Meaning of the word gas

This article is about the state of matter. For liquified petroleum gas used as an automotive fuel, see autogas. For gasoline («gas»), see gasoline. For the uses of gases, and other meanings, see Gas (disambiguation).

Gas is one of the four fundamental states of matter. The others are solid, liquid, and plasma.^[1]

A pure gas may be made up of individual atoms (e.g. a noble gas like neon), elemental molecules made from one type of atom (e.g. oxygen), or compound molecules made from a variety of atoms (e.g. carbon dioxide). A gas mixture, such as air, contains a variety of pure gases. What distinguishes a gas from liquids and solids is the vast separation of the individual gas particles. This separation usually makes a colourless gas invisible to the human observer.

The gaseous state of matter occurs between the liquid and plasma states,^[2] the latter of which provides the upper temperature boundary for gases. Bounding the lower end of the temperature scale lie degenerative quantum gases^[3] which are gaining increasing attention.^[4]
High-density atomic gases super-cooled to very low temperatures are classified by their statistical behavior as either Bose gases or Fermi gases. For a comprehensive listing of these exotic states of matter see list of states of matter.

Elemental gases[edit]

The only chemical elements that are stable diatomic homonuclear molecular gases at STP are hydrogen (H₂), nitrogen (N₂), oxygen (O₂), and two halogens: fluorine (F₂) and chlorine (Cl₂). When grouped together with the monatomic noble gases – helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn) – these gases are referred to as «elemental gases».

Etymology[edit]

The word gas was first used by the early 17th-century Flemish chemist Jan Baptist van Helmont.^[5] He identified carbon dioxide, the first known gas other than air.^[6] Van Helmont’s word appears to have been simply a phonetic transcription of the Ancient Greek word χάος ‘chaos‘ – the g in Dutch being pronounced like ch in «loch» (voiceless velar fricative, ) – in which case Van Helmont was simply following the established alchemical usage first attested in the works of Paracelsus. According to Paracelsus’s terminology, chaos meant something like ‘ultra-rarefied water‘.^[7]

An alternative story is that Van Helmont’s term was derived from «gahst (or geist), which signifies a ghost or spirit».^[8] That story is given no credence by the editors of the Oxford English Dictionary.^[9] In contrast, the French-American historian Jacques Barzun speculated that Van Helmont had borrowed the word from the German Gäscht, meaning the froth resulting from fermentation.^[10]

Physical characteristics[edit]

Because most gases are difficult to observe directly, they are described through the use of four physical properties or macroscopic characteristics: pressure, volume, number of particles (chemists group them by moles) and temperature. These four characteristics were repeatedly observed by scientists such as Robert Boyle, Jacques Charles, John Dalton, Joseph Gay-Lussac and Amedeo Avogadro for a variety of gases in various settings. Their detailed studies ultimately led to a mathematical relationship among these properties expressed by the ideal gas law (see simplified models section below).

Gas particles are widely separated from one another, and consequently, have weaker intermolecular bonds than liquids or solids. These intermolecular forces result from electrostatic interactions between gas particles. Like-charged areas of different gas particles repel, while oppositely charged regions of different gas particles attract one another; gases that contain permanently charged ions are known as plasmas. Gaseous compounds with polar covalent bonds contain permanent charge imbalances and so experience relatively strong intermolecular forces, although the molecule while the compound’s net charge remains neutral. Transient, randomly induced charges exist across non-polar covalent bonds of molecules and electrostatic interactions caused by them are referred to as Van der Waals forces. The interaction of these intermolecular forces varies within a substance which determines many of the physical properties unique to each gas.^[11][12] A comparison of boiling points for compounds formed by ionic and covalent bonds leads us to this conclusion.^[13] The drifting smoke particles in the image provides some insight into low-pressure gas behavior.

Compared to the other states of matter, gases have low density and viscosity. Pressure and temperature influence the particles within a certain volume. This variation in particle separation and speed is referred to as compressibility. This particle separation and size influences optical properties of gases as can be found in the following list of refractive indices. Finally, gas particles spread apart or diffuse in order to homogeneously distribute themselves throughout any container.

Macroscopic view of gases[edit]

When observing a gas, it is typical to specify a frame of reference or length scale. A larger length scale corresponds to a macroscopic or global point of view of the gas. This region (referred to as a volume) must be sufficient in size to contain a large sampling of gas particles. The resulting statistical analysis of this sample size produces the «average» behavior (i.e. velocity, temperature or pressure) of all the gas particles within the region. In contrast, a smaller length scale corresponds to a microscopic or particle point of view.

Macroscopically, the gas characteristics measured are either in terms of the gas particles themselves (velocity, pressure, or temperature) or their surroundings (volume). For example, Robert Boyle studied pneumatic chemistry for a small portion of his career. One of his experiments related the macroscopic properties of pressure and volume of a gas. His experiment used a J-tube manometer which looks like a test tube in the shape of the letter J. Boyle trapped an inert gas in the closed end of the test tube with a column of mercury, thereby making the number of particles and the temperature constant. He observed that when the pressure was increased in the gas, by adding more mercury to the column, the trapped gas’ volume decreased (this is known as an inverse relationship). Furthermore, when Boyle multiplied the pressure and volume of each observation, the product was constant. This relationship held for every gas that Boyle observed leading to the law, (PV=k), named to honor his work in this field.

There are many mathematical tools available for analyzing gas properties. As gases are subjected to extreme conditions, these tools become more complex, from the Euler equations for inviscid flow to the Navier–Stokes equations^[14] that fully account for viscous effects. These equations are adapted to the conditions of the gas system in question. Boyle’s lab equipment allowed the use of algebra to obtain his analytical results. His results were possible because he was studying gases in relatively low pressure situations where they behaved in an «ideal» manner. These ideal relationships apply to safety calculations for a variety of flight conditions on the materials in use. The high technology equipment in use today was designed to help us safely explore the more exotic operating environments where the gases no longer behave in an «ideal» manner. This advanced math, including statistics and multivariable calculus, makes possible the solution to such complex dynamic situations as space vehicle reentry. An example is the analysis of the space shuttle reentry pictured to ensure the material properties under this loading condition are appropriate. In this flight regime, the gas is no longer behaving ideally.

Pressure[edit]

The symbol used to represent pressure in equations is «p» or «P» with SI units of pascals.

When describing a container of gas, the term pressure (or absolute pressure) refers to the average force per unit area that the gas exerts on the surface of the container. Within this volume, it is sometimes easier to visualize the gas particles moving in straight lines until they collide with the container (see diagram at top of the article). The force imparted by a gas particle into the container during this collision is the change in momentum of the particle.^[15] During a collision only the normal component of velocity changes. A particle traveling parallel to the wall does not change its momentum. Therefore, the average force on a surface must be the average change in linear momentum from all of these gas particle collisions.

