Gases are molecular compounds that have characteristics such as great compressibility and the ability to expand, these compounds do not have a fixed volume, they are miscible with each other and in any proportion.
Gases are substances whose molecules completely lose their attraction to each other and disperse a lot from each other, in addition, these molecules are always in disordered movement. This movement causes some particles to collide when they are confined in a container, and this collision generates what we call the pressure that the gas exerts on certain surfaces.
Pressure is force per unit area. Heating causes molecules to move faster, which increases their average kinetic energy (E cin). This energy present in the molecules of a gas is directly proportional to the absolute temperature, as in the formula:
And cin = KT
The gas that obeys this principle is called an ideal gas (perfect gas), but as this does not occur most of the time, real gases arise. What makes real gases not perfect is the interaction between their molecules.
A gas, whatever it may be, can undergo three types of variation: volume, temperature and pressure. These are the state variables, let’s see the definition for each one:
Pressure: the pressure of a gas can be defined as the force it exerts in a perpendicular direction over the area of a given surface.
Volume: it is impossible to determine the exact volume of a gas, as they always occupy the total volume of the container in which they are confined;
Temperature: relates to the degree of agitation of the particles, the greater the agitation, the higher the temperature of the system.
Don’t stop now… There’s more after the publicity 😉
By Líria Alves
Graduated in Chemistry