Measurable Properties of Gases: Charles’s Law

Towards the end of the eighteenth century, various scientists created gas laws. 

The main among these are: 

• Boyle’s law: This describes the link between a gas’s pressure and volume.
• Charles’s law: The connection between the volume filled by gas and its absolute temperature is given by Charles’ law.
• Gay-Lussac’s law: This law describes the connection between the pressure exerted by a gas on the walls of its container and the absolute temperature associated with the gas.
• Avogadro’s law: This law describes the link between the volume occupied by a gas and the amount of gaseous material.

The combined gas law is developed by combining these four laws. It is also known as the ideal gas law.

Although the combination of these rules explains the behaviour of an ideal gas, they are quite similar to the behaviour of actual gases. Under typical conditions, all gases act similarly. Variations in behaviour are seen when the physical conditions like temperature, pressure and gas volume vary. Changes in these characteristics cause gas behaviour to alter. As a result, the gas laws characterise these variations in gas behaviour. 

In this article, we take a closer look at Charles’s law and its applications.

Charles’s Law

According to Charles’s law, in a closed system, the volume of a gas is directly proportional to its temperature (in Kelvin). As a result, this law describes the link between the gas’s temperature and volume. We can use the following formula to express Charles’s law.

V ∝ T 

Where

 V = volume of gas, and

T = temperature of the gas in Kelvin.

This can also be given as:

V1 / T1 = V2 / T2

Furthermore,

 V1 / T1 = V2 / T2 ⇒ V/T = constant= K2

So, 

V= K2T.

As a result, the value of K2 is determined by the gas’s pressure, volume, and unit of volume.

The discovery and naming of the law

The law was named after the French mathematician, physicist, inventor, and balloonist Jacques Alexandre César Charles. He made history by being the first person to launch a crewed hydrogen-filled gas balloon. 

Natural philosopher Joseph Louis Gay-Lussac wrote a paper outlining how gases expand when heated just a few days after the first human-crewed hot air balloon flight in 1802. He attributed it to Jacques Charles’s unpublished work from the 1780s. In honour of Charles, Gay-Lussac titled the statute ‘Charles’s law’.

In 1787, Charles experimented with filling five identical containers with various gases. After that, he raised the temperature of the containers to 80 degrees Celsius. He then saw that all gases had grown in volume by the same amount. Gay-Lussac mentioned this experiment in his paper from 1802. Charles deduced that the volume of gas grows linearly with the absolute temperature of that gas under constant pressure.

Application of Charles’s Law in real life

This law has several applications in everyday life. 

• A balloon loses its shape when it is taken from a warm environment to a cold environment, and it regains its shape when it is returned to the warm environment from the cold environment. This occurs because the volume reduces when the temperature drops. Now, according to Charles’s law, the temperature rises as soon as you enter a heated room. As the temperature rises, the volume rises as well. As a result, the balloon returns to its former shape.

• Baking yeast is commonly used to generate fluffy baked items. The release of carbon dioxide bubbles is caused by yeast. When the temperature rises, the carbon dioxide bubbles expand, acting as a leavening agent, causing the bread items to puff up. With a higher temperature, the carbon dioxide bubbles will expand even more.

• A hot air balloon works in accordance with Charles’s law. Temperature and volume are precisely proportional to each other, according to Charles’s Law. When you heat a gas, it expands. As the gas expands, the density of the gas decreases, and the balloon rises into the air. Warm air is less dense than cold air, which is lighter. Warm air also has less mass per unit volume.

• The tyres of cars shrink in chilly weather.
• When you take a basketball outside on the ground in the winter, the ball shrinks as the temperature drops.
• Charles’s law governs the operation of pop-up turkey thermometers—the gas inside the thermometer expands as the turkey cooks. 
•  An overfilled tube placed in a pool might cause bloat and rupture.

Conclusion

The formula for Charles’s Law can be understood through Boyle’s law and the combined gas law. 

The mathematical version of Charles’s law, V1T1=V2T2, 

and the combined gas law: p1V1T1=p2V2T2, may be derived.