
Does it matter if we use one wave function to describe both electrons of a helium atom, or we need to use one wave function for each? Is there any empirical evidence of the right way?
I was wondering if any of you guys could solve this problem for me with complete solutions. I have been at it for a couple of hours and I am running out of pencil. I would really appreciate your help!
Problem:
A helium balloon is used to lift a load of 110 N. The weight of the balloon's...