Pressure is the sum of all the normal components of force exerted by the particles impacting the walls of the container divided by the surface area of the wall.

Temperature[edit]

The symbol used to represent temperature in equations is T with SI units of kelvins.

The speed of a gas particle is proportional to its absolute temperature. The volume of the balloon in the video shrinks when the trapped gas particles slow down with the addition of extremely cold nitrogen. The temperature of any physical system is related to the motions of the particles (molecules and atoms) which make up the [gas] system.^[16] In statistical mechanics, temperature is the measure of the average kinetic energy stored in a molecule (also known as the thermal energy). The methods of storing this energy are dictated by the degrees of freedom of the molecule itself (energy modes). Thermal (kinetic) energy added to a gas or liquid (an endothermic process) produces translational, rotational, and vibrational motion. In contrast, a solid can only increase its internal energy by exciting additional vibrational modes, as the crystal lattice structure prevents both translational and rotational motion. These heated gas molecules have a greater speed range (wider distribution of speeds) with a higher average or mean speed. The variance of this distribution is due to the speeds of individual particles constantly varying, due to repeated collisions with other particles. The speed range can be described by the Maxwell–Boltzmann distribution. Use of this distribution implies ideal gases near thermodynamic equilibrium for the system of particles being considered.

Specific volume[edit]

The symbol used to represent specific volume in equations is «v» with SI units of cubic meters per kilogram.

The symbol used to represent volume in equations is «V» with SI units of cubic meters.

When performing a thermodynamic analysis, it is typical to speak of intensive and extensive properties. Properties which depend on the amount of gas (either by mass or volume) are called extensive properties, while properties that do not depend on the amount of gas are called intensive properties. Specific volume is an example of an intensive property because it is the ratio of volume occupied by a unit of mass of a gas that is identical throughout a system at equilibrium.^[17] 1000 atoms a gas occupy the same space as any other 1000 atoms for any given temperature and pressure. This concept is easier to visualize for solids such as iron which are incompressible compared to gases. However, volume itself — not specific — is an extensive property.

Density[edit]

The symbol used to represent density in equations is ρ (rho) with SI units of kilograms per cubic meter. This term is the reciprocal of specific volume.

Since gas molecules can move freely within a container, their mass is normally characterized by density. Density is the amount of mass per unit volume of a substance, or the inverse of specific volume. For gases, the density can vary over a wide range because the particles are free to move closer together when constrained by pressure or volume. This variation of density is referred to as compressibility. Like pressure and temperature, density is a state variable of a gas and the change in density during any process is governed by the laws of thermodynamics. For a static gas, the density is the same throughout the entire container. Density is therefore a scalar quantity. It can be shown by kinetic theory that the density is inversely proportional to the size of the container in which a fixed mass of gas is confined. In this case of a fixed mass, the density decreases as the volume increases.

Microscopic view of gases[edit]

If one could observe a gas under a powerful microscope, one would see a collection of particles without any definite shape or volume that are in more or less random motion. These gas particles only change direction when they collide with another particle or with the sides of the container. This microscopic view of gas is well-described by statistical mechanics, but it can be described by many different theories. The kinetic theory of gases, which makes the assumption that these collisions are perfectly elastic, does not account for intermolecular forces of attraction and repulsion.

Kinetic theory of gases[edit]

Kinetic theory provides insight into the macroscopic properties of gases by considering their molecular composition and motion. Starting with the definitions of momentum and kinetic energy,^[18] one can use the conservation of momentum and geometric relationships of a cube to relate macroscopic system properties of temperature and pressure to the microscopic property of kinetic energy per molecule. The theory provides averaged values for these two properties.

The kinetic theory of gases can help explain how the system (the collection of gas particles being considered) responds to changes in temperature, with a corresponding change in kinetic energy.

For example: Imagine you have a sealed container of a fixed-size (a constant volume), containing a fixed-number of gas particles; starting from absolute zero (the theoretical temperature at which atoms or molecules have no thermal energy, i.e. are not moving or vibrating), you begin to add energy to the system by heating the container, so that energy transfers to the particles inside. Once their internal energy is above zero-point energy, meaning their kinetic energy (also known as thermal energy) is non-zero, the gas particles will begin to move around the container. As the box is further heated (as more energy is added), the individual particles increase their average speed as the system’s total internal energy increases. The higher average-speed of all the particles leads to a greater rate at which collisions happen (i.e. greater number of collisions per unit of time), between particles and the container, as well as between the particles themselves.

The macroscopic, measurable quantity of pressure, is the direct result of these microscopic particle collisions with the surface, over which, individual molecules exert a small force, each contributing to the total force applied within a specific area. (Read «Pressure» in the above section «Macroscopic view of gases«.)

Likewise, the macroscopically measurable quantity of temperature, is a quantification of the overall amount of motion, or kinetic energy that the particles exhibit. (Read «Temperature» in the above section «Macroscopic view of gases«.)

Thermal motion and statistical mechanics[edit]

In the kinetic theory of gases, kinetic energy is assumed to purely consist of linear translations according to a speed distribution of particles in the system. However, in real gases and other real substances, the motions which define the kinetic energy of a system (which collectively determine the temperature), are much more complex than simple linear translation due to the more complex structure of molecules, compared to single atoms which act similarly to point-masses. In real thermodynamic systems, quantum phenomena play a large role in determining thermal motions. The random, thermal motions (kinetic energy) in molecules is a combination of a finite set of possible motions including translation, rotation, and vibration. This finite range of possible motions, along with the finite set of molecules in the system, leads to a finite number of microstates within the system; we call the set of all microstates an ensemble. Specific to atomic or molecular systems, we could potentially have three different kinds of ensemble, depending on the situation: microcanonical ensemble, canonical ensemble, or grand canonical ensemble. Specific combinations of microstates within an ensemble are how we truly define macrostate of the system (temperature, pressure, energy, etc.). In order to do that, we must first count all microstates though use of a partition function. The use of statistical mechanics and the partition function is an important tool throughout all of physical chemistry, because it is the key to connection between the microscopic states of a system and the macroscopic variables which we can measure, such as temperature, pressure, heat capacity, internal energy, enthalpy, and entropy, just to name a few. (Read: Partition function Meaning and significance)

Using the partition function to find the energy of a molecule, or system of molecules, can sometimes be approximated by the Equipartition theorem, which greatly-simplifies calculation. However, this method assumes all molecular degrees of freedom are equally populated, and therefore equally utilized for storing energy within the molecule. It would imply that internal energy changes linearly with temperature, which is not the case. This ignores the fact that heat capacity changes with temperature, due to certain degrees of freedom being unreachable (a.k.a. «frozen out») at lower temperatures. As internal energy of molecules increases, so does the ability to store energy within additional degrees of freedom. As more degrees of freedom become available to hold energy, this causes the molar heat capacity of the substance to increase.^[19]

Brownian motion[edit]

Brownian motion is the mathematical model used to describe the random movement of particles suspended in a fluid. The gas particle animation, using pink and green particles, illustrates how this behavior results in the spreading out of gases (entropy). These events are also described by particle theory.

