Question

State and explain Avogadro’s law.

Answer 1

Hint- Here, we will proceed by stating Avogadro’s law and then we will give its mathematical representation. Then, we will define ideal gas and will also mention Ideal gas law.

Complete answer:
Avogadro 's law is a gas law which states that the total number of atoms or molecules of a gas (representing the amount of gaseous substance) is directly proportional to the volume that the gas occupies at constant temperature and pressure.
According to the Avogadro’s law,
V$\propto $n where V denotes volume of the gas and n denotes number of moles of the gas
$ \Rightarrow $ V = kn where k is a constant known as Avogadro’s constant
If we have two gases having volumes as ${{\text{V}}_1}$ and ${{\text{V}}_2}$ respectively and the number of moles as ${{\text{n}}_1}$ and ${{\text{n}}_2}$ respectively.
Using the relation V =kn, we can write
$\dfrac{{{{\text{V}}_1}}}{{{{\text{V}}_2}}} = \dfrac{{{{\text{n}}_1}}}{{{{\text{n}}_2}}}$
An ideal gas is defined as one where all collisions between atoms or molecules are perfectly elastic, and where there are no attractive intermolecular forces. One can imagine it as a series of colliding perfectly hard spheres but otherwise not interacting with each other. In the case of an ideal gas, all of the internal energy is in the form of kinetic energy and any increase in internal energy is followed by temperature changes.
Three state variables may characterize an ideal gas, which are absolute pressure (P), volume ( V), and absolute temperature ( T).
The relationship between absolute pressure ( P), volume ( V) and absolute temperature ( T) can be deduced from the theory of kinetics, which is called the ideal gas law.
PV = nRT where n represents the gas moles, and R denotes the gas constant.
The law of Avogadro is also known as the theory of Avogadro, or hypothesis of Avogadro for gases. The law of Avogadro is closely related to the ideal equation of gas as it relates temperature, density, volume and quantity of substance for a given gas.
Two dissimilar ideal gasses, which occupy the same volume at a given (constant) temperature and pressure, must contain an equal number of molecules according to Avogadro 's law.

Note- While it is fully applicable to ideal gases, the law of Avogadro provides only approximate relationships for real gases. The deviation from ideal behavior of the real gases increases at low temperature and high pressure. It should be remembered that gases with comparatively small molecular masses (such as helium and hydrogen) follow the law of Avogadro to a greater degree than heavier molecules.