American astronomer Harold Shapley once marveled, “If God did create the world by a word, the word would have been hydrogen.” His reference underscores the fact that most things are made of hydrogen. As the first and the most basic element, hydrogen embodies many extraordinary physical properties that make it the ultimate energy source to power our society. Yet, this element remains an enigma—almost 500 years since its initial discovery. Its contradictory and often counterintuitive characteristics make “the mother of all atoms” among the most challenging element for scientists, inventors, and technologists to fully harness to benefit humanity.
Hydrogen has an atomic weight of 1.00794 (or 1.008 rounded up), a number that easily translates into a date of October 8 (10.08). As of last year, this date carries special significance; it is now known as National Hydrogen Day. The final digit of hydrogen’s atomic weight (8) also translates nicely into the eight most salient properties that make hydrogen so special for society.
In honor of National Hydrogen Day, we have created a new infographic to highlight hydrogen’s exceptional properties. The infographic classifies hydrogen’s properties into two sets that include “Hydrogen Highs” and “Hydrogen Lows.” We further contrast them in this article to illustrate why hydrogen is truly unique among all elements.
Hydrogen High #1: Life-giver vs. Hydrogen Low #1: Tiny Atom
All Life Depends on this tiny and “neutronless” atom.
As ancient as the universe itself, “elemental” is probably the most accurate way to describe hydrogen, as it is the foundation of all matter. Hydrogen is the source of all light we see, all energy we use, and all life around us. In the initial moments of the Big Bang, all of the hydrogen in the universe was created. From hydrogen, almost all other elements were formed. Over time, hydrogen coalesced into stars, nebulae, and entire planets—driven by its nuclear fusion process, which releases enormous amounts of energy. It is hydrogen’s fusion process that powers every star in the universe.
What makes hydrogen so basic and essential to the formation of matter and life—and sets it apart from all other elements in the universe—is its lack of a neutron. This makes hydrogen the simplest and smallest of all atoms, with only one proton at the center and one electron that orbits around it. It is so minuscule that a soccer ball measures 2.5 billion-times larger in size than a hydrogen atom. Its number one place in the Periodic Table makes it a contributor to molecule formation on Earth and across the universe.
Hydrogen High #2: Abundance vs. Hydrogen Low #2: Lighter than Air
A most abundant, yet elusive element.
Hydrogen is the most abundant element in the universe, comprising 75% of the universe by mass. It is found everywhere: from the water we drink to the stars in the sky. On Earth, hydrogen forms the most number of compounds. It is almost always found as part of larger molecules, most commonly water, because it bonds easily with other elements. Virtually all large, complex molecules contain hydrogen. Hydrogen is special among the elements for the reason it can easily form compounds in either the +1 or -1 oxidation states, where it can act essentially like a metal or a non-metal, depending on the circumstances. This fact is what allows hydrogen to be present in so many different compounds. It is also the reason why hydrogen resides on both sides of the Periodic Table. The elements on the left of the Periodic Table form compounds by giving up electrons, while those on the right accept electrons in forming compounds.
Holding the lowest atomic weight of any element in the universe, hydrogen is the lightest of all gases and is 14.4-times lighter than air. Hydrogen gas, which consists of two hydrogen atoms bonded to one another (called diatomic molecules or H2), is quite rare on Earth. Because it is lighter than the atmosphere, hydrogen easily escapes into space. This was a key factor behind why many other elements were discovered before the most abundant element of them all.
Hydrogen High #3: Highest Energy by Weight vs. Hydrogen Low #3: Lowest Energy by Volume
A contradictory element.
Pound-for-pound, hydrogen remains unrivaled for its ability to release more energy than other alternatives. The reason for this is because it provides a very high specific impulse, meaning that it can deliver a large amount of energy per-gram of fuel. Hydrogen is, by far, the most energy-dense fuel by mass, so it reacts exothermically with oxygen quite well over a wide range of conditions. To put this “hydrogen high” in perspective, the combustion of hydrogen releases three-times more energy than that of gasoline and almost seven-times that of coal, on an equivalent weight basis. That is why NASA uses it as a rocket fuel.
The problem encountered is the fact that hydrogen is an incredibly light gas. Although hydrogen delivers the highest energy density by weight, it has the lowest energy density per unit volume of all elements, both as a gas and as a liquid. This energy density, which measures the compactness (or mass) of hydrogen atoms is so small that a roomful of pure hydrogen gas (or an equivalent of 1,333 gallons) would weigh only 1 pound. So the proverbial challenge is how to get enough hydrogen mass in one place to be of practical use. Traditionally, the answer has been to either compress or liquefy hydrogen by lowering its temperature to just above absolute zero, making it more expensive to handle than other fuels.
Hydrogen High #4: A ‘Perfect’ Gas vs. Hydrogen Low #4: Lowest Boiling Point
A perfect gas that generates water when burned.
In its gaseous state, hydrogen behaves a lot like a ‘perfect gas.’ This is because the H2 molecule is very small, has no net charge, and is non-polar. As a result, there is very little interaction between the hydrogen atoms in the gas state. This gives hydrogen a unique ability to transfer heat with a very high heat conductivity (20-times higher) and specific heat capacity (9-times higher) compared to other gases. When used as a fuel, the “exhaust” immediately bonds with the surrounding oxygen in air, producing only water—which reinforces why hydrogen is, indeed, the perfect gas to help combat climate change.
However, for hydrogen to be stored and used effectively as a fuel, it is often kept as a liquid. This proves challenging because hydrogen has the lowest boiling point (the transition from liquid to gas) and the lowest melting point (the transition from liquid to solid) of all substances apart from helium. To store hydrogen as a liquid, it must be kept at an extremely low temperature of -253° C to prevent it from boiling, which makes it hard to deal with for practical uses.
Eight Essential Properties Create Life-Sustaining Magic
Hydrogen is the basis for all life and the foundation of most matter in the universe; it holds the key to a more sustainable future. Hydrogen is so elemental that if there were, in fact, a special language of the universe, it would definitely be hydrogen. The eight essential properties we covered make hydrogen not only a keystone for understanding our natural world but also extremely useful in solving many of the energy problems we face today. Its potential as a clean energy source is limitless due to its abundance and its energetic properties. However, for all of its simplicity, the full energy potential of the most basic of all elements has yet to be realized. Joi Scientific’s mission is to expedite the world’s transition to clean and affordable hydrogen so everyone, everywhere can finally realize the wonders of the incredible number-one element.
The Ultimate Hydrogen Cheat Sheet
Click here to download our new infographic, “Hydrogen: 8 Highs and Lows that Make It Exceptional.”
As the Hydrogen 2.0 ecosystem gains momentum, we’ll be sharing our views and insights on the new Hydrogen 2.0 Economy. We also update our blog every week with insightful and current knowledge in this growing energy field.