Since it is at the limit of (or beyond) current technology to observe individual gas particles (atoms or molecules), only theoretical calculations give suggestions about how they move, but their motion is different from Brownian motion because Brownian motion involves a smooth drag due to the frictional force of many gas molecules, punctuated by violent collisions of an individual (or several) gas molecule(s) with the particle. The particle (generally consisting of millions or billions of atoms) thus moves in a jagged course, yet not so jagged as would be expected if an individual gas molecule were examined.

Intermolecular forces — the primary difference between Real and Ideal gases[edit]

Forces between two or more molecules or atoms, either attractive or repulsive, are called intermolecular forces. Intermolecular forces are experienced by molecules when they are within physical proximity of one another. These forces are very important for properly modeling molecular systems, as to accurately predict the microscopic behavior of molecules in any system, and therefore, are necessary for accurately predicting the physical properties of gases (and liquids) across wide variations in physical conditions.

Arising from the study of physical chemistry, one of the most prominent intermolecular forces throughout physics, are van der Waals forces. Van der Waals forces play a key role in determining nearly all physical properties of fluids such as viscosity, flow rate, and gas dynamics (see physical characteristics section). The van der Waals interactions between gas molecules, is the reason why modeling a «real gas» is more mathematically difficult than an «ideal gas». Ignoring these proximity-dependent forces allows a real gas to be treated like an ideal gas, which greatly simplifies calculation.

The intermolecular attractions and repulsions between two gas molecules are dependent on the amount of distance between them. The combined attractions and repulsions are well-modelled by the Lennard-Jones potential, which is one of the most extensively studied of all interatomic potentials describing the potential energy of molecular systems. The Lennard-Jones potential between molecules can be broken down into two separate components: a long-distance attraction due to the London dispersion force, and a short-range repulsion due to electron-electron exchange interaction (which is related to the Pauli exclusion principle).

When two molecules are relatively distant (meaning they have a high potential energy), they experience a weak attracting force, causing them to move toward each other, lowering their potential energy. However, if the molecules are too far away, then they would not experience attractive force of any significance. Additionally, if the molecules get too close then they will collide, and experience a very high repulsive force (modelled by Hard spheres) which is a much stronger force than the attractions, so that any attraction due to proximity is disregarded.

As two molecules approach each other, from a distance that is neither too-far, nor too-close, their attraction increases as the magnitude of their potential energy increases (becoming more negative), and lowers their total internal energy.^[20] The attraction causing the molecules to get closer, can only happen if the molecules remain in proximity for the duration of time it takes to physically move closer. Therefore, the attractive forces are strongest when the molecules move at low speeds. This means that the attraction between molecules is significant when gas temperatures is low. However, if you were to isothermally compress this cold gas into a small volume, forcing the molecules into close proximity, and raising the pressure, the repulsions will begin to dominate over the attractions, as the rate at which collisions are happening will increase significantly. Therefore, at low temperatures, and low pressures, attraction is the dominant intermolecular interaction.

If two molecules are moving at high speeds, in arbitrary directions, along non-intersecting paths, then they will not spend enough time in proximity to be affected by the attractive London-dispersion force. If the two molecules collide, they are moving too fast and their kinetic energy will be much greater than any attractive potential energy, so they will only experience repulsion upon colliding. Thus, attractions between molecules can be neglected at high temperatures due to high speeds. At high temperatures, and high pressures, repulsion is the dominant intermolecular interaction.

Accounting for the above stated effects which cause these attractions and repulsions, real gases, delineate from the ideal gas model by the following generalization:^[21]

• At low temperatures, and low pressures, the volume occupied by a real gas, is less than the volume predicted by the ideal gas law.
• At high temperatures, and high pressures, the volume occupied by a real gas, is greater than the volume predicted by the ideal gas law.

Mathematical models[edit]

An equation of state (for gases) is a mathematical model used to roughly describe or predict the state properties of a gas. At present, there is no single equation of state that accurately predicts the properties of all gases under all conditions. Therefore, a number of much more accurate equations of state have been developed for gases in specific temperature and pressure ranges. The «gas models» that are most widely discussed are «perfect gas», «ideal gas» and «real gas». Each of these models has its own set of assumptions to facilitate the analysis of a given thermodynamic system.^[22] Each successive model expands the temperature range of coverage to which it applies.

Ideal and perfect gas[edit]

The equation of state for an ideal or perfect gas is the ideal gas law and reads

where P is the pressure, V is the volume, n is amount of gas (in mol units), R is the universal gas constant, 8.314 J/(mol K), and T is the temperature. Written this way, it is sometimes called the «chemist’s version», since it emphasizes the number of molecules n. It can also be written as

where is the specific gas constant for a particular gas, in units J/(kg K), and ρ = m/V is density. This notation is the «gas dynamicist’s» version, which is more practical in modeling of gas flows involving acceleration without chemical reactions.

The ideal gas law does not make an assumption about the specific heat of a gas. In the most general case, the specific heat is a function of both temperature and pressure. If the pressure-dependence is neglected (and possibly the temperature-dependence as well) in a particular application, sometimes the gas is said to be a perfect gas, although the exact assumptions may vary depending on the author and/or field of science.

For an ideal gas, the ideal gas law applies without restrictions on the specific heat. An ideal gas is a simplified «real gas» with the assumption that the compressibility factor Z is set to 1 meaning that this pneumatic ratio remains constant. A compressibility factor of one also requires the four state variables to follow the ideal gas law.

This approximation is more suitable for applications in engineering although simpler models can be used to produce a «ball-park» range as to where the real solution should lie. An example where the «ideal gas approximation» would be suitable would be inside a combustion chamber of a jet engine.^[23] It may also be useful to keep the elementary reactions and chemical dissociations for calculating emissions.

Real gas[edit]

Each one of the assumptions listed below adds to the complexity of the problem’s solution. As the density of a gas increases with rising pressure, the intermolecular forces play a more substantial role in gas behavior which results in the ideal gas law no longer providing «reasonable» results. At the upper end of the engine temperature ranges (e.g. combustor sections – 1300 K), the complex fuel particles absorb internal energy by means of rotations and vibrations that cause their specific heats to vary from those of diatomic molecules and noble gases. At more than double that temperature, electronic excitation and dissociation of the gas particles begins to occur causing the pressure to adjust to a greater number of particles (transition from gas to plasma).^[24] Finally, all of the thermodynamic processes were presumed to describe uniform gases whose velocities varied according to a fixed distribution. Using a non-equilibrium situation implies the flow field must be characterized in some manner to enable a solution. One of the first attempts to expand the boundaries of the ideal gas law was to include coverage for different thermodynamic processes by adjusting the equation to read pVⁿ = constant and then varying the n through different values such as the specific heat ratio, γ.

