Hydrogen Gas: 5 Hidden Properties You Need to Know!

Hydrogen, symbolized as H2, reigns supreme as the most abundant element in the cosmos. From the fiery hearts of stars to the vast interstellar medium, hydrogen constitutes the very fabric of the universe.

The Promise of a Clean Energy Future

Beyond its cosmic prevalence, hydrogen holds immense promise here on Earth, particularly as a clean energy carrier. In a world grappling with the urgent need to decarbonize, hydrogen emerges as a versatile and potentially game-changing solution.

It can be produced from diverse sources, including renewable energy and nuclear power, and its combustion produces only water vapor, making it a truly clean fuel.

Beyond the Basics: Exploring Hydrogen’s Uncommon Traits

While the potential of hydrogen in clean energy is increasingly recognized, many of its fundamental properties remain less widely known. This article aims to delve deeper, to explore the lesser-known facets of hydrogen gas that often go unmentioned.

We will journey beyond the familiar territory of its role in fuel cells and combustion engines to uncover the unique and sometimes surprising characteristics that govern its behavior. These hidden properties play a crucial role in how we produce, store, and utilize this remarkable element.

Hydrogen’s potential as a future fuel source is undeniable, yet its true versatility extends far beyond simple combustion. Understanding its behavior requires us to first appreciate the nuances within its own "family" – its isotopes.

Hydrogen’s Family: The Unique Behavior of Isotopes

Isotopes, in essence, are variations of a chemical element which share the same number of protons and electrons, but differ in the number of neutrons. This difference in neutron count results in a variation in atomic mass.

Hydrogen, uniquely, has three naturally occurring isotopes, each with its own distinct name and properties: Protium, Deuterium, and Tritium.

Protium: The Common Form

Protium, often simply referred to as hydrogen, is the most abundant isotope, making up over 99.98% of naturally occurring hydrogen. Its nucleus consists of a single proton and no neutrons. This makes it the simplest and lightest of all atomic nuclei.

Deuterium: The Heavy Hydrogen

Deuterium, sometimes represented as "D" or ²H, contains one proton and one neutron in its nucleus. This extra neutron doubles its mass compared to protium, leading to notable differences in its physical and chemical properties. It’s found naturally but is far less abundant than protium.

Tritium: The Radioactive Variant

Tritium, symbolized as "T" or ³H, is the rarest and heaviest of the hydrogen isotopes. Its nucleus comprises one proton and two neutrons. Tritium is also radioactive, undergoing beta decay. This means it spontaneously transforms, emitting an electron and an antineutrino, eventually becoming helium-3. Due to its radioactivity, tritium has a limited lifespan.

Mass Matters: Impact on Properties

The varying masses of hydrogen isotopes significantly impact their properties. These differences are most noticeable when comparing protium and deuterium due to the substantial relative mass increase.

Reaction Rates

Isotopes exhibit slightly different reaction rates. Deuterium-containing compounds, for example, often react slower than their protium counterparts. This is known as the kinetic isotope effect, and it arises from the greater energy required to break bonds involving heavier isotopes.

Boiling Points

Boiling points are also affected. Deuterium oxide (D₂O), also known as heavy water, has a slightly higher boiling point (101.42 °C) compared to ordinary water (H₂O, 100 °C). This difference, while small, is significant in certain applications.

Zero-Point Energy

Zero-point energy, the lowest possible energy that a quantum mechanical system may have, is influenced by an atom’s mass. Heavy atoms such as deuterium tend to have a lower zero-point energy than protium, which affects the stability of chemical bonds.

Isotopic Applications: Nuclear Reactors and Fusion Research

The unique properties of hydrogen isotopes make them valuable in various scientific and technological applications.

Deuterium in Nuclear Reactors

Deuterium, in the form of heavy water (D₂O), is used as a moderator in certain nuclear reactors. It slows down neutrons effectively, increasing the probability of nuclear fission and sustaining the chain reaction.

Tritium in Fusion Research

Tritium is a crucial fuel component in many experimental fusion reactors. The deuterium-tritium (D-T) fusion reaction is considered the most promising path toward achieving sustained nuclear fusion, as it requires lower temperatures compared to other fusion reactions.

