What is the gaseous state?
A gaseous state is called a state of matter that consists of the grouping of atoms and molecules with little force of attraction to each other or in expansion, which means that they cannot be totally united.
Matter in the gaseous state is called gas. The word gas derives from the Latin voice bye which means "chaos". It was coined by the chemist Jan Baptista van Helmont in the 17th century.
The gaseous state is one of the aggregation states of matter, along with the liquid, solid, plasma and Bose-Einstein states.
Water in the process of evaporation or boiling.
Some examples of matter in the gaseous state are:
- oxygen gas (O2);
- carbon dioxide (CO2);
- natural gas (used as fuel);
- noble gases such as helium (He); argon (Ar); neon (Ne); krypton (Kr); xenon (Xe), radon (Rn) and oganeson (Og).
- nitrogen (N2);
- water steam;
- tear gas;
- smoke from chimneys and campfires;
- smoke given off by matches;
- refrigerant gas.
Water is the only element that can be found in all states of aggregation of matter naturally (solid, liquid and gaseous).
Characteristics of the gaseous state
Different gases in their containers.
In the gaseous state, the energy of separation between molecules and atoms exceeds the force of attraction between them, which gives rise to a series of characteristics or properties of gases.
- Gases contain fewer particles than liquids and solids.
- The particles are widely separated from each other, so their interaction is little.
- The particles are in constant and disorderly motion.
- Gases have no definite shape or volume.
- When there are collisions between particles, they change direction and speed in a chaotic way, which increases their distance and the volume of the gas.
- Most gases are intangible, colorless, and tasteless.
- The gases can occupy all the volume that they have available.
- Gases can be compressed into the shape of their container.
Changes of state of gaseous matter
Changes of state of gaseous matter. Note also the separation between particles according to the state of matter.
According to the temperature and pressure variables, transformation processes of matter can be generated from one state of aggregation or another. The changes of matter that involve the gaseous state are the following:
Condensation or liquefaction
It is the passage from the gaseous state to the liquid state. It occurs when a gas is subjected to a drop in temperature, which reduces the movement of the particles and encourages them to contract together until they become liquid. We can point out two everyday examples with water: 1) when clouds turn into precipitation. 2) when a glass with a cold drink produces drops of water on the outside by condensing the hot air from the atmosphere.
Evaporation or boiling
It is the transformation from the liquid state to the gaseous state. It occurs when a liquid is subjected to an increase in temperature until it reaches the boiling point. An example can be seen when the water boils in the pan until it evaporates.
It is the change from the solid state to the gaseous state without having to go through the liquid state. Sublimation occurs thanks to temperatures so extreme that they do not allow the formation of liquid. An example of sublimation is found in dry ice that is released into vapor without going through the liquid state.
Reverse sublimation or deposition
It is the change from the solid state to the gaseous state without having to go through the liquid state. An example of reverse sublimation is frost buildup on the ground.
Factors Affecting Gases
When the air (gas) inside the balloon is heated, it increases in volume and therefore rises.
The behavior of gases is affected by the following variables:
- Volume (V): is the space that gaseous matter occupies, which is measured in liters (L). The gas will have a greater or lesser volume depending on the separation between the particles and the space available to expand.
- Pressure (P): is the force applied per area. Pressure originates from the weight of air, therefore the higher a gas rises, the less pressure it experiences due to the less amount of air. In the case of gases, pressure is measured in atmospheres (atm).
- Temperature (T): is the measure of kinetic energy produced between the gas particles, which is measured in kelvin units (K). If a cold body of matter approaches a warm one, the cold body will raise its temperature.
These factors are in turn related to other elements inherent to gases such as:
- Quantity: it is the mass quantity of the gaseous matter and it is measured in moles (n).
- Density: refers to the relationship between volume and weight.