Real gas effects include those adjustments made to account for a greater range of gas behavior:

• Compressibility effects (Z allowed to vary from 1.0)
• Variable heat capacity (specific heats vary with temperature)
• Van der Waals forces (related to compressibility, can substitute other equations of state)
• Non-equilibrium thermodynamic effects
• Issues with molecular dissociation and elementary reactions with variable composition.

For most applications, such a detailed analysis is excessive. Examples where real gas effects would have a significant impact would be on the Space Shuttle re-entry where extremely high temperatures and pressures were present or the gases produced during geological events as in the image of the 1990 eruption of Mount Redoubt.

Permanent gas[edit]

Permanent gas is a term used for a gas which has a critical temperature below the range of normal human-habitable temperatures and therefore cannot be liquefied by pressure within this range. Historically such gases were thought to be impossible to liquefy and would therefore permanently remain in the gaseous state. The term is relevant to ambient temperature storage and transport of gases at high pressure.^[25]

Historical research[edit]

Boyle’s law[edit]

Boyle’s law was perhaps the first expression of an equation of state. In 1662 Robert Boyle performed a series of experiments employing a J-shaped glass tube, which was sealed on one end. Mercury was added to the tube, trapping a fixed quantity of air in the short, sealed end of the tube. Then the volume of gas was carefully measured as additional mercury was added to the tube. The pressure of the gas could be determined by the difference between the mercury level in the short end of the tube and that in the long, open end. The image of Boyle’s equipment shows some of the exotic tools used by Boyle during his study of gases.

Through these experiments, Boyle noted that the pressure exerted by a gas held at a constant temperature varies inversely with the volume of the gas.^[26] For example, if the volume is halved, the pressure is doubled; and if the volume is doubled, the pressure is halved. Given the inverse relationship between pressure and volume, the product of pressure (P) and volume (V) is a constant (k) for a given mass of confined gas as long as the temperature is constant. Stated as a formula, thus is:

Because the before and after volumes and pressures of the fixed amount of gas, where the before and after temperatures are the same both equal the constant k, they can be related by the equation:

Charles’s law[edit]

In 1787, the French physicist and balloon pioneer, Jacques Charles, found that oxygen, nitrogen, hydrogen, carbon dioxide, and air expand to the same extent over the same 80 kelvin interval. He noted that, for an ideal gas at constant pressure, the volume is directly proportional to its temperature:

Gay-Lussac’s law[edit]

In 1802, Joseph Louis Gay-Lussac published results of similar, though more extensive experiments.^[27] Gay-Lussac credited Charles’ earlier work by naming the law in his honor. Gay-Lussac himself is credited with the law describing pressure, which he found in 1809. It states that the pressure exerted on a container’s sides by an ideal gas is proportional to its temperature.

Avogadro’s law[edit]

In 1811, Amedeo Avogadro verified that equal volumes of pure gases contain the same number of particles. His theory was not generally accepted until 1858 when another Italian chemist Stanislao Cannizzaro was able to explain non-ideal exceptions. For his work with gases a century prior, the physical constant that bears his name (the Avogadro constant) is the number of atoms per mole of elemental carbon-12 (6.022×10²³ mol⁻¹). This specific number of gas particles, at standard temperature and pressure (ideal gas law) occupies 22.40 liters, which is referred to as the molar volume.

Avogadro’s law states that the volume occupied by an ideal gas is proportional to the amount of substance in the volume. This gives rise to the molar volume of a gas, which at STP is 22.4 dm³/mol (liters per mole). The relation is given by

where n is the amount of substance of gas (the number of molecules divided by the Avogadro constant).

Dalton’s law[edit]

In 1801, John Dalton published the law of partial pressures from his work with ideal gas law relationship: The pressure of a mixture of non reactive gases is equal to the sum of the pressures of all of the constituent gases alone. Mathematically, this can be represented for n species as:

Pressure_total = Pressure₁ + Pressure₂ + … + Pressure_n

The image of Dalton’s journal depicts symbology he used as shorthand to record the path he followed. Among his key journal observations upon mixing unreactive «elastic fluids» (gases) were the following:^[28]

• Unlike liquids, heavier gases did not drift to the bottom upon mixing.
• Gas particle identity played no role in determining final pressure (they behaved as if their size was negligible).

Special topics[edit]

Compressibility[edit]

Thermodynamicists use this factor (Z) to alter the ideal gas equation to account for compressibility effects of real gases. This factor represents the ratio of actual to ideal specific volumes. It is sometimes referred to as a «fudge-factor» or correction to expand the useful range of the ideal gas law for design purposes. Usually this Z value is very close to unity. The compressibility factor image illustrates how Z varies over a range of very cold temperatures.

Reynolds number[edit]

In fluid mechanics, the Reynolds number is the ratio of inertial forces (v_sρ) to viscous forces (μ/L). It is one of the most important dimensionless numbers in fluid dynamics and is used, usually along with other dimensionless numbers, to provide a criterion for determining dynamic similitude. As such, the Reynolds number provides the link between modeling results (design) and the full-scale actual conditions. It can also be used to characterize the flow.

Viscosity[edit]

Viscosity, a physical property, is a measure of how well adjacent molecules stick to one another. A solid can withstand a shearing force due to the strength of these sticky intermolecular forces. A fluid will continuously deform when subjected to a similar load. While a gas has a lower value of viscosity than a liquid, it is still an observable property. If gases had no viscosity, then they would not stick to the surface of a wing and form a boundary layer. A study of the delta wing in the Schlieren image reveals that the gas particles stick to one another (see Boundary layer section).

Turbulence[edit]

In fluid dynamics, turbulence or turbulent flow is a flow regime characterized by chaotic, stochastic property changes. This includes low momentum diffusion, high momentum convection, and rapid variation of pressure and velocity in space and time. The satellite view of weather around Robinson Crusoe Islands illustrates one example.

Boundary layer[edit]

Particles will, in effect, «stick» to the surface of an object moving through it. This layer of particles is called the boundary layer. At the surface of the object, it is essentially static due to the friction of the surface. The object, with its boundary layer is effectively the new shape of the object that the rest of the molecules «see» as the object approaches. This boundary layer can separate from the surface, essentially creating a new surface and completely changing the flow path. The classical example of this is a stalling airfoil. The delta wing image clearly shows the boundary layer thickening as the gas flows from right to left along the leading edge.

