Hydrogen1 is the most abundant element2 in the universe3 – all of the hydrogen in the universe has its origin in the first few moments after the Big Bang. It is the third most abundant element on the Earth’s surface after oxygen and silicon4.
The Earth’s atmosphere5 contains very little hydrogen gas – its very low density6 enables it to escape the Earth’s gravity7 more easily than denser gases8 like oxygen9.
Most of the Earth’s hydrogen is in the form of chemical compounds such as water and hydrocarbons.
How we use hydrogen
At high temperatures and pressures, hydrogen can combine with nitrogen10 to form ammonia11. This colourless gas with a fishy odour is used extensively in the production of fertilisers and nitric acid12.
ammonia: N2(g) + 3H2(g) → 2NH3(g)
ammonium13 nitrate14: NH3(g) + HNO3(l) → NH4NO3(s)
Hydrogen, obtained from methane15 gas (natural gas) is used in the manufacture of methanol16.
CH4(g) + H2O(g) → CO(g) + 3H2(g)
CO(g) + 2H2(g) → CH3OH(l)
Methanol is an important industrial chemical used as a solvent17, a fuel18 and in making other chemicals19 such as formaldehyde for use in the plastics industry. Methanol can be readily converted into synthetic20 petrol.
Oil refineries use large amounts of hydrogen in processes such as hydro cracking, where large hydrocarbon21 molecules22 are split into smaller, more useful molecules like octane.
In the food industry, hydrogen gas is used to convert oils such as sunflower seed oil into semi-solids for use in spreads like margarine.
Other uses include rocket fuel (Space Shuttle23 main engine), welding, hydrochloric acid production and reducing metallic ores24 like tungsten oxide25 into the pure metal26.
Fuel cells
Rechargeable batteries are used in a variety of modern day appliances such as cell phones, iPods, cordless power tools and video camcorders.
One of their drawbacks is that, when the chemicals within the battery27 have been used up, no current28 can be drawn. Recharging replenishes the chemicals and the battery can be used again, but this is time-consuming and inconvenient.
A fuel cell29 is designed such that a continuous supply of chemical reactants is available. No recharging is needed, and the cell30 can run continuously provided there is a constant supply of reactants.
Hydrogen-oxygen fuel cells are lightweight and efficient and produce water as the only waste product. As the cell operates, heat31 is also produced. This can be captured and put to good use. Fuel cells on board the Space Shuttle deliver the same power32 as batteries weighing 10 times as much and produce water and heat for the crew to use.
Hydrogen-powered cars using fuel cell technologies are becoming increasingly popular.
Hydrogen in history
Hydrogen gas was first recognised as a substance in its own right by Henry Cavendish in 1766. He referred to it as ‘inflammable air’. In 1783, Antoine Lavoisier gave it the name ‘hydrogen’ from the Greek ‘hydro’, meaning water, and ‘genes’ meaning creator.
Hydrogen-filled balloons and airships provided the first reliable form of air travel. Rigid airships called Zeppelins, filled with hydrogen to provide lift33, started commercial flights in 1910. The first non-stop trans-Atlantic flight was made by the British airship R34 in 1919. The best known airship was the Hindenburg, which was destroyed in a mid-air fire over New Jersey, USA, on 6 May 1937. This event signalled the end of commercial travel using hydrogen-filled airships.
Fusion reactions
Hydrogen plays a vital role in fusion reactions that power stars like our sun. These reactions not only produce heavier elements34 but also release very large amounts of energy.
The vast amounts of energy emitted by the sun come from nuclear reactions that fuse35 hydrogen atoms into helium36 atoms. During this process, scientists have discovered that there is a slight loss of mass37 during the fusion process.
Using Einstein’s famous equation E=mc2, it is possible to calculate the energy released in this process.
For example if one kilogram38 of matter39 is transformed then the energy released is:
E = mc2
= 9 x 1016 joules
= 1 x (3 x 108) x (3 x 108)
This amount of energy is sufficient to supply over 2.5 million New Zealand homes with all of their annual energy needs.
It is estimated that the mass of the sun is decreasing at the rate of 4.3 x 109 kg per second. This equates to 3.87 x 1026 joules of energy being radiated each second.
Nature of science
Science is a blend of logic and imagination. In the development of fuel cell technologies, these two features of the human mind play a very prominent role.
Related content
Learn more about how elements are formed.
- hydrogen: First element on the periodic table – symbol H, with the atomic number of 1, meaning that it has a single proton in its nucleus.
