the kinetic gas equation given on the basis of kinetic theory of gases is;
PV=(mnu^2)/3
where P=pressure exerted by gas
V=volume of gas
m=mass of each molecule of gas
u=root mean square.
Here can anyone just tell me that m i.e mass of each molecule of gas is in amu or in grams

Given the formula:

P = \frac {nm\bar v^2}{3}

If you work the units you will see that m must be units of mass - in grams, or Kg, or whatever to make the result turn out in the units of pressue you desire. For example if n is in particles per cubic meter, m in Kg, and \bar v in meters/second, the pressure P will be in units of N/m^2, or pascals.