How to find molecular mass?

How to find relative molecular mass of a gas?

• Find the relative molecular mass using volume and weight at Room Temperature and Pressure

• Answer:

  hi!! well u could use the formula PV=nRT where p = pressure = 1atm (standard) v = volume of the gas n=no of moles = mass(m)/relative molecular mass(Mr) R=constant = 0.0821 atm l k-1 mol-1 T = temperature = 273 K (standard) therefore you have v, m, T, P, R and you want to find Mr i.e. PV = nRT but n= m/Mr therefore PV=(m/Mr)RT make Mr the subject Mr=(mRT) / (PV) there you go......... :) hope you got your answer.... ^_^