# Avogadro’s Law – Understand the Law with Graphical Representation

To ace in Engineering entrance exams like JEE Main, VITEEE, BITSAT, etc. you need to have a clear understanding of all the concepts from each section. Therefore, our experts have prepared this article on Avogadro’s Law – an important topic from the chemistry section. You can find a Graphical Representation of Avogadro’s Law and a simple explanation of the entire concept. Carefully go through this article and make short notes related to Avogadro’s Law for quick revision.

Read more about Hess Law, here.

**Avogadro’s Law**

Avogadro’s law states that there is indeed a direct correlation between the number of moles and the volume of gas throughout constant temperature and pressure levels. This law would apply to ideal gases, although there was a minor divergence with real gases.

If we take a real-life example of a tire, It isn’t very convenient to have a flat tire.. It does not really cushion the wheel’s rim, creating a very uncomfortable experience. The stress rises as more gas molecules are pushed into the rigid rubber as air is applied to the tire. how much air must be pumped into a tyre relies on the tire’s pressure level. Insufficient pressure and thus the tire won’t hold its shape and excess pressure may burst tire.

Learn more about the Rutherford Model of Atom, here.

## What is Avogadro’s Law?

Hypothesis of Avogadro states that equivalent volumes of gas contain the same amount of molecules at the same pressure and temperature. As a consequence, the volume of a gas is directly related to the number of moles of gas.

“Avogadro’s Law states that when temperature and pressure are kept constant the volume of a gas is directly proportional to the number of moles of the gas”

The law of Avogadro is named after the Italian scientist Amedeo Carlo Avogadro and seems to be closely connected to the ideal gas formula because it incorporates temperature, pressure-volume and volume for a given gas.

Avogadro’s law can be represented at constant pressure and temperature using the following formula:

V ∝ n

V/n = k

V = volume of the gas

n = amount of gaseous substance (often expressed in moles)

k = constant

It is in evidence every time you blow a balloon, the balloon volume rises as you introduce moles of gas by blowing it up.

**Graphical Representation of Avogadro’s Law**

Learn more about Ideal Gas Equation, here.

Therefore, the straight line travels through the origin (that means that perhaps the two volumes are directly proportional), meaning that zero moles of gas must consume zero space.

The law of Avogadro can be derived from the ideal gas equation as follows:

### PV = nRT

Where,

- ‘P’ = pressure exerted by the gas on the walls of its container
- ‘V’ = volume occupied by the gas
- ‘n’ = amount of gaseous substance (number of moles of gas)
- ‘R’ = universal gas constant
- ‘T’ = absolute temperature of the gas

Rearranging,

V/n = (RT)/P

the value of (RT)/P is a constant

Thus, V/n = k

For real gases, the rule of Avogadro offers only approximate relations. The divergence of real gasses from optimal behavior decreases at low temperatures and high pressures.

Check out the other topics of Chemistry, here.

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