Tracers in Chemical Reactions

Both deuterium and tritium can be used as tracers in chemical and biological research. By incorporating these isotopes into molecules, scientists can track their pathways and transformations within complex systems. This is because their slightly different masses allow for easy detection using techniques like mass spectrometry.

The "family" of hydrogen isotopes, though seemingly simple, exhibits a range of behaviors with far-reaching implications. Understanding these subtle yet significant differences is crucial for harnessing the full potential of hydrogen in both current and future technologies.

Hydrogen’s potential as a future fuel source is undeniable, yet its true versatility extends far beyond simple combustion. Understanding its behavior requires us to first appreciate the nuances within its own "family" – its isotopes. With a grasp on these fundamental building blocks, we can now turn our attention to how hydrogen is actually produced, and how these methods impact its suitability for different applications.

From Production to Purity: How Methods Shape Hydrogen’s Quality and Cost

The journey of hydrogen from a raw material to a usable fuel is a complex one, heavily influenced by the production method employed. The two most prevalent methods, Steam Methane Reforming (SMR) and Electrolysis, offer distinct pathways to hydrogen production, each with its own set of advantages and drawbacks concerning gas purity and overall cost. Understanding these differences is crucial for assessing the viability of a hydrogen economy.

Steam Methane Reforming (SMR): An Established Workhorse

SMR is currently the most common and cost-effective method for producing hydrogen on a large scale.

It involves reacting methane (typically from natural gas) with steam at high temperatures and pressures in the presence of a catalyst.

The resulting "syngas" (a mixture of hydrogen and carbon monoxide) is then further processed in a water-gas shift reaction to produce more hydrogen and carbon dioxide.

Finally, carbon dioxide is removed, and the remaining gas is purified to yield hydrogen.

Purity Considerations in SMR

While SMR is efficient and economical, it often results in hydrogen that isn’t as pure as hydrogen produced using other methods.

Trace amounts of carbon monoxide (CO), carbon dioxide (CO2), and other impurities may remain even after purification.

The presence of these impurities can be detrimental to certain applications, particularly fuel cells, where they can poison the catalyst and reduce performance.

Advanced purification techniques, such as pressure swing adsorption (PSA), can be employed to achieve higher purity levels, but they add to the overall cost of production.

Electrolysis: A Clean but Costly Alternative

Electrolysis offers a cleaner route to hydrogen production.

It involves using electricity to split water (H2O) into its constituent elements: hydrogen and oxygen.

If the electricity used in the process comes from renewable sources like solar or wind power, the resulting hydrogen is considered "green hydrogen," offering a truly carbon-neutral fuel option.

Purity Advantages of Electrolysis

Electrolysis generally produces very high-purity hydrogen, often exceeding 99.99%.

Since the only feedstock is water, there are virtually no carbon-based contaminants.

This high purity makes electrolytically produced hydrogen ideal for applications that demand stringent purity requirements, such as fuel cells used in vehicles or sensitive industrial processes.

Cost Barriers to Widespread Adoption

Despite its advantages, electrolysis currently faces significant cost barriers.

The electricity required to split water is a major expense, and the capital costs associated with electrolyzer equipment can also be substantial.

As renewable energy costs continue to decline and electrolyzer technology improves, the economic competitiveness of electrolysis is expected to increase.

Cost Implications and the Hydrogen Economy

The cost of hydrogen production is a critical factor determining the feasibility of a hydrogen economy.

SMR, with its lower production costs, currently provides the most economically viable option for large-scale hydrogen production.

However, the associated carbon emissions raise concerns about its long-term sustainability.

Electrolysis, particularly when powered by renewable energy, offers a more environmentally friendly alternative.

However, until costs can be significantly reduced, its widespread adoption may be limited to niche applications where high purity and environmental benefits outweigh the higher price.

Government policies, technological advancements, and increasing demand will ultimately shape the future of hydrogen production and its role in a sustainable energy future. The choice between SMR, electrolysis, and other emerging production methods will depend on a complex interplay of economic, environmental, and technological considerations.

Hydrogen’s potential as a future fuel source is undeniable, yet its true versatility extends far beyond simple combustion. Understanding its behavior requires us to first appreciate the nuances within its own "family" – its isotopes. With a grasp on these fundamental building blocks, we can now turn our attention to how hydrogen is actually produced, and how these methods impact its suitability for different applications.

The Storage Challenge: Containing and Transporting Hydrogen Safely

The promise of a hydrogen-powered future hinges not just on efficient production, but also on effective storage and transportation.

