Q. 255.0( 2 Votes )
Value of universal gas constant (R) is same for all gases. What is its physical significance?
The universal gas constant;
Its unit is obtained from expression, R=
Pressure = = =
Volume = length3
Thus, unit of R is energy per mole per Kelvin. R is the amount of
Work (energy) obtained from per mole of gas when its temperature raised by 1 kelvin.
Unit R depends on units of P, V and T. If pressure is measured in Pascal, per
Mole volume is measured in m3 and temperature is measured in Kelvin then
Unit of ‘R’ are in Pa m3K-1mol-1 or JK-1mol-1. Joule is the unit of work done so
‘R’ is work done per Kelvin per mole. For 1 mole gas
The dimensions of the universal gas constant R are energy per degree per mole. In the metre-kilogram-second system, the value of R is 8.3144598 joules per Kelvin per mole.
Hence R only depends on unit of different parameter P, V, n, T. So R values same for all gases.
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