One mole of an ideal gas has a capacity to hold 23 litres of liquid at standard temperature i. e. 273 Kelvin and has a pressure of 1 atmosphere. One atmospheric pressure is equal to 101325 Pascal or 1.01325 bar. This type of pressure can be seen at sea level, as we go up the pressure is decreases because heavy gases remain lower so that's why there is less pressure on hilly areas.