Hydrogen presents unique challenges due to its physical properties, demanding innovative solutions to ensure its safe and economical deployment.

One of the most significant hurdles is its low volumetric energy density.

This means that hydrogen occupies a large volume for a given amount of energy compared to traditional fuels like gasoline.

Effectively, storing enough hydrogen to power a vehicle or a power plant requires either compressing it to extremely high pressures, liquefying it at cryogenic temperatures, or binding it to a storage material.

Overcoming Low Volumetric Energy Density

The central challenge in hydrogen storage stems from its inherent nature.

To put it plainly, hydrogen is incredibly light and diffuse, making it difficult to pack a significant amount of energy into a small space.

This necessitates advanced and often complex storage solutions.

The industry is actively researching and developing various methods.

Each method strives to maximize the amount of hydrogen that can be stored per unit volume while maintaining safety and cost-effectiveness.

Compressed Gas Storage

One of the most straightforward approaches involves compressing hydrogen gas to high pressures, typically 350 to 700 bar (5,000 to 10,000 psi).

This method is relatively mature and used in some hydrogen-powered vehicles.

However, it requires robust and heavy storage tanks to withstand the immense pressure.

Advantages of Compressed Gas

Compressed gas storage benefits from a relatively simple technology and established infrastructure for gas compression.

It’s also comparatively energy-efficient compared to liquefaction.

Disadvantages of Compressed Gas

The major disadvantage is the bulk and weight of the high-pressure tanks.

This significantly impacts vehicle efficiency and overall storage capacity.

Liquid Hydrogen Storage

Another approach involves cooling hydrogen to extremely low temperatures (-253°C or -423°F) to liquefy it.

Liquefaction dramatically increases the volumetric energy density.

This means more hydrogen can be stored in a smaller volume compared to compressed gas.

Advantages of Liquid Hydrogen

Liquid hydrogen offers a higher energy density than compressed gas, which allows for longer driving ranges in vehicles.

Disadvantages of Liquid Hydrogen

The liquefaction process is energy-intensive.

It consumes a significant portion of the energy stored in the hydrogen itself.

Furthermore, liquid hydrogen is susceptible to boil-off, the gradual evaporation of the liquid due to heat leak into the storage tank, leading to losses over time.

Special insulated cryogenic tanks are required to minimize boil-off.

Materials-Based Storage

Materials-based storage methods aim to bind hydrogen to a solid material through either adsorption or absorption.

Adsorption involves hydrogen adhering to the surface of a material.

Absorption involves hydrogen reacting with the material to form a chemical compound called a hydride.

Metal Hydrides

Metal hydrides offer the potential for high volumetric energy density and safer storage compared to compressed gas or liquid hydrogen.

However, many metal hydrides are heavy, which reduces the gravimetric energy density (the amount of hydrogen stored per unit mass).

Also, the kinetics of hydrogen absorption and desorption can be slow, and some hydrides require high temperatures to release the hydrogen.

Adsorbents

Adsorbents like activated carbon, metal-organic frameworks (MOFs), and other porous materials offer high surface areas for hydrogen to adhere to.

They can operate at lower pressures and temperatures than metal hydrides.

However, their hydrogen storage capacity is often lower, and the interaction between hydrogen and the material can be weak.

Technological Advancements in Storage

Significant research and development efforts are focused on improving hydrogen storage technologies.

These efforts span a wide range of areas, including:

• Developing lighter and stronger materials for compressed gas tanks.
• Improving the efficiency of hydrogen liquefaction processes.
• Synthesizing novel materials with enhanced hydrogen storage capacity and kinetics.
• Developing advanced insulation techniques to minimize boil-off in liquid hydrogen tanks.
• Creating more efficient and compact hydrogen compressors and pumps.

Advancements in materials science, nanotechnology, and chemical engineering are driving progress in this critical area.

The development of safe, efficient, and cost-effective hydrogen storage solutions is essential for unlocking the full potential of hydrogen as a clean energy carrier.

The industry is actively researching and developing various methods to improve upon the storage challenges, but to truly utilize hydrogen’s power we must address its handling.

Taming the Flame: Understanding Combustion and Ensuring Hydrogen Safety

Hydrogen’s appeal as a clean energy source is significantly boosted by its clean combustion byproducts. When hydrogen burns, it primarily produces water vapor, making it a potentially emissions-free alternative to fossil fuels.

