HELIUM


Helium is one of the so-called noble gases. Helium gas is unreactive, colourless, and odourless. Helium is available in pressurised tanks
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helium flag netherlands Helium
helium flag france hélium
helium flag germany  Helium
helium portugese flag elio
helium spanish flag helio
helium flag swedish Helium

Discovered : by Sir William Ramsay in London, and independently by P.T. Cleve and N.A. Langlet in Uppsala, Sweden in 1895

Helium Name Origin : The name is derived from the Greek ‘helios’, sun

Elemental helium is a colourless odourless monoatomic gas. Helium is the second most abundant element in the universe after hydrogen. a particles are doubly ionised helium atoms, He2+. Helium is used in lighter than air balloons and while heavier than hydrogen, is far safer since helium does not burn. Speaking after breathing an atmosphere rich in helium results in a squeaky voice (don't try it!).

Most of the helium existing in the universe today is thought to have been formed in the first few minutes of the big bang with a small amount later produced by stars. It is the second most abundant element in the universe, after hydrogen . .

There is very little helium on earth as nearly all present during and immediately after the earth's formation has long since been lost as it is so light. Just about all the helium remaining on the planet is the result of radioactive decay. While there is some helium in the atmosphere, currently its isolation from that source by liquefaction and separation of air is not normally economic. This is because it is easier, and cheaper, to isolate the gas from certain natural gases. Concentrations of helium in natural gas in the USA are as high as 7% and other good sources include natural gas from some sources in Poland. It is isolable from these gases by liquefaction and separation of from the natural gas. This would not normally be carried out in the laboratory and helium is available commercially in cylinders under pressure.

Most of us feel comfortable with the idea of something floating in water. We see that happen every day. In fact, people themselves float in water, so we have a way of directly experiencing water flotation. The reason why things float in water applies to air as well, so let's start by understanding water flotation.
Let's say that you take a plastic 1-liter soda bottle, empty out the soft drink it contains, put the cap back on it (so you have a sealed bottle full of air), tie a string around it like you would a balloon, and dive down to the bottom of the deep end of a swimming pool with it. Since the bottle is full of air, you can imagine it will have a strong desire to rise to the surface. You can sit on the bottom of the pool with it, holding the string, and it will act just like a helium balloon does in air. If you let go of the string the bottle will quickly rise to the surface of the water.

The reason that this soda bottle "balloon" wants to rise in the water is because water is a fluid and the 1-liter bottle is displacing one liter of that fluid. The bottle and the air in it weigh perhaps an ounce at most (1 litre of air weighs about a gram, and the bottle is very light as well). The litre of water it displaces, however, weights about 1,000 grams (2.2 pounds or so). Because the weight of the bottle and its air is less than the weight of the water it displaces, the bottle floats. This is the law of buoyancy.

Helium Flotation
Helium balloons work by the same law of buoyancy. In this case, the helium balloon that you hold by a string is floating in a "pool" of air (when you stand underwater at the bottom of a swimming pool, you are standing in a "pool of water" maybe 10 feet deep -- when you stand in an open field you are standing at the bottom of a "pool of air" that is many miles deep). The helium balloon displaces an amount of air (just like the empty bottle displaces an amount of water). As long as the helium plus the balloon is lighter than the air it displaces, the balloon will float in the air.
It turns out that helium is a lot lighter than air. The difference is not as great as it is between water and air (a litre of water weighs about 1,000 grams, while a litre of air weighs about 1 gram), but it is significant. Helium weighs 0.1785 grams per litre. Nitrogen weighs 1.2506 grams per litre, and since nitrogen makes up about 80 percent of the air we breathe, 1.25 grams is a good approximation for the weight of a litre of air.

Therefore, if you were to fill a 1-liter soda bottle full of helium, the bottle would weigh about 1 gram less than the same bottle filled with air. That doesn't sound like much -- the bottle itself weighs more than a gram, so it won't float. However, in large volumes, the 1-gram-per-liter difference between air and helium can really add up. This explains why blimps and balloons are generally quite large -- they have to displace a lot of air to float. The following diagram shows the different lifting capacities of different volumes of helium:

A 100-foot-diameter balloon can lift 33,000 pounds! Here is how you can figure out the lifting capacity of the helium in a spherical helium balloon:

Determine the volume of the balloon.
The volume of a sphere is 4/3 * pi * r3, where r is the radius of the balloon. So first determine the radius of the sphere (the radius is half the diameter). Cube the radius (multiply it by itself twice: r*r*r), multiply by 4/3 and then multiply by Pi. If you are measuring your balloon in feet, that gives you the volume of the balloon in cubic feet.
One cubic foot of helium will lift about 28.2 grams, so multiply the volume of the balloon by 28.2.
Divide by 448 -- the number of grams in a pound -- to determine the number of pounds it can lift.
So, for example, a 20-foot balloon has a radius of 10 feet. 10* 10 * 10 * 3.14 * 4/3 = 4,186 cubic feet of volume. 4,186 cubic feet * 28.2 grams/cubic feet = 118,064 grams. 118,064 grams / 448 grams per pound = 263 pounds of lifting force.

