1) Choose Benzene and Toluene mole fractions that do not add up to 1
   Check how DWSIM normalises when you press apply

2) Go to the page where you defined mole fractions
   Check what the normalise button does when the total is not 1

3) Go to the page where we defined the molar flow rate
   DWSIM automatically displayed the equivalent mass flow rate
   Check if these values are consistent

4)Create a stream consisting of Benzene, Toluene and Xylene 
  Carry out the previous assignments for this stream also