However, this seemingly benign characteristic masks some unique safety challenges that need careful consideration.

The Science of Hydrogen Combustion

The combustion of hydrogen is a relatively simple chemical reaction: 2H₂ + O₂ → 2H₂O.

This reaction releases a substantial amount of energy in the form of heat, which can be harnessed for various applications.

Unlike the combustion of hydrocarbons, which release carbon dioxide and other pollutants, the primary product of hydrogen combustion is water.

This makes it attractive as a clean-burning fuel.

However, achieving complete and efficient combustion requires careful control of factors like temperature, pressure, and the air-to-fuel ratio.

Hydrogen: The Clean-Burning Fuel

The absence of carbon emissions is arguably hydrogen’s greatest advantage. Its combustion produces primarily water vapor, contributing to cleaner air and reduced greenhouse gas emissions.

This is particularly important in sectors like transportation and power generation, where the burning of fossil fuels is a major source of pollution.

However, "clean-burning" doesn’t mean "risk-free." The properties of hydrogen itself demand careful handling and safety protocols.

The Double-Edged Sword: Hydrogen Safety Concerns

Despite its clean combustion, hydrogen presents unique safety concerns. Its most notable characteristic is its exceptionally wide flammability range, from 4% to 75% in air.

This means that hydrogen can ignite at very low concentrations, making it easier to form a flammable mixture compared to other fuels like gasoline or natural gas.

Understanding the Flammability Range

The wide flammability range of hydrogen is due to its high diffusion coefficient and low ignition energy.

Hydrogen disperses quickly in air.

Its low ignition energy means only a small amount of energy is needed to initiate combustion.

This combination makes it critical to prevent leaks and ensure proper ventilation in areas where hydrogen is stored or used.

The Risk of Explosions

Hydrogen explosions can occur if a flammable mixture is ignited in a confined space.

The rapid expansion of gases during combustion can generate significant pressure, leading to structural damage and potential injury.

While hydrogen explosions are not inherently more powerful than those of other fuels, their rapid flame propagation speed can make them particularly dangerous.

Mitigation strategies include proper ventilation, leak detection systems, and explosion-resistant construction materials.

Mitigating Risks: Safety Measures and Detection Technologies

To safely harness the benefits of hydrogen, robust safety measures and advanced detection technologies are essential.

These measures aim to prevent leaks, detect flammable mixtures, and mitigate the consequences of an accidental ignition.

Leak Detection Systems

Early detection of hydrogen leaks is crucial to prevent the formation of flammable mixtures.

Various types of sensors are available, including electrochemical, thermal conductivity, and catalytic sensors.

These sensors can detect even small concentrations of hydrogen in air, providing an early warning of a potential hazard.

Real-time monitoring systems can track sensor readings and alert personnel in case of a leak, enabling prompt intervention.

Ventilation and Inerting

Proper ventilation is essential to prevent the accumulation of hydrogen in enclosed spaces.

Ventilation systems should be designed to ensure adequate air exchange, diluting any leaked hydrogen below its flammability limit.

Inerting involves displacing air with an inert gas like nitrogen or argon, preventing the formation of a flammable mixture altogether.

Material Selection and Design

The choice of materials used in hydrogen storage and handling systems is critical.

Materials must be compatible with hydrogen to prevent embrittlement, which can weaken the material and lead to leaks or failures.

Design considerations include minimizing the number of potential leak points, using robust seals and gaskets, and providing adequate structural support.

Training and Procedures

Comprehensive training for personnel involved in hydrogen handling and use is essential.

Training programs should cover the properties of hydrogen, potential hazards, safety procedures, and emergency response protocols.

Regular drills and simulations can help ensure that personnel are prepared to respond effectively in the event of an incident.

Flame Arrestors and Relief Valves

Flame arrestors are devices that prevent the propagation of a flame through a flammable gas mixture.

They work by cooling the flame below its ignition temperature, effectively stopping it from spreading.

Relief valves are designed to vent excess pressure in a system, preventing overpressure and potential explosions.

These safety devices are crucial components of hydrogen systems, providing an additional layer of protection against accidents.

By understanding the unique properties of hydrogen and implementing appropriate safety measures, we can harness its potential as a clean energy source while minimizing the risks.

