Gas is a type of matter that has no discernible shape or volume. Gases can be composed of a single element, like hydrogen gas (H2), a compound, like carbon dioxide (CO2), or a mixture of several gases, like air.
One of the four fundamental states of matter is the gaseous state (along with the solid state, the liquid state, and the plasma). Gases are commonly used to describe substances that exist in the gaseous phase.
List of Gases
The most common type of gas is air (the air we breathe is a gas). It is also a mixture of several gases, including nitrogen, oxygen, and carbon dioxide. The following are some examples of gases.
- Carbon Dioxide
- Carbon Monoxide
- Water Vapour
It should be noted that these substances exist in the gaseous phase under standard temperature and pressure conditions (STP). However, if the gas is subjected to sufficient pressure and cooled to a low enough temperature, it can be liquefied.
What is a Gas?
Gases are liquids that exist in the gaseous state. Gases have the following key characteristics:
- Gases do not have a specific volume. They expand to fill the volume of the container in which they are placed.
- Gases have no distinct shape. They take on the shape of the container in which they are placed.
- In the gaseous phase, intermolecular distances are relatively large. This means that the gas particles are separated by relatively large distances.
- The gas particles are in a constant state of random motion. They move around at random and collide with each other and the container’s walls.
- All gases are known to exert pressure on the walls of their containers due to collisions between the gas particles and the container walls.
Frequently Asked Questions – FAQs on Gases
What exactly is an Ideal Gas?
An ideal gas is one in which all collisions between atoms or molecules are perfectly elastic in nature and there are no intermolecular attractive forces between the particles of the gas. An ideal gas’s particles can be imagined as a series of colliding perfectly hard spheres that do not interact with one another. It is important to note that the ideal gas law applies to all ideal gases. The pressure exerted by a gas on the walls of its container, the absolute temperature of the gas, the volume occupied by the gas, the amount of gaseous substance (or the number of moles of gas), and the universal gas constant is all equated by this law.
Which four physical properties of gases are used to express their macroscopic properties?
The four physical properties that are used to express a gas’s macroscopic properties are:
- The amount of space occupied by the gaseous substance
- The pressure exerted by the gaseous substance on the walls of its container
- The gaseous substance’s absolute temperature
- The number of gaseous particles
It is important to note that all gases have these four physical properties in common. The ideal gas law provides this relationship for ideal gases.
Please provide some examples of homonuclear diatomic gases (at STP)
The following are examples of homonuclear diatomic compounds that exist in the gaseous phase under standard temperature and pressure conditions:
- Hydrogen gas (H2)
- Nitrogen gas (N2)
- Oxygen gas (O2)
- Chlorine gas (Cl2)
- Fluorine gas (F2)
Distinguish between real and ideal gas.
Under certain conditions, real gas obeys the laws of gas, whereas ideal gas always obeys the laws of gas. The two gases also differ in terms of molecule volume, how they interact, and so on.
Ideal Gas is a fictitious gas, which means it doesn’t exist in reality. Under all pressure and temperature conditions, it obeys gas laws. An ideal gas contains many minute particles that move randomly in all directions because there is no interparticle interaction.
Real gas, on the other hand, exists in our environment. Real gases obey gas laws only at high temperatures and low pressures. These gases do not behave like ideal gases because their molecules interact with one another.
What exactly do you mean by monatomic, diatomic, and other forms of gases?
Single atoms make up monatomic gases. These gases are created by combining noble gases such as helium, neon, krypton, argon, and radon. Diatomic gases are typically formed by other elements such as oxygen, nitrogen, and hydrogen. A few pure elements combine to form triatomic gases such as ozone (O3). Compounds include many common gases such as carbon dioxide, carbon monoxide, nitrous oxide, propane, and freon.