- element: A substance made of atoms that all have the same atomic number. Elements cannot be split into simpler substances using normal chemical methods.
- universe: All matter and energy, including the Earth, the galaxies and the contents of intergalactic space, regarded as a whole.
- silicon: A semimetal – symbol Si, atomic number 14.
- atmosphere: 1. The layer of gas around the Earth. 2. (atm) A non-SI unit of pressure equivalent to 101.325 kPa.
- density: How tightly a certain amount of matter (atoms or molecules) of a substance is compacted in a given volume. Density is commonly measured in grams per millilitre (g/ml) or cubic centimetre (g/cm3).
- gravity: The force attracting something towards the centre of Earth (or other large mass, like a moon or planet) – the reason that things fall to Earth.
- gases: The state of matter distinguished from the solid and liquid states. Gases have the ability to diffuse readily and to become distributed uniformly throughout any container.
- oxygen: A non-metal – symbol O, atomic number 8. Oxygen is a gas found in the air. It is needed for aerobic cellular respiration in cells.
- nitrogen: A non-metal – symbol N, atomic number 7. Nitrogen is essential for life. It is a component of many molecules that make up cells, including DNA and proteins.
- ammonia: A compound of nitrogen and hydrogen with the formula NH3. It is a colourless gas with a characteristic pungent smell.
- acid: A hydrogen-containing substance that is capable of donating a hydrogen ion to another substance.
- ammonium: NH4+. Derived from ammonia by combination with a hydrogen ion. A nitrogen compound taken up by plants from soils.
- nitrate: A chemical composed of three oxygen atoms for every nitrogen atom.
- methane: CH4, a gas that contributes to the greenhouse effect.
- methanol: A liquid alcohol – chemical formula CH3OH.
- solvent: A liquid that dissolves another substance to form a solution. For example, water is a solvent for sugar – when sugar is dissolved in water, it becomes a sugar solution.
- fuel: 1. A combustible substance that provides energy. 2. A body fuel such as fat, carbohydrates and protein that supplies energy for animals’ activities.
- chemicals: Everything is made up of chemicals. All matter (anything made of atoms) can be called chemicals. They can be in any form – liquid, solid or gas. Chemicals can be a pure substance or a mixture.
- synthetic: Made in a laboratory or factory by a chemical process, usually to imitate a natural process.
- hydrocarbon: A chemical compound made up of hydrogen and carbon only. Mainly obtained from petroleum.
- molecule: Two or more atoms bonded together. The molecule of an element has all its atoms the same. The molecule of a compound has two or more different atoms.
- space shuttle: A reusable NASA spacecraft that carries astronauts, space station material and satellites into a low orbit around Earth.
- ore: Rock or sediment from which we can extract elements and minerals.
- oxide: A chemical compound made up of oxygen combined with at least one other element. Most of the Earth’s crust consists of oxides.
- metal: Any of a category of elements that usually have a shiny surface, are generally good conductors of heat and electricity and can be melted or fused, hammered into thin sheets or drawn into wires (for example, copper).
- battery: A combination of electrolytic cells that enables chemical energy to be transformed into electrical energy.
- current: The flow of electric charge through a conductor.
- fuel cell: Uses a continuous supply of fuel to convert chemical energy into electrical energy.
- cell: 1. Building block of the body. A human is made of millions of cells, which are adapted for different functions and can reproduce themselves exactly. 2. A simple electrolytic device that enables chemical energy to be transformed into electrical energy.
- heat energy (heat): Heat energy: the transfer of energy in materials from the random movement of the particles in that material. The greater the random movement of particles the more heat energy the material has. Temperature is a measure of the heat energy of a material.
Heat: the flow of energy from a warm object to a cooler object. - power: 1. The rate at which work is done (defined as work divided by time taken). 2. Mechanical or physical energy, force or momentum.
- lift: In aerodynamics, upward force produced by a difference in pressure due to airflow.
- element: A substance made of atoms that all have the same atomic number. Elements cannot be split into simpler substances using normal chemical methods.
- fuse: 1. A safety device made of a short length of resistance wire that will melt if more than the allowed current is present in the circuit. 2. To join together.
- helium: (He) A colourless, odourless inert gaseous element occurring in natural gas and with radioactive ores.
- mass: The amount of matter an object has, measured in kilograms.
- kilogram: The base unit of mass in the International System of Units (SI).
- matter: The basic structural component of all things that have mass and volume.