Although not used much anymore, hydrogen balloons were once quite popular. Hydrogen weighs just 0.08988 grams per litre. However, it is highly flammable, so the slightest spark can cause a huge explosion.

So why are helium and hydrogen so much lighter than air? It's because the hydrogen and helium atoms are lighter than a nitrogen atom. They have fewer electrons, protons and neutrons than nitrogen atoms do, and that makes them lighter (the approximate atomic weight of hydrogen is 1, helium is 4 and nitrogen is 14). Approximately the same number of atoms of each of these elements fills approximately the same amount of space. Therefore, the gases made of lighter atoms are lighter.

Hot Air
What about hot air balloons? They work by similar principles. If you heat up a gas it expands. In the case of a hot air balloon, when the gas inside the balloon expands the extra gas is pushed out the bottom of the balloon, meaning that there are fewer atoms inside the balloon, meaning that the air in the balloon is lighter than the air outside the balloon.
The amount of lifting power is controlled by how hot the air is. If you heat the air inside the balloon 100 degrees F hotter than the outside air temperature, then the air inside the balloon will be about 25 percent lighter than the air outside the balloon. So a cubic foot of air weighs about 35 grams at 32 degrees F. A cubic foot of hot air at 132 degrees F will weigh 25 percent less, or about 26.5 grams. The difference is 8.5 grams or so. So a hot air balloon has to be much bigger to support the same weight, but it will float because hotter air is lighter than cooler air.

You can get a sense for how much air contracts and expands as its temperature changes by performing the following experiment: Take two Ziplock bags (1-gallon size) and blow them up (you can do this by zipping the bag closed, then unzipping a small hole at one end of the zipper). Blow each bag up like a balloon and seal it while holding pressure on the last breath. You want these bags to be full -- you want the plastic on both inflated bags to be tense.

Now let the bags sit on the counter for a couple of minutes and cool off. You pumped 98.6 degree F air into them, and you want the temperature to drop to room temperature. The bags will probably become a little less tense in the process of cooling (makes sense...) so add one more puff of air to make them tense again.

Now stick one of the bags into your freezer for about three minutes, while leaving the other one on the counter. When you take the bag in the freezer out it will have deflated some. How much? By about 10 percent to 15 percent. It has deflated because cooler air is denser than warmer air. Compare the cold bag to the bag on the counter -- the cold bag will not be tense at all. Then a funny thing will happen as the cold bag warms up -- it will get tense again and return to its original size!

You can clearly see that warmer air takes up more space than cooler air. Therefore, warmer air is lighter than cooler air, and that is what makes a hot air balloon float!

Where Helium Comes From
If you put helium in a balloon and let go of the balloon, the balloon rises until it pops. When it pops, the helium that escapes has no reason to stop -- it just keeps going and leaks out into space.
Therefore, in the atmosphere there is very little helium at any given time. The helium that is there comes from alpha particles emitted by radioactive decay (see How Nuclear Radiation Works for details on alpha decay). In places that have a lot of uranium ore, natural gas tends to contain high concentrations of helium (up to 7 percent). This makes sense, since the decay of uranium emits lots of alpha particles and a natural gas pocket tends to be a sealed container underground. Helium is cryogenically distilled out of natural gas to produce the helium we put in balloons. A litre of air at sea level weighs about 1.25 grams. A litre is 1,000 cubic centimetres, or about 61 cubic inches -- the size of a 1-liter soda bottle. A litre of helium, on the other hand, weighs about 0.18 grams. If you weigh a 1-liter bottle filled with air and then weigh the same bottle filled with helium, it will weigh about 1.07 grams less. If the bottle itself weighed less than a gram, you couldn't weigh it at all -- it would float! You could turn the scale upside down and put it above the floating bottle to check its negative weight! Generally, a balloon has to be several litres in size before the 1-gram-per-litre weight difference of helium vs. air is enough to overcome the weight of the balloon itself and float.