Maximum entropy principle[edit]

As the total number of degrees of freedom approaches infinity, the system will be found in the macrostate that corresponds to the highest multiplicity. In order to illustrate this principle, observe the skin temperature of a frozen metal bar. Using a thermal image of the skin temperature, note the temperature distribution on the surface. This initial observation of temperature represents a «microstate». At some future time, a second observation of the skin temperature produces a second microstate. By continuing this observation process, it is possible to produce a series of microstates that illustrate the thermal history of the bar’s surface. Characterization of this historical series of microstates is possible by choosing the macrostate that successfully classifies them all into a single grouping.

Thermodynamic equilibrium[edit]

When energy transfer ceases from a system, this condition is referred to as thermodynamic equilibrium. Usually, this condition implies the system and surroundings are at the same temperature so that heat no longer transfers between them. It also implies that external forces are balanced (volume does not change), and all chemical reactions within the system are complete. The timeline varies for these events depending on the system in question. A container of ice allowed to melt at room temperature takes hours, while in semiconductors the heat transfer that occurs in the device transition from an on to off state could be on the order of a few nanoseconds.

See also[edit]

• Greenhouse gas
• List of gases
• Natural gas
• Volcanic gas
• Breathing gas
• Wind

Notes[edit]

References[edit]

• Anderson, John D. (1984). Fundamentals of Aerodynamics. McGraw-Hill Higher Education. ISBN 978-0-07-001656-9.
• John, James (1984). Gas Dynamics. Allyn and Bacon. ISBN 978-0-205-08014-4.
• McPherson, William; Henderson, William (1917). An Elementary study of chemistry.

Further reading[edit]

• Philip Hill and Carl Peterson. Mechanics and Thermodynamics of Propulsion: Second Edition Addison-Wesley, 1992. ISBN 0-201-14659-2
• National Aeronautics and Space Administration (NASA). Animated Gas Lab. Accessed February 2008.
• Georgia State University. HyperPhysics. Accessed February 2008.
• Antony Lewis WordWeb. Accessed February 2008.
• Northwestern Michigan College The Gaseous State. Accessed February 2008.
• Lewes, Vivian Byam; Lunge, Georg (1911). «Gas» . Encyclopædia Britannica. Vol. 11 (11th ed.). p. 481–493.

• Defenition of the word gas

  • A substance that continues to occupy in a continuous manner the whole of the space in which it is placed, however large or small this place is made, the temperature remaining constant.
  • A fuel for internal combustion engines consisting essentially of volatile flammable liquid hydrocarbons derived from crude petroleum.
  • To show off.
  • a pedal that controls the throttle valve; «he stepped on the gas»
  • show off
  • a state of excessive gas in the alimentary canal
  • the state of matter distinguished from the solid and liquid states by: relatively low density and viscosity; relatively great expansion and contraction with changes in pressure and temperature; the ability to diffuse readily; and the spontaneous tendency to become distributed uniformly throughout any container
  • a fluid in the gaseous state having neither independent shape nor volume and being able to expand indefinitely
  • attack with gas; subject to gas fumes; «The despot gassed the rebellious tribes»
  • a volatile flammable mixture of hydrocarbons (hexane and heptane and octane etc.) derived from petroleum; used mainly as a fuel in internal-combustion engines
  • a fossil fuel in the gaseous state; used for cooking and heating homes
  • the state of matter distinguished from the solid and liquid states by: relatively low density and viscosity; relatively great expansion and contraction with changes in pressure and temperature; the ability to diffuse readily; and the spontaneous tendency
  • a pedal that controls the throttle valve
  • attack with gas; subject to gas fumes

Synonyms for the word gas

• • accelerator
  • accelerator pedal
  • blow
  • bluster
  • boast
  • brag
  • chat
  • chatter
  • flatulence
  • flatulency
  • gab
  • gas pedal
  • gasconade
  • gasolene
  • gasoline
  • gun
  • natural gas
  • petrol
  • shoot a line
  • swap gossip
  • swash
  • throttle
  • tout
  • vaunt

Similar words in the gas

• • gas
  • gascony
  • gascony’s
  • gaseous
  • gases
  • gash
  • gashed
  • gashes
  • gashing
  • gasket
  • gasket’s
  • gaskets
  • gaslight
  • gaslight’s
  • gaslights
  • gasohol
  • gasoline
  • gasped
  • gasping
  • gasps
  • gassed
  • gasser
  • gasser’s
  • gassier
  • gassiest
  • gassing
  • gassy
  • gastric
  • gastritis
  • gastritis’s
  • gastronomic
  • gastronomical
  • gastronomy
  • gastronomy’s
  • gasworks
  • gasworks’s

Meronymys for the word gas

• • aeroplane
  • airplane
  • auto
  • automobile
  • car
  • machine
  • methane
  • motorcar
  • plane

Hyponyms for the word gas

• • afterdamp
  • air
  • air gas
  • argonon
  • arsine
  • atmosphere
  • atomic number 1
  • atomic number 17
  • atomic number 7
  • atomic number 8
  • atomic number 9
  • blow gas
  • blowing gas
  • bottled gas
  • butane
  • butene
  • butylene
  • chlorine
  • Cl
  • compressed gas
  • crow
  • cyanogen
  • ethene
  • ethylene
  • exhaust
  • exhaust fumes
  • F
  • firedamp
  • fluorine
  • formaldehyde
  • fumes
  • gloat
  • greenhouse emission
  • greenhouse gas
  • H
  • hydrogen
  • ideal gas
  • inert gas
  • inhalant
  • lachrymator
  • lacrimator
  • leaded gasoline
  • leaded petrol
  • liquefied petroleum gas
  • mephitis
  • methanal
  • methane
  • N
  • napalm
  • nitric oxide
  • nitrogen
  • nitrogen dioxide
  • noble gas
  • O
  • oxygen
  • ozone
  • perfect gas
  • phosgene
  • phosphine
  • poison gas
  • producer gas
  • propane
  • propene
  • propylene
  • puff
  • sewer gas
  • sublimate
  • sulfur dioxide
  • sulphur dioxide
  • tear gas
  • teargas
  • triumph
  • unleaded gasoline
  • unleaded petrol
  • water gas

Hypernyms for the word gas

• • amplify
  • assail
  • attack
  • combustible
  • combustible material
  • exaggerate
  • fluid
  • foot lever
  • foot pedal
  • fossil fuel
  • fuel
  • hydrocarbon
  • hyerbolise
  • hyperbolise
  • hyperbolize
  • magnify
  • overdraw
  • overstate
  • pedal
  • physical condition
  • physiological condition
  • physiological state
  • state
  • state of matter
  • treadle

See other words

• • What is archiv
  • The definition of architektur
  • The interpretation of the word elternteil
  • What is meant by fink
  • The lexical meaning eltern
  • The dictionary meaning of the word gambier
  • The grammatical meaning of the word architektin
  • Meaning of the word fingernagel
  • Literal and figurative meaning of the word eloquenz
  • The origin of the word flachwichser
  • Synonym for the word endemie
  • Antonyms for the word aristokrat
  • Homonyms for the word flakon
  • Hyponyms for the word chronometer
  • Holonyms for the word energie
  • Hypernyms for the word flasche
  • Proverbs and sayings for the word aristokratin
  • Translation of the word in other languages arithmetik

English[edit]

Pronunciation[edit]

• enPR: găs, IPA^(key): /ɡæs/
• enPR: găz, IPA^(key): /ɡæz/(regional)
• Rhymes: -æs
• Rhymes: -æz(some speakers)

Etymology 1[edit]

Borrowed from Dutch gas, coined by chemist Jan Baptist van Helmont in Ortus Medicinae. Derived from Ancient Greek χάος (kháos, “chasm, void, empty space”); perhaps also inspired by geest (“breath, vapour, spirit”). Doublet of chaos. First attested in 1648.

