**Charles’ law of gases**

**Charles’ law of gases**

** Answer:** In 1787 a French scientist, mathematician, inventor and balloonist J.Charles (Jacques Alexander Cesar Charles) studies the relationship among volume and temperature at costant pressure. He described how gases tend to expand when heated.

** Statement or Definition: **According to this law “ the volume of a given mass of a gas is directly proportional to the absolute temperature if the pressure is kept constant.

OR

When pressure is kept constant the volume of a given mass of a gas is directly proportional to absolute temperature on kelvin scale.

**Mathematical Expression: **

AS VOLUME α TEMPERATURE

OR V α T

OR V = KT

OR V/T = K

Where k is proportionality constant. If temperature of the gas is increased, its

volume also increases. When temperature is changed from T1 to T2 , the volume changes from V1 to V2 . The mathematical form of Charles’ Law in this case will be:

V1/T1 = K AND V2/T2 = K

As both equations have same value of constant, therefore , their variables are also equal to each other.

V1/T1 =V2/T2

**Experimental Verification of Charles’s Law**

Let us take a certain amount of gas enclosed in a cylinder having a movable piston. If the initial volume of the gas V1 is 50 cm3 and initial temperature T1is 25 °C, on heating the cylinder up to 100 °C, its new volume V2 is about 62.5 cm3. The increase in temperature, increases the volume.