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| The Charles’s Law |
Introduction: In since 1787 Jacques Charles’s proposed a law between the relationship of volume and temperature. And it is the experimental Gas Law, which shows that how the gases tends to expand when they (gases) are heated.
Statement no.1: This Law states that “At
constant Pressure the volume of the given mass of a gas is directly
proportional to the absolute temperature”.
Statement
no.2: The
second statement of this Law states that “The
ratio of volume to temperature at constant pressure remains same”.
Mathematically
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Where V is volume, T is temperature and K is
proportionality constant of Charle’s law, V1T1 represent
the initial volume and temperature of a gas respectively and V2T2
represent the final volume and temperature of a gas respectively.
Experimental Verification of Charles’s Law
Let us consider a certain amount of gas enclosed
in a having a moveable piston. The volume is 400 ml at 100K. If the temperature
is double that is 200K then its volume will be double to 800 ml. It proves that
always remain the same.
Graphical representation of Charles’s Law
If we plot a graph paper between the volume
of the gas and the temperature at a constant pressure then the straight line
will be obtained. The length of the line will be touches – 273°C. At this temperature the volume of gases
become zero which is impossible and this temperature can’t be achieved. That’s
why the scientist started a new scale from here which is known as a Kelvin scale or absolute temperature scale or Absolute Zero.
Kelvin scale or Absolute temperature scale
This absolute scale or Kelvin scale was
introduced by Lord Kelvin to make the
mathematical calculation easy because this scale does not have any negative
sign and zero value. In this scale
degree sign is also not used. This scale starts from OK which is equal to – 273°C which is known as absolute zero therefore sometimes it is called Absolute Zero scale.While working in
this different formula is used to change temperature centigrade into kelvin and
kelvin into centigrade is as follow
Change Temperature into Kelvin
T in K =°C + 273
T in °C= K – 273