Noun[edit]

gas (countable and uncountable, plural gases or gasses)

1. (uncountable, chemistry) Matter in an intermediate state between liquid and plasma that can be contained only if it is fully surrounded by a solid (or in a bubble of liquid, or held together by gravitational pull); it can condense into a liquid, or can (rarely) become a solid directly by deposition.

   • 2013 July–August, Lee S. Langston, “The Adaptable Gas Turbine”, in American Scientist‎^[1]:

     Turbines have been around for a long time—windmills and water wheels are early examples. The name comes from the Latin turbo, meaning vortex, and thus the defining property of a turbine is that a fluid or gas turns the blades of a rotor, which is attached to a shaft that can perform useful work.

   A lot of gas had escaped from the cylinder.

   Synonyms: vapor, vapour

   1. (uncountable) A flammable gaseous hydrocarbon or hydrocarbon mixture used as a fuel, e.g. for cooking, heating, electricity generation or as a fuel in internal combustion engines in vehicles, especially natural gas.

      Gas-fired power stations have largely replaced coal-burning ones.

   2. (uncountable, military) Poison gas.

      The artillery fired gas shells into the enemy trenches.

2. (countable, chemistry) A chemical element or compound in such a state.

   The atmosphere is made up of a number of different gases.

3. (countable) A hob on a gas cooker.

   She turned the gas on, put the potatoes on, then lit the oven.

4. (uncountable) Methane or other waste gases trapped in one’s belly as a result of the digestive process; flatus.

   Synonym: wind

   My tummy hurts so bad – I have gas.

   • 2008, Nicholas Drayson, A Guide to the Birds of East Africa, page 72:

     But anyone with that many large brown birds aroost in his cranium and that much gas in his bottom was clearly not a well person.

5. (slang) A humorous or entertaining event or person.

   • 1963 May, Gloria Steinem, “A Bunny’s Tale”, in Show Magazine‎^[2], archived from the original on 2017-10-04:

     Two more girls came in, one in bright pink stretch pants and the other in purple. “Man this place is a gas,” said pink.

   • 1971, Marc Bolan (lyrics and music), “Life’s a Gas”, in Electric Warrior, performed by T. Rex:

     No it really doesn’t matter at all / Life’s a gas / I hope it’s going to last

   • 1978, “Heart of Glass”, in Parallel Lines, performed by Blondie:

     Once I had a love and it was a gas / Soon turned out had a heart of glass

   • 1979, “Belsen Was a Gas”, in The Great Rock ‘n’ Roll Swindle, performed by Sex Pistols:

     Be a man, Be a man / Belsen was a gas / Be a man, kill someone

   • 2011 October 11, “Jumping Jack Flash (Live 1973)”, in Brussels Affair (Live 1973)‎^[3], performed by The Rolling Stones:

     One two! I was born in a cross-fire hurricane. And I howled at the maw in the drivin’ rain. But it’s all right now, in fact, it’s a gas. But it’s all right. I’m Jumpin’ Jack Flash. It’s a gas, gas, gas.

6. (slang) Frothy or boastful talk; chatter.
7. (baseball) A fastball.

   The closer threw him nothing but gas.

8. (medicine, colloquial) Arterial or venous blood gas.
9. (slang, uncountable) Marijuana, typically of high quality.

Derived terms[edit]

Translations[edit]

See also[edit]

• fluid
• liquid
• solid

Verb[edit]

gas (third-person singular simple present gases or gasses, present participle gassing, simple past and past participle gassed)

1. (transitive) To attack or kill with poison gas.

   The Nazis gassed millions of Jews during the Holocaust.

   He never fully recovered after he was gassed on the Western Front.

2. (intransitive, slang) To talk in a boastful or vapid way; chatter.

   • 1899, Stephen Crane, chapter 1, in Twelve O’Clock:

     […] (it was the town’s humour to be always gassing of phantom investors who were likely to come any moment and pay a thousand prices for everything) — “ […] Them rich fellers, they don’t make no bad breaks with their money. […] ”

   • 1955, C. S. Lewis, The Magician’s Nephew, Collins, 1998, Chapter 3,

     «Well don’t keep on gassing about it,» said Digory.

3. (transitive, slang) To impose upon by talking boastfully.

   • 2018 September 14, “Don’t Gas Me”, in Don’t Gas Me‎^[4], performed by Dizzy Rascal:

     I went shop and the boss man said «Don’t pay me it’s fine» and I said …(whaaat): «You ain’t gotta gas, I’m gas fam» ( don’t gas me), «You ain’t gotta gas, I’m gas fam».

4. (intransitive) To emit gas.

   The battery cell was gassing.

5. (transitive) To impregnate with gas.

   to gas lime with chlorine in the manufacture of bleaching powder

6. (transitive) To singe, as in a gas flame, so as to remove loose fibers.

   to gas thread

Translations[edit]

Etymology 2[edit]

Clipping of gasoline.

Noun[edit]

gas (countable and uncountable, plural gases or gasses)

1. (uncountable, Canada, US) Gasoline, a light derivative of petroleum used as fuel.

   Synonyms: (US) gasoline, (British) petrol, see also Thesaurus:petroleum

2. (uncountable, Canada, US, by extension) Ellipsis of gas pedal.
4. (uncountable, cryptocurrencies) An internal virtual currency used in Ethereum to pay for certain operations, such as blockchain transactions.

   Coordinate term: Ether

   gas fee

   • 2018, Andreas M. Antonopoulos; Gavin Wood, Mastering Ethereum: Building Smart Contracts and DApps‎^[5], O’Reilly Media, →ISBN:

     Gas is the fuel of Ethereum. Gas is not ether–it’s a separate virtual currency with its own exchange rate against ether. Ethereum uses gas to control the amount of resources that transactions can use […]

   • 2021 November 6, Ben Butler, “Australian banks are opening up to cryptocurrency: what does it mean for you?”, in The Guardian‎^[6]:

     The average “gas fee” – transaction cost – of an Ethereum transaction is between US$85 and US $156, according to crypto.com data.