Fuel Cells: Powering the Future with Hydrogen Energy

Hydrogen, having navigated the challenges of production, storage, and safety, truly shines in its application within fuel cells.

These ingenious devices offer a pathway to harnessing hydrogen’s energy in a clean and efficient manner.

They directly convert the chemical energy of hydrogen into electricity, unlocking its potential as a powerful and versatile energy carrier.

The Science Behind Hydrogen Fuel Cells

At its core, a hydrogen fuel cell operates on a deceptively simple principle: the reverse electrolysis of water.

Unlike combustion, which involves burning fuel, fuel cells generate electricity through an electrochemical reaction.

A typical fuel cell consists of an anode, a cathode, and an electrolyte membrane.

Hydrogen gas is fed to the anode, where a catalyst facilitates its separation into protons and electrons.

The protons pass through the electrolyte membrane to the cathode, while the electrons are forced to travel through an external circuit, generating electricity.

At the cathode, the protons, electrons, and oxygen from the air combine to form water, the only byproduct of the process.

Fuel Cell Applications: A Diverse Landscape

The versatility of hydrogen fuel cells makes them suitable for a wide range of applications, from transportation to power generation and even portable electronics.

Transportation: The Zero-Emission Vehicle

In the transportation sector, hydrogen fuel cells are emerging as a promising alternative to internal combustion engines and battery-electric vehicles.

Fuel cell vehicles (FCVs) offer several advantages, including longer driving ranges, faster refueling times, and zero tailpipe emissions.

Companies like Toyota, Hyundai, and Honda have already released FCV models, and the technology is rapidly maturing.

Stationary Power Generation: Reliable and Clean

Fuel cells can also be used for stationary power generation, providing a reliable and clean source of electricity for homes, businesses, and even entire communities.

These systems can operate on natural gas, biogas, or even hydrogen, making them adaptable to various fuel sources.

Fuel cell power plants offer high efficiency, low emissions, and the potential for combined heat and power (CHP) applications, where waste heat is recovered and used for heating or cooling.

Portable Electronics: Power on the Go

The compact size and high energy density of fuel cells make them ideal for portable electronics, such as laptops, smartphones, and drones.

Micro-fuel cells can provide longer runtimes compared to traditional batteries, and they can be quickly refueled with hydrogen.

Fuel Cells as a Clean Energy Alternative

The potential of hydrogen fuel cells as a clean energy alternative to fossil fuels is immense.

By replacing combustion-based technologies with fuel cells, we can significantly reduce greenhouse gas emissions, improve air quality, and enhance energy security.

However, the widespread adoption of fuel cells faces several challenges, including the high cost of fuel cell technology and the lack of a robust hydrogen infrastructure.

Continued research and development, coupled with supportive government policies, are crucial for unlocking the full potential of hydrogen fuel cells and ushering in a cleaner, more sustainable energy future.

Hydrogen’s Cosmic Role: NASA’s Use in Space Exploration

The story of hydrogen is interwoven with the narrative of space exploration. NASA’s reliance on this lightweight yet powerful element stretches back to the dawn of the space age. Hydrogen is not merely a component, but a cornerstone of humanity’s ventures beyond Earth’s atmosphere.

A History Forged in Fire: Hydrogen as Rocket Fuel

From the thunderous launches of the Saturn V rockets during the Apollo missions, to the Space Shuttle’s main engines, liquid hydrogen has been the fuel of choice for propelling massive payloads into orbit and beyond.

Its exceptional energy-to-weight ratio makes it an unparalleled propellant.

The combination of liquid hydrogen and liquid oxygen creates a potent mixture. This delivers the immense thrust required to overcome Earth’s gravity.

This efficiency is crucial when every kilogram counts in the unforgiving environment of space.

Powering Exploration: Beyond Propulsion

Beyond its role as rocket fuel, hydrogen has also played a vital, if less publicized, role in power generation within space missions.

Fuel cells, utilizing hydrogen as their primary fuel source, have provided electricity for spacecraft systems, life support, and scientific experiments.

These fuel cells offer a clean and reliable alternative to solar panels in situations where sunlight is limited. An example is during long-duration missions or when operating on the shadowed side of a planet.

The Space Shuttle, for example, relied on hydrogen fuel cells to generate electricity and potable water for the crew.

