2. A stream containing ethane, propane, and butane has a mass flow rate of 100.0 g/s.

a. Write an expression for the mass fraction of propane, X_p, in terms of the mass fractions of ethane and butane, X_e and X_b. b.

b. Write an expression for the molar flow rate of ethane, N(lb-mole C H /h), in terms of the mass fraction of this species, X.