Derived terms[edit]

Translations[edit]

Verb[edit]

gas (third-person singular simple present gases or gasses, present participle gassing, simple past and past participle gassed)

1. (US) To give a vehicle more fuel in order to accelerate it.

   The cops are coming. Gas it!

   Synonyms: hit the gas, step on the gas

2. (US) To fill (a vehicle’s fuel tank) with fuel.

   Synonym: refuel

Derived terms[edit]

• gas and dash, gas-and-dash
• gas and go, gas-and-go
• gas up

Translations[edit]

Etymology 3[edit]

Compare the slang usage of «a gas», above.

Adjective[edit]

gas (comparative gasser, superlative gassest)

1. (slang) Comical, zany; fun, amusing.

   • 2016, Liz Nugent, Lying In Wait, →ISBN, page 113:

     The other models were gas fun, though they were all a bit hoity-toity.

   • 2018 September 14, “Don’t Gas Me”, in Don’t Gas Me‎^[7], performed by Dizzy Rascal:

     I went shop and the boss man said «Don’t pay me it’s fine» and I said …(whaaat): «You ain’t gotta gas, I’m gas fam» ( don’t gas me), «You ain’t gotta gas, I’m gas fam».

   Mary’s new boyfriend is a gas man.

   It was gas when the bird flew into the classroom.

Anagrams[edit]

• AGS, AGs, Ags., GSA, SAG, SGA, Sag, sag

Afrikaans[edit]

Etymology 1[edit]

From Dutch gast.

Noun[edit]

gas (plural gaste)

1. guest

Etymology 2[edit]

From Dutch gas.

Noun[edit]

gas (plural gasse)

1. gas (substance in gaseous phase)

Basque[edit]

Noun[edit]

gas inan

1. gas

Declension[edit]

Derived terms[edit]

• gaseoso

Catalan[edit]

Pronunciation[edit]

• (Balearic, Central, Valencian) IPA^(key): /ˈɡas/

Noun[edit]

gas m (plural gasos)

1. gas

Derived terms[edit]

[edit]

• gasificar
• gasolina

Further reading[edit]

• “gas” in Diccionari de la llengua catalana, segona edició, Institut d’Estudis Catalans.
• “gas”, in Gran Diccionari de la Llengua Catalana, Grup Enciclopèdia Catalana, 2023
• “gas” in Diccionari normatiu valencià, Acadèmia Valenciana de la Llengua.
• “gas” in Diccionari català-valencià-balear, Antoni Maria Alcover and Francesc de Borja Moll, 1962.

Chinese[edit]

Etymology[edit]

From English gas.

Pronunciation[edit]

Noun[edit]

gas

1. (Hong Kong Cantonese) gas (fuel)

Derived terms[edit]

Dutch[edit]

Pronunciation[edit]

• IPA^(key): /ɣɑs/
• Hyphenation: gas
• Rhymes: -ɑs

Etymology 1[edit]

Coined by chemist Jan Baptiste van Helmont in Ortus Medicinae (1648), by way of deliberate similarity to Greek χάος (cháos, “chasm, void, chaos”).

Noun[edit]

gas n (plural gassen, diminutive gasje n)

1. gas
2. liquefied petroleum gas

   Synonyms: autogas, LPG

Derived terms[edit]

Descendants[edit]

• Afrikaans: gas
• → Caribbean Javanese: gas
• → English: gas
• → French: gaz
  • → Moore: gaase
  • → Romanian: gaz
  • → Turkish: gaz
• → German: Gas
• → Saramaccan: gási
• → West Frisian: gas

Etymology 2[edit]

From Middle Dutch gasse (“unpaved street”), from Middle High German gazze, from Old High German gazza, from Proto-Germanic *gatwǭ.

Noun[edit]

gas f (plural gassen, diminutive gasje n)

1. unpaved street

Etymology 3[edit]

See the etymology of the corresponding lemma form.

Verb[edit]

gas

1. first-person singular present indicative of gassen
2. imperative of gassen

Galician[edit]

Noun[edit]

gas m (plural gases)

1. gas

   Synonym: vapor

Derived terms[edit]

• gas nobre

[edit]

• gasoso

Icelandic[edit]

Pronunciation[edit]

• IPA^(key): /kaːs/
• Rhymes: -aːs

Etymology 1[edit]

Borrowed from Dutch gas.

Noun[edit]

gas n (genitive singular gass, nominative plural gös)

1. gas (state of matter)

Declension[edit]

Derived terms[edit]

• táragas

Etymology 2[edit]

Borrowed from French gaze.

Noun[edit]

gas n (genitive singular gass, no plural)

1. gauze

Declension[edit]

Derived terms[edit]

• gasbleia

Anagrams[edit]

• sag

Indonesian[edit]

Etymology[edit]

From Dutch gas (“gas”), a term coined by chemist Jan Baptist van Helmont. Perhaps inspired by geest (“breath, vapour, spirit”) or by chaos (“chaos”), from Ancient Greek χάος (kháos, “chasm, void”).

Pronunciation[edit]

• IPA^(key): [ˈɡas]
• Hyphenation: gas

Noun[edit]

gas (plural gas-gas, first-person possessive gasku, second-person possessive gasmu, third-person possessive gasnya)

1. gas,
   1. (chemistry, physics) Matter in a state intermediate between liquid and plasma that can be contained only if it is fully surrounded by a solid (or in a bubble of liquid) (or held together by gravitational pull); it can condense into a liquid, or can (rarely) become a solid directly.
   2. A flammable gaseous hydrocarbon or hydrocarbon mixture (typically predominantly methane) used as a fuel, e.g. for cooking, heating, electricity generation or as a fuel in internal combustion engines in vehicles.

Derived terms[edit]

Compounds[edit]

Verb[edit]

gas

1. (colloquial) to hit the gas, to accelerate.

   Synonym: mengegas

Further reading[edit]

• “gas” in Kamus Besar Bahasa Indonesia, Jakarta: Language Development and Fostering Agency — Ministry of Education, Culture, Research, and Technology of the Republic Indonesia, 2016.

Interlingua[edit]

Noun[edit]

gas (plural gases)

1. gas

Irish[edit]

Etymology[edit]

(This etymology is missing or incomplete. Please add to it, or discuss it at the Etymology scriptorium.)

Pronunciation[edit]

• (Munster) IPA^(key): [ɡɑsˠ]
• (Connacht, Ulster) IPA^(key): [ɡasˠ]

Noun[edit]

gas m (genitive singular gais, nominative plural gais or gasa)

1. stalk, stem
2. sprig, shoot, frond
3. (figuratively) stripling; scion

Declension[edit]

Derived terms[edit]

Mutation[edit]

Irish mutation
Radical	Lenition	Eclipsis
gas	ghas	ngas
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.

