A discharge tube containing nitrogen gas at 25^(@)C in evacuated till the pressure is 2xx10^(-2) mm. If the volume of discharge tube is 2 litre. Calculate the number of nitrogen molecules still present in the tube (R=0*0821 L "atm mol"^(-1)K^(-1))

A discharge tube containing nitrogen gas at 25^(@)C in evacuated till

1.	A discharge tube containing nitrogen gas at 25^(@)C in evacuated till the pressure is 2xx10^(-2) mm. If the volume of discharge tube is 2 litre. Calculate the number of nitrogen molecules still present in the tube (R=0*0821 L "atm mol"^(-1)K^(-1))
Answer» Solution :STEP : 1 CALCULATION of number of moles of nitrogen. Here `P=2xx10^(-2) mm =2xx10^(-2) xx(1)/(760) atm` `V=2L, T=25^(@)C=29815K` According to ideal gas equation. `PV=nRT:. N(PV)/(RT)=2xx10^(-2)(1)/(760)xx(2)/(0821)xx(1)/(29815)` `:.n=215xx10^(-6)` Step: 2 Calculation of number of molecules. 1 MOL of nitrogen contains `=602xx10^(23)` molecules. `215xx10^(-6)` mol of nitrogen CONTAIN `=602xx10^(23)xx215xx10^(-6)` `1*29xx10^(18)` molecules