If you could somehow fill a 1-litre bottle with a vacuum, it would float even better. A perfect vacuum weighs zero grams, so a litre of perfect vacuum weighs 0.18 grams less than a litre of helium. The problem, of course, is that building a lightweight container that can hold a vacuum is not nearly as easy as building a fabric envelope that can hold helium. The phrase Nature abhors a vacuum sums it up nicely. If you could figure out a way to do it, however, you would be set -- your vacuum balloon would float!

Note that you would not need to have a perfect vacuum. Any air that you take out of the envelope will lower the weight and cause lift.

Helium is a light inert gas and the second most abundant element in the universe. Helium was discovered in 1868 by J. Norman Lockyear in the spectrum of a solar eclipse. Our students encounter helium carrier gas with the chromatograph instruments and observe its discharge spectrum.

Atomic number - 2 Density g/mL 0 .0001787
Atomic weight u 4 .0026 Melting point K 0 .95
Bonding radius A 0 .93 Boiling point K 4 .215
Atomic radius A 0 .49 Heat of vaporization kJ/mol 0 .0845
Ionizations Potential V 24 .587 Heat of fusion kJ/mol -
Electronegativity - - Specific heat J/gK 5 .193
The oxide is unknown.
Crystal are hexagonal.

Electron config. : 1s2

Helium Isolation

There is very little helium on earth as nearly all present during and immediately after the earth's formation has long since been lost as it is so light. Just about all the helium remaining on the planet is the result of radioactive decay. While there is some helium in the atmosphere, currently its isolation from that source by liquefaction and separation of air is not normally economic. This is because it is easier, and cheaper, to isolate the gas from certain natural gases. Concentrations of helium in natural gas in the USA are as high as 7% and other good sources include natural gas from some sources in Poland. It is isolable from these gases by liquefaction and separation of from the natural gas. This would not normally be carried out in the laboratory and helium is available commercially in cylinders under pressure.

HELIUM
Discovered : by Sir William Ramsay in London, and independently by P.T. Cleve and N.A. Langlet in Uppsala, Sweden in 1895
 
Helium gas is a colourless, odourless, tasteless inert gas at room temperature and makes up about 0.0005% of the air we breathe.
 
During World War II, the army and navy funded experimental plants that produced non-explosive helium as a replacement for the explosive hydrogen gas used in observation balloons and airships. Once widely available, the element became crucial in ending the war.
 
Manhattan Project scientists used helium to make the atomic bomb. Helium was employed in military hospitals as a lifesaving anesthetic. Soldiers suffering with respiratory diseases were also administered helium.
 
Legendary British flying ace Douglas Bader, while recovering from serious wounds sustained during a dogfight over France, was treated with copious amounts of helium. Upon his triumphant return to the skies, Bader reputedly turned to his copilot and said, Hey Ben... Ben...Wanna see my Fokker?
 
In the liquid state, it is used to achieve extremely low temperatures in electronic devices or for studies in the region of 0-5 K. Helium is also the adequate gas for low temperature gas thermometers due to its low boiling point and almost ideal behaviour.
 
Helium is also used, mixed with oxygen, in asthma treatment because it diffuses very easily through the lungs. It can also be used in respiratory mixtures for high depth divers, because it is less soluble in blood than nitrogen.
 
Helium was also found very low quantities in rocks, natural and vulcan ic gases and radioactive minerals. Helium was initially used in dirigible-balloons. Nowadays, is used just like argon, in the production of an inert gaseous atmosphere during magnesium, aluminium and titanium welding; it can be used in the cooling of nuclear reactors as transfer media, since it is an inert gas.
 
The discovery of helium in radioactive materials was not totally understood until the discovery of radium in 1898. Then, it was verified that helium was a stable product of the radioactive elements disintegration.
 
Some scientists concluded that the helium gas present in Earth had that origin. Some others thought that the origin of helium on Earth was a survival of the "primordial helium".
 
Helium has a characteristic and bright spectrum that easily identifies the element. Its bright yellow spectrum stripe, responsible for the discovery of the element, is not hidden by any other element. Scientifically, helium is one of the most important elements.
 
A helium atom has two protons in its nucleus and two electrons around it. Helium nuclei were created during the big bang and so are some of the oldest and commonest objects in the Universe. About one quarter of the mass of the Universe is made up of helium atoms!
 
Helium has some very unusual properties when it is very cold. It can flow up the walls of containers and escape. It can conduct heat and electricity with almost no resistance, making it a superconductor.
 
