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An Explanation on the Mathematical Expression of Charles’s Law

Introduction

The law of volumes (also known as Charles’ law) is really an experimental gas law that explains how gases expand when heated. The following is a current version of Charles’ law.

When the pressure on a dry gas sample is maintained constant, the Kelvin temperature and pressure are proportional.

Volume and Temperature: Charles’s Law

Charles’s law, named after the French physicist and balloon flying pioneer Jacques Alexandre César Charles, describes the relationship between the quantity and temperature of a fixed amount of gas under constant pressure.

The equation can be given as:

Where

  • V is volume 

  • is temperature

The derivation can be shown as follows:

We know that;

V ɑ T

Therefore;

Consider, V1 and  T1be initial volume and temperature, respectively

Hence, V1T1=k                     (1)

Consider, V2 and T2 be final volume and temperature, respectively

Hence,                       (2)

Therefore, from (1) and (2)

V1/T1=V2/T2

The graph can be given as:

When a fixed quantity of gas is heated, or when the temperature is raised, the volume rises as well. Similarly, when the gas cools, its volume drops.

It’s worth noting that the unit Kelvin, rather than Celsius, is used to solve problems using Charles’ Law. The Absolute Temperature Scale is another name for the Absolute Temperature Scale.

You add to the temperature in the degrees Fahrenheit scale to convert temperature to Kelvin scale.

What is Boyle’s law?

Boyle’s law states that the pressure of an ideal gas is inverse proportion towards its absolute pressure at a constant temperature.

PV=k

where 

  • P is pressure, 

  • V is volume, and 

  • k is a constant.

When the temperature is kept constant, the rule may also be used to determine the pressure or volume of a system.

  • P1/V1=P2/V2

where:

  • P1 = initial pressure
    V1= initial volume

  • P2 = final pressure
    V2= final volume

The graph can be shown as:

Combined Gas Laws

The ratio of the combination of pressure and volume to the absolute temperature of a gas is directly proportional to its absolute, according to this formula.

The ideal gas law will be obtained by adding Avogadro’s law to the combined gas law.

Combination of Boyle’s law and Charle’s law

Boyle’s Law and Charles’ Law are integrated in the standard combined gas law.

The combined gas law contains the relationships between pressures, volume, and absolute temperature. Mathematically, it’s written as:

PVT=k

The constant, K, will change depending on the number of moles in the system. k will be a real constant value as long as the majority of moles remains constant.

So the working form of  combined gas law is:

For pressure and volume, any units will suffice, but the temperature would have to be absolute (Kelvin)..

What is Gay Lussac’s Law?

The pressure of a sample holder in a rigid cylinder rises as the temperature of the gas sample rises. The molecules of gas impact the container’s boundaries with increasing force as their kinetic energy rises, resulting in higher pressure.

Gay-Lussac’s Law: 

Gay-Lussac’s Law also states that PT=k, where is the proportionality constant.

Where,

  • is pressure

  • is temperature

  • is constant

What is Avogadro’s Law?

Avogadro’s law states that the equal volumes of various gases contain an equal number of molecules under the same circumstances of temperature and pressure.

Avogadro’s Law Formula

At constant pressure and temperature, it can be expressed as:

                                                                     

Here,

  • V is the volume of gas 

  • n is the amount of gaseous substance in moles 

  • is a constant

What is an Ideal Gas?

Avogadro’s law states that equal volumes of various gases contain the same number of molecules when heated and compressed to the same temperature and pressure.

The phrase “ideal gas” describes a hypothetical gas made up of molecules that adhere to a set of rules:

1. Ideal gas molecules are neither attracted nor repelled to one another. The sole interaction between perfect gas molecules would have been an elastic collision when they collided with each other or with the container’s walls.

2. Ideal gas molecules have no volume of their own. Because the molecules extend throughout a broad span of space, the gas takes up the volume, yet the Ideal gas molecules are represented as point particles with no volume in and of themselves.

Equation of Ideal Gas Law

The macroscopic and microscopic factors such as pressure, volume, and temperature determine the condition of an ideal gas.

The ideal gas equation can be given in the form:

Where;

  • P is the pressure of the ideal gas.

  • V is the volume of the ideal gas.

  • n is the amount of ideal gas measured in terms of moles.

  • R is gas constant.

  • T is temperature.

Conclusion

  • The physical concept known as Charles’s law states that if the pressure remains constant, the volume occupied by a certain amount of gas is precisely proportional to its absolute temperature.

  • Whenever the temperature of a gas sample in a rigid container is raised, the gas’s pressure rises as well. The increase in kinetic energy causes the molecules of gas to strike the container’s walls with more force, resulting in increased pressure.

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Frequently asked questions

Get answers to the most common queries related to the NDA Examination Preparation.

What is meant by Ideal Gas?

Ans: An ideal gas is one in which all atom-to-atom or molecule-to-molecule collisions are entirely elastic a...Read full

What is meant by Gay Lussac’s Law?

Ans: The pressure is exerted by a gas change directly with both the exact temperature of the gas, a...Read full

What is the nature of V vs T graph in Charles Law when the pressure is kept constant ?

Ans: Straight line