The Ideal Gas Law; equation and facts
Everything that exists around us has its own chemical identity. The smallest particle in the universe is called an atom. Anything that
- Occupies space
- Has mass
- Can be seen and touched (like soil and water), or can't see (like air) is a matter.
These matters can be classified broadly into three stages
- Solid
- Liquid
- Gas
Obviously, you may have seen the solid matter within which particles are close together and held tightly. The solid matter has a structure with a definite shape, with a smaller degree of motion. Though the particles in a liquid are close together, they are not held tightly. They are freely moving compared with the solid particles. But in the gas state, particles are with large distances where they are allowed to move freely.
In this section, let's focus our attention on the behavioral nature of particles in a gaseous state, under normal conditions of temperature and pressure. Our discussion consists
- Physical properties of the gaseous state
- Different gas laws
- What is an ideal gas
- Ideal gas law and the equation
- Calculations based on ideal gas equation
- Example of calculations based on ideal gas equation
What are the physical properties of the gaseous state
- Gases are highly compressible
- These exert pressure in all directions equally
- Than solids and liquids, gases have a much lower density
- Since gases don’t have fixed volume and shape, these assume the volume and the shape of the container
- Gases able to mix completely and evenly in all proportions without any mechanical aid
Different laws related to the gaseous state
Since the forces between gas particles are negligible, the behavior can be explained by the same general laws. From the initial development of scientific studies, several scientists have been involved with experiments that resulted in amazing findings.
There are different laws developed through experimental results. Generally, these laws include relationships of measurable properties of gases.
The properties like
- Pressure
- Temperature
- Amount (moles or mass), has been considered.
Since the relationships of such variables describe the state of the gas, getting these into consideration is really important. Further, the formulation of the gas laws has utilized the interdependence of these variables.
Examples of the gas laws
- Ideal gas law
- Boyle law (pressure-volume relationship)
- Charles law (temperature-volume relationship)
- Avogadro law (amount-volume relationship)
- Combined gas law
- Dalton's law of particle pressure
What is an ideal gas?
When we assume that intermolecular forces don’t exist among the molecules of a gas, we can call such a gas an ideal gas. Therefore no attraction or repulsion is exhibited among the gas molecules. Moreover, when compared with the volume of the container, the gas particles are considered to have a negligible volume.
What is the Ideal Gas Law
Since the behavior of gas is affected by factors including
- Absolute temperature (T)
- Pressure (P)
- Volume (V)
- Amount (n, moles) of the gas, the relation of these factors can be expressed as follows
This expression is known as the ideal gas equation or ideal gas law. R is the gas constant, which is the same for each gas.
So we would conclude that any gas which this relationship, under any given temperature and volume can be referred to as an ideal gas.
Then let's try some different forms that we can express the ideal gas equation, in order to estimate the mass and density of a particular gas.
We would some simple modifications to the ideal gas equation as follows.
PV = nRT
Then we can write P = (n/v) RT
(n/v) = Concentration (C)
Then P = cRT
And also we know that n (number of moles) = m/M, where m is the mass and M is the molecular mass of the given gas. So we can express that,
PV = (m/M)RT
Density can be expressed as m/V. Therefore,
P = (m/V) (1/M) RT
P = (dRT) / M
Further Ideal gas law has provided the basis for deriving different other gas laws, under specific conditions which we would consider within the next content.