Further reading[edit]

• Ó Dónaill, Niall (1977), “gas”, in Foclóir Gaeilge–Béarla, Dublin: An Gúm, →ISBN
• Entries containing “gas” in English-Irish Dictionary, An Gúm, 1959, by Tomás de Bhaldraithe.
• Entries containing “gas” in New English-Irish Dictionary by Foras na Gaeilge.

Italian[edit]

Pronunciation[edit]

• IPA^(key): /ˈɡas/
• Rhymes: -as
• Hyphenation: gàs

Noun[edit]

gas m (uncountable)

1. gas (state of matter, petroleum)
2. carbon dioxide (in fizzy drinks)
3. petrol

   Synonym: benzina

4. poison gas

[edit]

Further reading[edit]

• gas in Treccani.it – Vocabolario Treccani on line, Istituto dell’Enciclopedia Italiana

Latin[edit]

Etymology[edit]

Coined by chemist Jan Baptist van Helmont (appearing in his Ortus Medicinae as an invariable noun).

Pronunciation[edit]

• (Classical) IPA^(key): /ɡas/, [ɡäs̠]
• (Ecclesiastical) IPA^(key): /ɡas/, [ɡäs]

Noun[edit]

gas n (genitive gasis); third declension

1. (physics) gas (state of matter)

   Synonyms: gasum, gasium

Declension[edit]

Third-declension noun (neuter, imparisyllabic non-i-stem).

Case	Singular	Plural
Nominative	gas	gasa
Genitive	gasis	gasum
Dative	gasī	gasibus
Accusative	gas	gasa
Ablative	gase	gasibus
Vocative	gas	gasa

Naga Pidgin[edit]

Etymology[edit]

Inherited from Assamese গাছ (gas).

Noun[edit]

gas

1. tree

Norman[edit]

Etymology[edit]

From Old French gars, nominative singular form of garçon.

Noun[edit]

gas m (plural gas)

1. (Jersey) chap

Norwegian Bokmål[edit]

Etymology[edit]

From French gaze.

Noun[edit]

gas m (definite singular gasen, indefinite plural gaser, definite plural gasene)

1. gauze

See also[edit]

• gass
• gås

References[edit]

• “gas” in The Bokmål Dictionary.

Norwegian Nynorsk[edit]

Etymology[edit]

From French gaze.

Noun[edit]

gas m (definite singular gasen, indefinite plural gasar, definite plural gasane)

1. gauze

See also[edit]

• gass
• gås

References[edit]

• “gas” in The Nynorsk Dictionary.

Old Saxon[edit]

Alternative forms[edit]

• gōs

Etymology[edit]

From Proto-West Germanic *gans, from Proto-Germanic *gans, from Proto-Indo-European *ǵʰh₂éns.

Noun[edit]

gās f

1. a goose

Declension[edit]

Descendants[edit]

• Low German: Goos

Old Swedish[edit]

Etymology[edit]

From Old Norse gás, from Proto-Germanic *gans.

Noun[edit]

gās f

1. goose

Declension[edit]

Descendants[edit]

• Swedish: gås

Rohingya[edit]

Etymology[edit]

From Sanskrit.

Noun[edit]

gas

1. tree

Romagnol[edit]

Etymology[edit]

From Dutch gas (“gas”), invented by Jan Baptiste van Helmont, from Latin chaos (“chaos”).

Pronunciation[edit]

• IPA^(key): /ɡas/

Noun[edit]

gas m (plural ghës)

1. gas

Serbo-Croatian[edit]

Pronunciation[edit]

• IPA^(key): /ɡâːs/

Noun[edit]

gȃs m (Cyrillic spelling га̑с)

1. (chiefly Bosnia, Serbia or colloquial) gas (state of matter)

   Synonym: (Croatian) plȋn

2. gas (as fuel for combustion engines)
3. (figuratively) acceleration
   • dȁti gȃs — “give gas”: accelerate
4. gas pedal, accelerator

Declension[edit]

Spanish[edit]

Etymology[edit]

Borrowed from Dutch gas, coined by Belgian chemist Jan Baptist van Helmont. Perhaps inspired by Middle Dutch gheest (Modern Dutch geest (“breath, vapour, spirit”), or from Ancient Greek χάος (kháos, “chasm, void”).

Pronunciation[edit]

• IPA^(key): /ˈɡas/ [ˈɡas]
• Rhymes: -as
• Syllabification: gas

Noun[edit]

gas m (plural gases)

1. gas (matter between liquid and plasma)
2. gas (an element or compound in such a state)
3. gas (flammable gas used for combustion)
4. (in the plural) gas (waste gases trapped in one’s belly)

Derived terms[edit]

[edit]

• gasolina

Further reading[edit]

• “gas”, in Diccionario de la lengua española, Vigésima tercera edición, Real Academia Española, 2014

Anagrams[edit]

• ags, Ags

Swedish[edit]

Etymology[edit]

From Dutch gas.

Pronunciation[edit]

• IPA^(key): /ɡɑːs/

Noun[edit]

gas c

1. gas; a state of matter
2. gas; a compound or element in such a state
3. gas; gaseous fuels
4. (plural only: gaser) gas; waste gas
5. gas pedal, acceleration (compare gaspedal (“gas pedal”) and gasa (“accelerate, hit the gas”))

   trampa på gasen

   step on the gas

   gasen i botten

   pedal to the metal

Declension[edit]

Declension of gas
	Singular	Plural
Indefinite	Definite	Indefinite	Definite
Nominative	gas	gasen	gaser	gaserna
Genitive	gas	gasens	gasers	gasernas

Derived terms[edit]

Anagrams[edit]

• ags, asg

Tagalog[edit]

Pronunciation[edit]

• IPA^(key): /ˈɡas/, [ˈɡas]

Etymology 1[edit]

Either from English gas, itself a clipping of gasoline, or a clipping of gasolina.

Alternative forms[edit]

• gaas

Noun[edit]

gas

1. gasoline

   Synonym: gasolina

2. kerosene; petroleum; gas

   Synonym: petrolyo

Derived terms[edit]

Etymology 2[edit]

Either from Spanish gas or English gas, ultimately from Dutch gas.

Noun[edit]

gas

1. gaseous substance; vapor; fume

   Synonyms: singaw, asngaw

Welsh[edit]

Pronunciation[edit]

• IPA^(key): /ɡaːs/

Verb[edit]

gas

1. Soft mutation of cas.

Mutation[edit]

Welsh mutation
radical	soft	nasal	aspirate
cas	gas	nghas	chas
Note: Some of these forms may be hypothetical. Not every possible mutated form of every word actually occurs.

West Frisian[edit]

Etymology[edit]

Borrowed from Dutch gas.

Pronunciation[edit]

• IPA^(key): /ɡɔs/

Noun[edit]

gas n (plural gassen)

1. gas

Further reading[edit]

• “gas”, in Wurdboek fan de Fryske taal (in Dutch), 2011