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Charles's law , Jolly's law and General gas law

From Online Sciences - November 12, 2017

The gases contract by cooling and expand by heating , Equal volumes of different gases expand equally when heated through the same temperature rise , In other words they have the same volume expansion coefficient , Charless law expresses the effect of temperature on the volume of a gas at constant pressure .

Charless law

All gases have the same volume expansion coefficient , at constant pressure , so , the volume expansion coefficient ( v ) can be determined from the following relation :

v=( Vol ) / [( Vol )0C t ]

v= [( Vol )t( Vol )0C ] / [( Vol )0C t ]

The measuring unit of the volume expansion coefficient is ( Kelvin )1 = ( K1 ) .

The volume expansion coefficient of gas at constant pressure ( v ) is the increase in volume at constant pressure per unit volume at 0C for rise in temperature , or it is the ratio between the increase in volume to the original volume at 0 C for 1 C rise in temperature at constant pressure .

When the volume expansion coefficient of a gas under a constant pressure = ( 1/273 ) K1 , It means that the increase in volume at constant pressure per unit volume at 0 C for 1 C rise in temperature = 1/273 of the original volume .

To convert from Celsius to Kelvin , we use the following relation : T (K ) = t C + 273

Where : ( T )Temperature on Kelvin scale , ( t )Temperature on Celsius scale .

Charless law : At constant pressure , the volume of a given mass of gas expands by 1/273 of its original volume at 0C per each degree Kelvin rise in temperature , or at constant pressure , the volume of fixed mass of gas is directly proportional to its temperature on Kelvin scale .

Charless law mathematical formula : V1 / V2 = T1 / T2

( Vol )1 / ( Vol )2 = T1 / T2

T1 = 273 + t1 , T2 = 273 + t2

( Vol )1 / ( Vol )2 = 273 + t1 / 273 + t2

( Vol )1 / ( Vol )2 = ( 1 + 1/273 t1 ) / ( 1 +1/273 t2 ) , v= 1/273

( Vol )1 / ( Vol )2 = ( 1 + v t1 ) / ( 1 + v t2 )

If two gases are mixed at constant pressure , then

( Vol ) / T ( mix. ) = [ ( Vol )1 / T1 ] + [ ( Vol )2 / T2 ]

Jollys law or pressure law

Jollys law expresses the relation between gas pressure and its temperature at constant volume , The pressure of gases increases by increasing the temperature , The increase in the pressure is constant for all gases .

At constant volume , the pressure of a given mass of a gas increases by increasing temperature , At constant volume equal pressures of different gases increase equally when heated to the same temperature .

Pressure expansion coefficient is constant for all gases , Equal pressures of different gases increase equally when heated through the same rise in temperature because expansion coefficient for any gas at constant volume is constant .

At constant volume , the increase in the pressure (P ) is directly proportional to :

PP0 Ct

P = constant P0 Ct

P = p P0 Ct

Where ( p ) is the pressure expansion coefficient

p= ( PtP0 C ) / ( P0 Ct )

P1 / P2 = ( 1+ pt1 ) / ( 1+ pt2 )

General gas law

P1 / 1 T1 = P2 / 2 T2

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