It is a fact, because of their unreactivity, the noble gases were not discovered until the existence of helium
 
Because helium does not burn readily like hydrogen, it is a popular gas for lighter-than-air balloons. Interestingly, we can recognize the presence of helium due to its unusual effects on the vocal chords .  
In a helium-rich atmosphere, a person temporarily experiences a high-pitched, squeaky voice. Furthermore, this gas diffuses easily through the lungs, and therefore, it is commonly mixed with oxygen to create an artificial air supply for deep-sea divers.
 
Helium never crystallizes at the normal pressure. Quantum fluctuations are strong in Helium due to its low atomic weight. The interaction of Helium atoms is weak since it is a noble gas. As a result, Helium remains liquid even at absolute zero. When cooled to almost absolute zero, it becomes a super fluid. Super fluid Helium has zero viscosity.
 
Terrestrial Effects - Ice ages occur periodically on Earth and it has been suggested that reductions in the solar luminosity or some other solar variation may be partially responsible. If this is so, then a helium 3 instability which causes mixing in the solar core at discrete intervals could be the cause of periodic ice ages on Earth.
 
The time between theoretical core-mixing episodes in the Sun caused by the helium 3 instability and the intervals between major ice ages on the Earth are roughly similar
 
Energy Generation in the Sun - The Sun produces energy by fusing hydrogen to helium. This may be accomplished in a number of ways but in the Sun, a process known as the proton-proton chain is thought to be primarily responsible for energy generation
 
Helium in the rocks - Most helium on earth is produced by radioactive decay in rocks. The small atoms of helium gas have no trouble escaping from the rocks into the atmosphere.
 

Scientists can work out how fast helium is forming, how fast it escapes from rocks, how much enters the air, and how much can escape from the air into space. They can also measure the amount of helium in rocks and in the air. From this, they can calculate the maximum age of rocks and of the air. The results are puzzling to those who believe in billions of years. 
 

Of course, all such calculations depend on assumptions about the past, like the starting conditions and constant rates of processes. They can never prove the age of something. For that, we need an eye-witness
 
On earth, it is produced mainly by radioactive alpha (a)-decay. The great New Zealand physicist Ernest Rutherford (1871–1937) discovered that a-particles were really the nuclei of helium atoms. Radioactive elements in rocks—like uranium and thorium—produce helium this way, and it leaks out into the air
 
Helium in the sun is generally believed to be formed by nuclear fusion. This is where nuclei of hydrogen, the lightest element, combine to form helium with huge amounts of energy released.
 
Helium is the second lightest chemical element, with many unique properties. It is so named because it was first detected in light patterns in the sun (Greek helios) before it was detected on earth. All gases will condense into a liquid if cooled enough, but helium has the lowest condensation point of any substance (–269°C or –452°F).
 
Unlike other elements, it will never freeze, no matter how cold it is, except under high pressure.1 Also, liquid helium cooled below –271°C (–456°F) forms a unique phase called a super fluid, which flows perfectly, without any resistance (viscosity).2
 
We’re all familiar with helium, the very light gas that makes balloons and airships float in the air. Helium has an important safety advantage—it cannot burn or explode like hydrogen. It is also a vital part of air mixtures for breathing by deep-sea divers—unlike nitrogen, it hardly dissolves in blood or lipids (fatty compounds) even at high pressures
 
This avoids nitrogen narcosis, where the nervous system (60% lipid) becomes saturated with nitrogen, which can make divers feel as if they had consumed one martini per 100 ft of depth. It also avoid the bends or decompression sickness, a painful and dangerous condition caused by nitrogen bubbles forming in the diver’s blood, nervous system, joints, and under the skin, if the pressure drops too fast as the diver re-surfaces.
 
The helium/oxygen mixture (heliox) makes the voice very high-pitched, because sound travels much faster in helium than in air—a favourite party trick using helium-filled balloons.
 
So why are helium and hydrogen so much lighter than air? It's because the hydrogen and helium atoms are lighter than a nitrogen atom. They have fewer electrons, protons and neutrons than nitrogen atoms do, and that makes them lighter (the approximate atomic weight of hydrogen is 1, helium is 4 and nitrogen is 14).
 
Approximately the same number of atoms of each of these elements fills approximately the same amount of space. Therefore, the gases made of lighter atoms are lighter.


Helium - Here follows a list of interesting facts about helium

helium flag netherlands Helium
helium flag france hélium
helium flag germany Helium
helium portugese flag elio
helium spanish flag helio
helium flag swedish Helium

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