The Future is Hydrogen: Ongoing Research and Development

NASA’s commitment to hydrogen extends far beyond its historical applications. Ongoing research focuses on developing advanced hydrogen technologies for future space missions.

These missions could greatly benefit from the energy that hydrogen provides.

In-Situ Resource Utilization (ISRU)

One promising area of research is In-Situ Resource Utilization (ISRU), which involves extracting resources from extraterrestrial environments.

Hydrogen, potentially sourced from water ice on the Moon or Mars, could be used to create propellant, fuel cells, or other consumables, reducing the need to transport vast quantities of supplies from Earth.

This would significantly lower the cost and complexity of long-duration missions.

Advanced Propulsion Systems

NASA is also exploring advanced propulsion systems that utilize hydrogen, such as nuclear thermal propulsion (NTP).

NTP systems use a nuclear reactor to heat hydrogen to extremely high temperatures, creating significantly higher thrust and efficiency compared to traditional chemical rockets.

This technology could drastically reduce travel times to distant destinations like Mars, opening up new possibilities for deep-space exploration.

Cryogenic Fluid Management

The challenges of storing and handling cryogenic propellants like liquid hydrogen in the harsh environment of space are also being addressed.

Research focuses on developing advanced insulation materials, zero-boil-off storage systems, and efficient transfer technologies to minimize propellant losses during long-duration missions.

These advancements are essential for enabling future missions that require large quantities of hydrogen.

Hydrogen’s role in space exploration is not just a thing of the past, it’s the key to unlocking humanity’s future among the stars. NASA’s continued investment in hydrogen technologies signals a clear vision. A vision of a future where hydrogen fuels our journey deeper into the cosmos.

NASA’s commitment to hydrogen is evident in its ongoing research and development efforts. These are aimed at refining hydrogen technologies for future space missions. The quest for more efficient and sustainable energy solutions in space continues. With this in mind, we’ll now shift our focus to the fundamental physical attributes that govern hydrogen’s behavior. We will be diving deeper into the characteristics that influence its storage and diverse applications.

Physical Attributes: Density and Thermal Conductivity of Hydrogen

Hydrogen’s unique physical properties dictate the technologies used to handle and utilize it. Among these critical properties, density and thermal conductivity play pivotal roles. They significantly influence everything from storage solutions to specialized applications.

Density of Hydrogen: A Challenge for Storage

Hydrogen, at standard temperature and pressure, is the least dense gas.

This characteristic presents a major hurdle in storage. Its low volumetric energy density means that a large volume of hydrogen is required to store a given amount of energy.

Implications for Storage Methods

To achieve practical energy storage densities, hydrogen is often compressed or liquefied.

• Compressed hydrogen requires high-pressure tanks, which adds weight and cost.

• Liquefied hydrogen necessitates cryogenic temperatures (-253°C), consuming a substantial amount of energy for cooling and insulation.

Material-based storage methods, like metal hydrides and adsorbents, aim to increase hydrogen density by chemically or physically binding hydrogen to a solid material.

These methods are still under development, striving to achieve optimal storage capacities and release kinetics.

Overcoming Density Limitations

Nanomaterials are emerging as potential game-changers.

They offer high surface areas for adsorption and the ability to tune material properties. This leads to enhanced hydrogen storage capabilities.

Research into novel materials and storage techniques is crucial. It is key to unlocking hydrogen’s potential as a viable energy carrier.

Thermal Conductivity: Enabling Specialized Applications

Hydrogen boasts a high thermal conductivity, surpassing that of many other common gases.

This means it efficiently transfers heat. This property makes it valuable in applications where effective heat dissipation is essential.

Applications in Cooling Systems

Hydrogen gas is employed as a coolant in various industrial processes.

This also includes power generation equipment, where efficient heat removal is critical for performance and longevity.

Its ability to rapidly dissipate heat prevents overheating and ensures stable operation.

Specialized Industrial Uses

In some niche applications, hydrogen’s thermal conductivity is leveraged for specialized purposes.

For example, it can be used in certain types of heat exchangers or sensors.

The specific application dictates the required purity and operating conditions. This ensures optimal heat transfer performance.

So, there you have it! Hopefully, you’ve now got a better grasp on some of the less obvious aspects that are related to the property of hydrogen gas. Now go out there and put that knowledge to good use!